U.S. patent application number 12/550148 was filed with the patent office on 2009-12-24 for navigation apparatus.
This patent application is currently assigned to MITSUBISHI ELECTRIC CORPORATION. Invention is credited to Yukio Goto, Tomoya Ikeuchi, Masayuki Ishida, Tadatomi ISHIGAMI, Atsushi Kohno, Hiroyuki Kumazawa, Norihiro Nishiuma, Yoshitsugu Sawa, Mitsuo Shimotani, Masaharu Umezu.
Application Number | 20090319174 12/550148 |
Document ID | / |
Family ID | 38375129 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090319174 |
Kind Code |
A1 |
ISHIGAMI; Tadatomi ; et
al. |
December 24, 2009 |
NAVIGATION APPARATUS
Abstract
A navigation apparatus includes an unregistered road detecting
means for setting up a detection start point and a detection end
point for an unregistered road on registered roads which are
respectively located before and behind sections in which matching
result data indicates a free state, respectively, the matching
result data indicating a matching state when the vehicle is
traveling each of the registered roads, for performing a coordinate
transformation on a traveling path which is created from
positioning data and which is extending between the two points so
that the traveling path has coordinates which match with the
coordinates of a registered road between them, and for detecting
the coordinates of the unregistered road from a portion of the
coordinate-transformed traveling path which does not overlap any
registered road, and a road data generating means for creating road
data about the unregistered road from the coordinates of the
unregistered road.
Inventors: |
ISHIGAMI; Tadatomi; (Tokyo,
JP) ; Nishiuma; Norihiro; (Tokyo, JP) ; Sawa;
Yoshitsugu; (Tokyo, JP) ; Goto; Yukio; (Tokyo,
JP) ; Kumazawa; Hiroyuki; (Tokyo, JP) ; Umezu;
Masaharu; (Tokyo, JP) ; Ikeuchi; Tomoya;
(Tokyo, JP) ; Kohno; Atsushi; (Tokyo, JP) ;
Ishida; Masayuki; (Tokyo, JP) ; Shimotani;
Mitsuo; (Tokyo, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
MITSUBISHI ELECTRIC
CORPORATION
Tokyo
JP
|
Family ID: |
38375129 |
Appl. No.: |
12/550148 |
Filed: |
August 28, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11680971 |
Mar 1, 2007 |
|
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|
12550148 |
|
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Current U.S.
Class: |
701/533 |
Current CPC
Class: |
G01C 21/26 20130101;
G01C 21/30 20130101; G09B 29/102 20130101 |
Class at
Publication: |
701/201 |
International
Class: |
G01C 21/36 20060101
G01C021/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2006 |
JP |
2006-066349 |
Nov 17, 2006 |
JP |
2006-311883 |
Claims
1. A navigation apparatus comprising: a sensor for detecting a
behavior of a vehicle; a positioning means for estimating the
behavior of the vehicle on a basis of a signal from said sensor; a
road-map-data storage means for storing road data; a road matching
means for comparing positioning data sent thereto, as an estimation
result, from said positioning means with the road data read from
said road-map-data storage means so as to identify a current
position of the vehicle, and for judging whether the identification
is placed in either a matching state in which there are one or more
candidates for an existing position of the vehicle on a registered
road shown by said road data or a free state in which the current
position of the vehicle is finally identified as being out of any
registered road, and then outputting matching result data
indicating the state of the identification, and for outputting
position candidate data indicating candidates for the existing
position of the vehicle on registered roads when the state of the
identification is the matching state; an unregistered road
detecting means for selecting, as a detection start point on a
registered road and a detection end point on a registered road for
an unregistered road, two candidates from the candidates for the
existing position of the vehicle on registered roads, which are
shown by the position candidate data from said road matching means,
and for outputting travel path data about a travel path from said
detection start point to said detection end point, which is created
on a basis of the positioning data from said positioning means; and
a road data generating means for creating road data about the
unregistered road on a basis of coordinates of the unregistered
road created by said unregistered road detecting means, and for
storing the created road data in said road-map-data storage
means.
2. The navigation apparatus according to claim 1, wherein when the
state of the identification is the matching state, said road
matching means outputs connection relation data indicating a
connection relation between candidates for the existing position of
the vehicle shown by position candidate data obtained at a previous
time and candidates for the existing position of the vehicle shown
by position candidate data obtained at a current time, in addition
to the matching result data and the position candidate data, and
said unregistered road detecting means sets up the detection start
point and the detection end point for the unregistered road on a
registered road in which a connection continues to exist while the
vehicle travels a predetermined distance or longer from the
position candidate data and the connection relation data from said
road matching means.
3. The navigation apparatus according to claim 1, wherein said
apparatus further includes an input means for inputting
coordinates, and an unregistered road editing means for creating
coordinates of the unregistered road which connect the coordinates
inputted by said input means using a traveling path shown by the
travel path data from said unregistered road detecting means, and
the coordinates inputted by said input means, and wherein said road
data generating means creates road data about the unregistered road
on a basis of the coordinates of the unregistered road created by
said unregistered road editing means, and stores the created road
data in said road-map-data storage means.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/680,971, filed on Mar. 1, 2007, and is based upon and claims
the benefit of priority from prior Japanese Patent Application Nos.
2006-066349, filed Mar. 10, 2006, and 2006-311883, filed Nov. 17,
2006.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a navigation apparatus.
More particularly, it relates to a technology for, when a vehicle
equipped with the navigation apparatus has traveled an unregistered
road about which road data is not registered in the navigation
apparatus, creating road data about the unregistered road from the
traveling path of the vehicle.
BACKGROUND OF THE INVENTION
[0004] 2. Description of Related Art
[0005] Conventionally, a navigation apparatus which creates road
data about an unregistered road and registers the road data in road
map data when a vehicle equipped with the navigation apparatus has
traveled the unregistered road about which road data is not
registered in the road map data is known. For example, patent
reference 1 discloses a navigation apparatus which stores the
traveling path of a vehicle when the vehicle has traveled an
off-road, and, after that, reads the traveling path so as to
display it, and a navigation method at a time when the vehicle is
traveling an off-road. This navigation apparatus disclosed by
patent reference 1 creates road data automatically on the basis of
the traveling path of the vehicle in a section in which the current
position of the vehicle cannot be map-matched onto any road
indicated by road data. If the navigation apparatus can determine
that the current position of the vehicle is out of any road
indicated by road data when the vehicle has traveled from a
registered road indicated by road data created automatically to an
unregistered road about which road data is not registered, the
navigation apparatus defines, as a branch point of the registered
road, the current position of the vehicle, and creates road data
automatically on the basis of the traveling path of the vehicle
after the branch point.
[0006] Patent reference 2 discloses a method of creating road map
data which is applied in order to create road map data for use in a
navigation system or the like. In accordance with this
road-map-data creation method, the traveling path M of a vehicle
which has traveled an unknown route extending from a first point A
(i.e., a vehicle departure point) whose position on the road map
data is known to a second point B (i.e., a vehicle return point)
whose position on the road map data is known, the first and second
points being set up manually by the user, is obtained, a rotation
operation around the first point A and a scaling operation are
performed on the traveling path M of the vehicle in order to make
the end point of the traveling path M agree with the second point B
so that the traveling path M of the vehicle is corrected for, and
road map data is created on the basis of the corrected traveling
path. According to this creation method of creating road map data,
only one drive of the vehicle along a route about which road map
data should be created makes it possible to easily create correct
road map data about a road, such as a road newly constructed,
without having to wait for supply of road map data obtained by
taking an aerial photograph or the like of the road.
[Patent reference 1] JP,2002-357431,A [Patent reference 2]
JP,06-201392,A
[0007] However, the prior art navigation apparatus disclosed by
patent reference 1 has the following problems. That is, because the
prior art navigation apparatus is so designed as to carry out a map
matching process of comparing road data with the current position
of the vehicle on the assumption that the vehicle travels a road,
it is difficult for the prior art navigation apparatus to determine
that the current position of the vehicle is out of any registered
road indicated by the road data when it is placed in a matching
state in which the current position of the vehicle is map-matched
onto a registered road, and, when the vehicle travels an
unregistered road while the prior art navigation apparatus is
placed in a free state (i.e., a state which is not the matching
state), the prior art navigation apparatus may determine that the
current position of the vehicle is on a registered road incorrectly
if the registered road runs in parallel with and in the vicinity of
the traveling path of the vehicle. On the other hand, when there
are two or more roads near the current position of the vehicle, the
prior art navigation apparatus does not determine that the current
position of the vehicle is on a registered road until it will have
continued to recognize a similarity in the shape of the traveling
path of the vehicle and consistency of the current position of the
vehicle with the registered road while the vehicle has been
traveling a predetermined distance or longer. A problem with the
prior art navigation apparatus is therefore that when it detects
the coordinates of an unregistered road and registered roads to
which the unregistered road is connected from the traveling path of
the vehicle in a section where the prior art navigation apparatus
is placed in the free state in which the current position of the
vehicle is out of any registered road, large errors occurs in the
detection results.
[0008] A problem with the prior art creation method of creating
road map data disclosed by patent reference 2 is that a navigation
system using the creation method cannot detect any unregistered
road when the user cannot operate the navigation system even if the
user wants to operate it (e.g., when the user is driving a
well-trafficked road) or when the user has forgotten to operate the
navigation system, the navigation system cannot detect any
unregistered road, and, when the user has failed to operate it
(when the user is driving an unfamiliar area, the user may not
perform operations correctly to set up the first and second
points), the navigation system specifies roads connected to an
unregistered road incorrectly.
SUMMARY OF THE INVENTION
[0009] The present invention is made in order to solve the
above-mentioned problems, and it is therefore an object of the
present invention to provide a navigation apparatus which, when a
vehicle equipped with the navigation apparatus travels a road
including an unregistered road which is not registered in road map
data, can detect the coordinates of the unregistered road from the
traveling path of the vehicle automatically and correctly so as to
create road data about the unregistered road.
[0010] In accordance with the present invention, there is provided
a navigation apparatus including: a sensor for detecting a behavior
of a vehicle; a positioning means for estimating the behavior of
the vehicle on a basis of a signal from the sensor; a road-map-data
storage means for storing road data; a road matching means for
comparing positioning data sent thereto, as an estimation result,
from the positioning means with the road data read from the
road-map-data storage means so as to identify a current position of
the vehicle, and for judging whether the identification is placed
in a matching state in which the current position is finally
identified as being on a registered road defined by the road data,
in a pending state in which whether or not the current position is
on a registered road is being judged, or in a free state in which
the current position is finally identified as being out of any
registered road, and then outputting matching result data
indicating the state of the identification; an unregistered road
detecting means for setting up a detection start point and a
detection end point for an unregistered road on registered roads
which are respectively located before and behind sections in which
the matching result data from the road matching means indicates
that the state of the identification is the free state,
respectively, the matching result data indicating that the state of
the identification is the matching state when the vehicle travels
along each of the registered roads, for performing a coordinate
transformation on a traveling path which is created on a basis of
the positioning data from the positioning means and which is
assumed to extend from the detection start point to the detection
end point in a coordinate system so that a start point of the
traveling path has coordinates which match with coordinates of the
detection start point and an end point of the traveling path has
coordinates which match with coordinates of the detection end
point, and for detecting coordinates of the unregistered road from
a portion of the coordinate-transformed traveling path which does
not overlap any registered road if each of an amount of movement in
a coordinate system, an expansion and contraction coefficient, and
a rotation angle of the traveling path, which are caused by the
coordinate transformation, falls within a predetermined range which
is estimated from the accuracy of the current position of the
vehicle and the accuracy of correction of the sensor; and a road
data generating means for creating road data about the unregistered
road on a basis of the coordinates of the unregistered road
detected by the unregistered road detecting means, and for storing
them in the road-map-data storage means.
[0011] The navigation apparatus according to the present invention
defines, as a detection section for an unregistered road, a section
between two points respectively on registered roads in which the
state of the identification of the current position of the vehicle
is the matching state, the two points being respectively located
before and behind sections in which the state of the identification
is the free state, performs a coordinate transformation on a
traveling path between the two points which is estimated regardless
of processing carried out by the road matching means so that the
start point and end point of the traveling path have coordinates
which match with the coordinates of the two points, respectively,
determines that sections of the traveling path which are similar to
parts of the registered roads, respectively, and which are running
in parallel with the parts of the registered roads overlap the
registered roads, respectively, if each of the amount of movement
in the coordinate system, expansion and contraction coefficient,
and rotation angle of the traveling path, which are caused by the
coordinate transformation, falls within a predetermined range which
is estimated from the accuracy of the current position of the
vehicle and the accuracy of correction of the sensor, and removes
the sections of the traveling path from the traveling path, and
then detects the coordinates of the unregistered road from the
remaining traveling path. Therefore, the navigation apparatus in
accordance with the present invention can prevent detection of an
unregistered road with a low degree of reliability, and can detect
the coordinates of an unregistered road with a higher degree of
accuracy. As a result, the navigation apparatus in accordance with
the present invention can carry out route searching and route
guidance on the basis of the road data including data about
unregistered roads.
[0012] Further objects and advantages of the present invention will
be apparent from the following description of the preferred
embodiments of the invention as illustrated in the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram showing the structure of a
navigation apparatus according to embodiment 1 of the present
invention;
[0014] FIG. 2 is a flow chart showing interruption processing
carried out by the navigation apparatus according to embodiment 1
of the present invention;
[0015] FIG. 3 is a flow chart showing regular processing carried
out by the navigation apparatus in accordance with embodiment 1 of
the present invention;
[0016] FIG. 4 is a flow chart showing the details of an
unregistered road detection process of the regular processing
carried out by the navigation apparatus in accordance with
embodiment 1 of the present invention;
[0017] FIG. 5 is a diagram showing a positional relationship
between a detection start point and a vehicle departure point for
an unregistered road in the navigation apparatus in accordance with
embodiment 1 of the present invention;
[0018] FIG. 6 is a diagram for explaining historical data created
in order to set up the detection start point for the unregistered
road in the navigation apparatus in accordance with embodiment 1 of
the present invention;
[0019] FIG. 7 is a diagram showing a method of setting up an
interpolation point of a traveling path in the navigation apparatus
in accordance with embodiment 1 of the present invention;
[0020] FIG. 8 is a diagram showing a positional relationship
between the detection end point for the unregistered road, and
points at which the state of the identification of the current
position of a vehicle has changed from a free state to a pending
state and then to a matching state in the navigation apparatus in
accordance with embodiment 1 of the present invention;
[0021] FIG. 9 is a diagram showing a procedure for detecting the
coordinates of the unregistered road from the traveling path
including the unregistered road in the navigation apparatus in
accordance with embodiment 1 of the present invention;
[0022] FIG. 10 is a diagram showing a procedure for connecting
portions into which the traveling path is separated due to a
position jump which occurs immediately after the vehicle has passed
through a tunnel into a single traveling path, in a navigation
apparatus in accordance with embodiment 2 of the present
invention;
[0023] FIG. 11 is a diagram showing occurrence of a phenomenon in
which the coordinates of a traveling path have variations when the
vehicle travels along an identical unregistered road a plurality of
times, in a navigation apparatus in accordance with embodiment 3 of
the present invention;
[0024] FIG. 12 is a diagram for explaining a setup of a detection
end point for an unregistered road at a time when the state of the
identification of the current position of the vehicle changes to a
matching state while the vehicle is traveling along one of
registered roads running in two different directions after the
vehicle has passed the unregistered road, in the navigation
apparatus in accordance with embodiment 3 of the present
invention;
[0025] FIG. 13 is a diagram for explaining a judgment method of
judging a vehicle departure point by taking direction errors of a
positioning means into consideration in a navigation apparatus in
accordance with embodiment 4 of the present invention;
[0026] FIG. 14 is a diagram for explaining a method of setting up a
detection end point for an unregistered road in a navigation
apparatus in accordance with embodiment 5 of the present
invention;
[0027] FIG. 15 is a diagram for explaining a state in which a road
matching means incorrectly matches the current position of the
vehicle onto a registered road which is running in parallel with
and in the vicinity of an unregistered road, and a method of
judging whether a setup of a detection end point can be carried out
using an unregistered road detecting means, in a navigation
apparatus in accordance with embodiment 6 of the present
invention;
[0028] FIG. 16 is a diagram for explaining a method of judging
whether road data can be created in a case in which the state of
identification of the current position of the vehicle changes from
a matching state to a free state at a time when the vehicle makes a
right or left turn, in a navigation apparatus in accordance with
embodiment 7 of the present invention;
[0029] FIG. 17 is a diagram for explaining a method of setting up a
detection end point for an unregistered road at a time when the
vehicle has departed from a highway to enter a local street through
an unregistered highway IC, in a navigation apparatus in accordance
with embodiment 8 of the present invention;
[0030] FIG. 18 is a diagram for explaining a method of setting up a
detection end point for an unregistered road when it is determined
that two road types of registered roads (e.g., a highway and a
local street) are running in parallel with and in the vicinity of
the traveling path of the vehicle after the vehicle has passed
through an unregistered road, in a navigation apparatus in
accordance with embodiment 9 of the present invention;
[0031] FIG. 19 a diagram showing a transition of the current
position of the vehicle identified by a road matching means at a
time when the vehicle is traveling along a road containing an
unregistered road section, to explain a method of carrying out a
setup of candidates for a vehicle departure point and candidates
for a vehicle return point, and specification of the unregistered
road section, in a navigation apparatus in accordance with
embodiment 11 of the present invention;
[0032] FIG. 20 is a flow chart showing the details of a first half
of an unregistered road detection process of regular processing
carried out by the navigation apparatus in accordance with
embodiment 11 of the present invention;
[0033] FIG. 21 is a flow chart showing the details of a second half
of the unregistered road detection process of the regular
processing carried out by the navigation apparatus in accordance
with embodiment 11 of the present invention;
[0034] FIG. 22 is a diagram for explaining positioning data which
is used in a navigation apparatus in accordance with embodiment 12
of the present invention; and
[0035] FIG. 23 is a block diagram showing the structure of a
navigation apparatus in accordance with a variant of embodiment 12
of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Hereafter, the preferred embodiments of the invention will
now be described with reference to the accompanying drawings.
Embodiment 1
[0037] FIG. 1 is a block diagram showing the structure of a
navigation apparatus according to embodiment 1 of the present
invention. This navigation apparatus is provided with a GPS (Global
Positioning System) receiver 1, an angular velocity sensor 2, a
velocity sensor 3, a signal processing unit 4, and a display unit
5. The sensors of this navigation apparatus according to the
present invention thus include the GPS receiver 1, angular velocity
sensor 2, and velocity sensor 3.
[0038] The GPS receiver 1 receives GPS electric waves transmitted
thereto from GPS satellites by way of a GPS antenna 1a, and
generates a GPS signal. The angular velocity sensor 2 detects the
angle of turning of a vehicle equipped with the navigation
apparatus, and generates an angular velocity signal. The velocity
sensor 3 detects the velocity of the vehicle and generates a
velocity signal. The GPS signal generated by the GPS receiver 1,
the angular velocity signal generated by the angular velocity
sensor 2, and the velocity signal generated by the velocity sensor
3 are sent to the signal processing unit 4 as signals indicating
the behavior of the vehicle.
[0039] The signal processing unit 4 consists of, for example, a
computer, and runs according to a control program which is stored
in a memory (not shown) in advance so as to carry out a process of
implementing functions needed for navigation, for example, position
detection, route searching, route guidance, etc. The details of
this signal processing unit 4 will be explained below.
[0040] The display unit 5 consists of, for example, a liquid
crystal display, and displays various pieces of information on the
screen thereof according to display data sent thereto from the
signal processing unit 4. For example, the display unit 5
superimposes and displays the current position of the vehicle, a
route, etc. on an on-screen map.
[0041] The above-mentioned signal processing unit 4 is provided
with a positioning means 41, a road matching means 42, a
road-map-data storage means 43, a display control means 44, an
unregistered road detecting means 45, and a road data generating
means 46.
[0042] The positioning means 41 estimates the behavior of the
vehicle, and more specifically, estimates the current position,
traveling direction, velocity, and so on of the vehicle on the
basis of the velocity signal sent from the velocity sensor 3, the
GPS signal sent from the GPS receiver 1, and the angular velocity
signal sent from the angular velocity sensor 2. The results
estimated by this positioning means 41 are then sent, as
positioning data, to the road matching means 42 and unregistered
road detecting means 45.
[0043] The road matching means 42 compares the positioning data
sent from the positioning means 41 with road data read from the
road-map-data storage means 43 so as to identify the current
position of the vehicle, and further judges whether the state of
the identification of the current position of the vehicle is a
matching state in which the current position of the vehicle is
finally determined to be on a road defined by the road data
(referred to as a "registered road" from here on), a pending state
in which whether or not the current position of the vehicle is on a
registered road is being determined, or a free state in which the
current position of the vehicle is finally determined to be out of
any registered road. The judgment result obtained by this road
matching means 42 is sent, as matching result data, to the display
control means 44 and unregistered road detecting means 45.
[0044] The road-map-data storage means 43 stores the road data. The
road data stored in this road-map-data storage means 43 can be read
by the road matching means 42, display control means 44,
unregistered road detecting means 45, and road data generating
means 46. Furthermore, road data generated by the road data
generating means 46 can be stored in this road-map-data storage
means 43.
[0045] The display control means 44 generates display data for
superimposing and displaying the current position of the vehicle,
the route, etc. on an on-screen map on the basis of the matching
result data sent from the road matching means 42, the road map data
read from the road-map-data storage means 43, and the road data
sent from the road data generating means 46. The display data
generated by this display control means 44 are sent to the display
unit 5.
[0046] The unregistered road detecting means 45 automatically
detects the coordinates of an unregistered road and the coordinates
of each registered road to which this unregistered road is
connected (simply referred to as "the coordinates of an
unregistered road" in the specification and claims of the present
invention) from the traveling path of the vehicle at a time when
the vehicle has traveled along the unregistered road about which
road data has not been registered in the road-map-data storage
means 43 on the basis of the positioning data sent from the
positioning means 41, the matching result data sent from the road
matching means 42, and the road data read from the road-map-data
storage means 43. The coordinates of the unregistered road thus
detected by the unregistered road detecting means 45 are sent to
the road data generating means 46.
[0047] On the basis of the coordinates of the unregistered road
sent from the unregistered road detecting means 45, and the road
data read from the road-map-data storage means 43, the road data
generating means 46 generates road data about the unregistered
road. The road data generated by the road data generating means 46
are sent to the road-map-data storage means 43 and stored in this
road-map-data storage means 43 while they are also sent to the
display control means 44.
[0048] Next, the operation of the navigation apparatus according to
embodiment 1 of the present invention which is constructed as
mentioned above will be explained schematically. FIG. 2 is a flow
chart showing an interruption process carried out by the
positioning means 41 of the navigation apparatus according to
embodiment 1 of the present invention.
[0049] The interruption process is started in response to an event.
To be more specific, when the GPS signal has been sent thereto from
the GPS receiver 1, the positioning means starts the interruption
process. In this interruption process, the positioning means 41
carries out a GPS receiving process (in step ST201). That is, the
positioning means 41 receives the GPS signal sent from the GPS
receiver 1 and stores it, as GPS data, in a memory (not shown).
After that, the positioning means 41 returns the sequence to the
interrupted step and then ends the interruption process.
[0050] FIG. 3 is a flow chart showing an outline of a regular
process which is started at predetermined intervals. In this
regular process, the navigation apparatus determines whether the
program incorporated into the signal processing unit 4 needs to be
initialized first (in step ST301). The navigation apparatus
determines that the program needs to be initialized when the engine
of the vehicle is started and supply of power to the navigation
apparatus is then started. When, in this step ST301, determining
that the initialization of the program is needed, the navigation
apparatus then carries out the process of initializing the program
(in step ST302). That is, the program incorporated into the signal
processing unit 4 is initialized. In contrast, when, in step ST301,
determining that the initialization of the program is not needed,
the navigation apparatus skips the initialization process of step
ST302.
[0051] The navigation apparatus then carries out a positioning
process (in step ST303). Concretely, the positioning means 41
calculates the velocity of the vehicle and the distance which the
vehicle has traveled during each predetermined time interval on the
basis of the velocity signal sent from the velocity sensor 3. The
positioning means 41 also calculates the angle of turning which the
vehicle has made during each predetermined time interval on the
basis of the angular velocity signal sent from the angular velocity
sensor 2. After that, the positioning means 41 determines the
behavior of the vehicle, and, more specifically, calculates the
current position, traveling direction, velocity, etc. of the
vehicle (which are called the DR position, the DR direction, etc.),
and sends them, as well as the GPS data which are received from the
GPS receiver 1 and stored in the memory (i.e., a current position,
a traveling direction, a velocity, a GPS electric wave reception
state, etc.), to the road matching means 42 and unregistered road
detecting means 45 as the positioning data. The positioning means
41 also makes a sensor correction to the velocity signal sent from
the velocity sensor 3 and the angular velocity signal sent from the
angular velocity sensor 2. Concrete descriptions of the
determination of the behavior of the vehicle and sensor correction
are disclosed in, for example, Japanese Patent No. 3321096. So,
please refer to it if needed.
[0052] The navigation apparatus then carries out a road matching
process (in step ST304). That is, the road matching means 42
identifies the current position (referred to as the "M position")
of the vehicle on the basis of road data about a certain region
which is read from the road-map-data storage means 43, and the
positioning data indicating the behavior of the vehicle determined
by the positioning means 41. The road matching means 42 then
determines that the state of the identification of the current
position of the vehicle is the matching state when the road
matching means has identified only one current position of the
vehicle on a registered road, determines that the state of the
identification is the pending state when the road matching means
has selected one candidate from two or more candidates for the
current position of the vehicle each of which is defined as
coordinates on a registered road and is judging the selected
candidate, or determines that the state of the identification is
the free state when the road matching means identifies the current
position of the vehicle as being out of any registered road, and
sends matching result data indicating the determined state of the
identification to the display control means 44 and unregistered
road detecting means 45. A concrete description of the process of
identifying the current position of the vehicle is disclosed in,
for example, JP,2000-346663,A. So, please refer to it if
needed.
[0053] The navigation apparatus then carries out an unregistered
road detection process (in step ST305). In this unregistered road
detection process, the navigation apparatus carries out a process
of detecting an unregistered road using the unregistered road
detecting means 45. The details of this unregistered road detection
process will be explained below. The navigation apparatus then
checks to see whether an unregistered road has been detected (in
step ST306). When, in this step ST306, determining that the
unregistered road detecting means has detected an unregistered
road, the navigation apparatus carries out a road data generation
process (in step ST307). That is, the road data generating means 46
generates road data about an unregistered road from the coordinates
of the unregistered road detected by the unregistered road
detecting means 45, and adds the generated road data to the road
map data stored in the road-map-data storage means 43. After that,
the navigation apparatus changes a flag indicating whether an
unregistered road has been detected to "no detection." When, in
above-mentioned step ST306, determining that the unregistered road
detecting means has detected no unregistered road, the navigation
apparatus skips the road data generation process of step ST307.
[0054] The navigation apparatus then carries out a display control
process (in step ST308). That is, the display control means 44
creates display data about a display in which the current position
of the vehicle identified by the road matching means 42 and other
information about the vehicle, including a route, a guide map, etc.
which are created through processing not shown, are superimposed on
the road map data read from the road-map-data storage means 43, and
sends the display data to the display unit 5. After that, the
navigation apparatus ends the regular processing.
[0055] Next, the details of the unregistered road detection process
carried out in above-mentioned step ST305 will be explained with
reference to a flow chart shown in FIG. 4 and explanatory diagrams
shown in FIGS. 5 to 9.
[0056] In the unregistered road detection process, the unregistered
road detecting means 45 checks to see whether a detection start
point (i.e., a point A) for an unregistered road has not been set
up yet (in step ST401). In this step ST401, when determining that
the detection start point (i.e., the point A) has not been set up
yet, the unregistered road detecting means carries out a vehicle
departure judgment process (in step ST402). In this vehicle
departure judgment process, the unregistered road detecting means
45 determines that the vehicle has started departing from any
registered road when the identification state indicated by the
matching result data sent from the road matching means 42 changes
from the matching state to the free state. Otherwise, the
unregistered road detecting means 45 does not determine that the
vehicle has started departing from any registered road.
[0057] On the basis of the judgment result in above-mentioned step
ST402, the unregistered road detecting means 45 then checks to see
whether the vehicle has started departing from any registered road
(in step ST403). In this step ST403, when determining that the
vehicle has started departing from any registered road, the
unregistered road detecting means 45 creates a history of
candidates for the detection start point for an unregistered road
(in step ST406). That is, the unregistered road detecting means 45
records, as a history of candidates for the detection start point
for an unregistered road, the output of the positioning means 41
and the output of the road matching means 42 every time when the
vehicle travels a certain distance so that the unregistered road
detecting means 45 can carry out a detection start point setting
process in step ST404 when the matching result data sent from the
road matching means 42 indicates that the identification state is
the matching state, as shown in FIG. 6A. Historical data recorded
as the history of candidates for the detection start point for an
unregistered road include a start point history ID, times,
positioning results, and road matching results, as shown in FIG.
6B. The position, direction, velocity, and traveled distance, angle
of turning of the vehicle, the GPS electric wave reception state,
etc., which are sent, as the positioning data, from the positioning
means 41, are included in the positioning results. The position and
direction of the vehicle, road matching state, road data, etc.,
which are sent, as the matching result data, from the road matching
means 42, are included in the road matching results. After that,
the navigation apparatus ends the unregistered road detection
process.
[0058] In contrast, when, in above-mentioned step ST403,
determining that the vehicle has started departing from any
registered road, the unregistered road detecting means 45 sets up
the detection start point for an unregistered road (in step ST404).
That is, the unregistered road detecting means 45 defines, as the
detection start point, a point A which is located backwardly at a
predetermined distant or longer from a certain point (i.e., a
vehicle departure point at which the vehicle started departing from
a registered road, or a point A'') on the registered road at which
the vehicle was traveling at a time when the identification state
was the matching state (actually, an incorrect matching state) just
before the identification state has changed to the free state, as
shown in FIG. 5. The navigation apparatus then initializes a
traveling path (in step ST405). That is, the unregistered road
detecting means 45 generates a start point and interpolation points
of a traveling path from the history of candidates for the
detection start point created in step ST406. The start point is a
point corresponding to the detection start point (i.e., the point
A), and each interpolation point is a point which satisfies
conditions shown in FIG. 7A which will be mentioned below. After
that, the navigation apparatus ends the unregistered road detection
process.
[0059] When, in above-mentioned step ST401, determining that the
detection start point (i.e., the point A) for an unregistered road
has been set up, the unregistered road detecting means 45 then
creates a traveling path (in step ST407). That is, when the vehicle
has traveled a predetermined distance or longer from the previous
interpolation point on the already-created traveling path and has
turned a predetermined angle or more, as shown in FIG. 7A, the
unregistered road detecting means 45 sets up a new interpolation
point using the positioning data from the positioning means 41 and
the matching result data from the road matching means 42. Thus, by
setting up interpolation points in turn, the unregistered road
detecting means creates a traveling path as shown by a dashed line
in FIG. 7B. As shown in FIG. 7C, the unregistered road detecting
means creates a traveling path by carrying out a polygonal-line
approximation process of connecting straight lines which connect
the start point N1 and the interpolation points N2 to N6 in turn
with one another.
[0060] The navigation apparatus then carries out a detection end
judgment process (in step ST408). That is, the unregistered road
detecting means 45 judges whether to end the detection process when
the matching state indicated by the matching result data sent from
the road matching means 42 has continued while the vehicle has
traveled a predetermined distance or longer. Otherwise, the
unregistered road detecting means 45 does not determine that it
should the detection process. On the basis of the judgment result
in above-mentioned step ST408, the unregistered road detecting
means 45 then checks to see whether or not the detection process
should be ended (in step ST409). When, in this step ST409,
determining that the detection process should be ended, the
unregistered road detecting means 45 ends the unregistered road
detection process.
[0061] In contrast, when, in this step ST409, not determining that
the unregistered road detecting means 45 should end the detection
process, it then sets up a detection end point (in step ST410).
That is, the unregistered road detecting means 45 sets up, as the
detection end point (i.e., a point B), the coordinates of the
current position of the vehicle on a registered road which the road
matching means 42 has identified, as shown in FIG. 8. FIG. 8 shows
a positional relationship between the detection end point (i.e.,
the point B) for an unregistered road and points where the state of
the identification carried out by the road matching means 42 has
changed in turn from the free state to the pending state, and then
to the matching state.
[0062] The navigation apparatus then performs a coordinate
transformation on the coordinates of the traveling path (in step
ST411). That is, as shown in FIG. 9A, the unregistered road
detecting means 45 performs parallel translation on the traveling
path so that the start point of the traveling path containing the
unregistered road has coordinates which match with the coordinates
of the detection start point (i.e., the point A) for the
unregistered road, and, after that, carries out an affine
transformation (expansion and contraction, and rotational movement)
so that the end point of the traveling path has coordinates which
match with the coordinates of the detection end point (i.e., the
point B) for the unregistered road. As a result, a traveling path
including the unregistered road as shown in FIG. 9B can be
generated. The affine transformation is carried out according to
the following equations. If each of the amount of movement in the
coordinate system, the expansion and contraction coefficient, and
the rotation angle of the traveling path, which are caused by the
affine transformation, falls within a predetermined range which is
estimated from the accuracy of the current position of the vehicle,
the accuracy of correction of the angular velocity sensor 2, and
the accuracy of correction of the velocity sensor 3, it can be
considered that the detection of the unregistered road has
succeeded. In contrast, if either one of the amount of movement in
the coordinate system, expansion and contraction coefficient, and
rotation angle of the traveling path, which are caused by the
affine transformation, does not fall within the predetermined
range, it can be considered that the detection of the unregistered
road has ended in failure.
S=|P.sub.F2-P.sub.0|/|P.sub.F1-P.sub.0|
.alpha.=tan.sup.-1{(y.sub.F2-y.sub.0)/(x.sub.F2-x.sub.0))}-tan.sup.-1{(y-
.sub.F1-y.sub.0)/(x.sub.F1-x.sub.0)} [rad]
x.sub.N2=S{(x.sub.N1-x.sub.0)cos .alpha.-(y.sub.N1-y.sub.0)sin
.alpha.}+x.sub.0
y.sub.N2=S{(x.sub.N1-x.sub.0)sin .alpha.+(y.sub.N1-y.sub.0)cos
.alpha.}+y.sub.0
where S: the expansion-and-contraction coefficient, .alpha.: the
rotation angle (having a positive sign when expressed in a
clockwise direction, and a negative sign when expressed in an
anticlockwise direction) [rad] P.sub.0: the start point (x.sub.0,
y.sub.0) P.sub.F1, P.sub.F2: the yet-to-be-corrected end point
(x.sub.F1, y.sub.F1), and the corrected end point (x.sub.F2,
y.sub.F2) x.sub.0, y.sub.0: the x and y coordinates of the start
point [m] x.sub.F1, y.sub.F1: the x and y coordinates of the
yet-to-be-corrected end point [m] x.sub.F2, y.sub.F2: the x and y
coordinates of the corrected end point [m]
[0063] The unregistered road detecting means 45 then detects
sections in each of which the traveling path and a registered road
overlaps (in step ST412). That is, the unregistered road detecting
means 45 projects an arbitrary point on a registered road (shown by
a solid line) onto straight lines which connect among the
interpolation points of the traveling path, as shown in FIG. 9B, on
which an affine transformation has been performed, by tracing the
traveling path from the point A along the traveling direction, and
also tracing the traveling path from the point B along the
direction opposite to the traveling direction, as shown in FIG. 9C,
determines whether or not the distance between the arbitrary point
and the traveling path is equal to or shorter than a predetermined
value, and determines that the traveling path (shown by a dashed
line) overlaps the registered road when the distance between the
arbitrary point and the traveling path is equal to or shorter than
the predetermined value. The unregistered road detecting means 45
thus deletes any section of the traveling path which overlaps a
registered road. The unregistered road detecting means 45 then
detects points where the upstream and downstream sections of the
traveling path which overlap registered roads, respectively, are
disconnected from the remaining traveling path, and defines them as
a vehicle departure point (i.e., a point A') and a vehicle return
point (i.e., a point B'), respectively. After that, when the length
of the remaining traveling path, i.e., the distance between the
vehicle departure point (or the point A') and the vehicle return
point (or the point B') is equal to or longer than a predetermined
distance, as shown in FIG. 9D, the unregistered road detecting
means 45 determines that the detection of the unregistered road has
succeeded and detects the coordinates of the unregistered road from
the coordinates of the remaining traveling path. In contrast, when
the length of the remaining traveling path is shorter than the
predetermined distance, the unregistered road detecting means 45
determines that the detection of the unregistered road has ended in
failure. Furthermore, the unregistered road detecting means 45 can
be so constructed as to determine whether there is similarity
between the shape of each of the registered roads and that of the
traveling path and whether there is consistency between the
location of each of the registered roads and that of the traveling
path so as to detect the point A' and/or point B' when being unable
to trace the registered roads up to the point A' and/or point
B'.
[0064] On the basis of both the judgment results in above-mentioned
steps ST411 and ST412, the unregistered road detecting means 45
then checks to see whether the detection of the unregistered road
has succeeded (in step ST413). When, in this step ST413,
determining that both the judgment results indicate that the
detection of the unregistered road has succeeded, the unregistered
road detecting means 45 calculates the coordinates of the
unregistered road (in step ST414). In contrast, when, in step
ST413, determining that at least one of the judgment results
indicates that the detection of the unregistered road has ended in
failure, the unregistered road detecting means 45 skips the process
of step ST414. The unregistered road detecting means 45 then clears
the detection start point and detection end point for the
unregistered road (in step ST415). As a result, the unregistered
road detecting means 45 places its state to a state in which it can
detect another unregistered road. After that, the unregistered road
detecting means 45 ends the unregistered road detection
process.
[0065] As previously explained, the navigation apparatus in
accordance with embodiment 1 of the present invention defines, as a
detection section for an unregistered road, a section between two
points respectively on registered roads in which the state of the
identification of the current position of the vehicle is the
matching state, the two points being respectively located before
and behind sections in which the state of the identification is the
free state, that is, a section between a detection start point (or
a point A) and a detection end point (or a point B), performs a
coordinate transformation on a traveling path between the two
points which is estimated regardless of processing carried out by
the road matching means 42 so that the start point and end point of
the traveling path have coordinates which match with the
coordinates of the two points, respectively, determines that
sections of the traveling path which are similar to parts of the
registered roads, respectively, and which are running in parallel
with the parts of the registered roads overlap the registered
roads, respectively, and removes the sections of the traveling path
from the traveling path, and then detects the coordinates of the
unregistered road from the remaining traveling path. Therefore, the
navigation apparatus in accordance with embodiment 1 of the present
invention can improve the probability of succeeding in the
detection of an unregistered road, and can detect the coordinates
of the unregistered road with a higher degree of accuracy. As a
result, the navigation apparatus in accordance with embodiment 1 of
the present invention can carry out route searching and route
guidance on the basis of the road data including data about
unregistered roads.
[0066] In accordance with a prior art navigation apparatus, when
the vehicle equipped with the navigation apparatus enters a bypass
which is an unregistered road from a main line, the current
position of the vehicle may continue to be identified as being on
the main line, and the identified current position of the vehicle
may be amended so that it is on the bypass after the current
position of the vehicle is greatly distant from the actual current
position of the vehicle on the bypass. Therefore, even if such a
prior art navigation apparatus starts detection of an unregistered
road immediately after the vehicle has departed from a main line,
it may detect, as a vehicle departure point, a position which is
distant from the position where the vehicle has departed from the
main line actually. In contrast, the navigation apparatus according
to embodiment 1 starts detection of an unregistered road from a
point A which is backwardly at a predetermined distance from the
coordinates of a point on a registered road at which the vehicle
was traveling immediately before the identification state shown by
the matching result data from the road matching means 42 has
changed from the matching state to the free state. Therefore, even
if the road matching means 42 continues to incorrectly identify the
current position of the vehicle as being on a registered road
although the vehicle has already begun to travel along an
unregistered road, the navigation apparatus according to embodiment
1 can detect the point where the unregistered road is connected to
the registered road, i.e., the vehicle departure point (or the
point A') correctly.
[0067] In addition, in the navigation apparatus in accordance with
this embodiment 1, when it is required of the road matching means
42 that the matching state should show long continuity so that
incorrect detection of a traveling path including an unregistered
road section is not carried out, because the setup of the detection
start point (point A) or the detection end point (point B) is
delayed, a long traveling path which overlaps registered roads is
created, and the points of an unregistered road connected to the
registered roads are found incorrectly when the coordinates of the
unregistered road are determined from the created traveling path,
sections of the traveling path which overlap the registered roads
are removed from the traveling path. As a result, even if the
vehicle travels along a traveling path including long registered
road sections and an unregistered road section, the navigation
apparatus can easily detect sections of the traveling path which
overlap the registered roads and the vehicle departure point (point
A') and the vehicle return point (point B') where the unregistered
road is connected to the registered roads, respectively.
Furthermore, because the navigation apparatus can set up points A
and B where the road matching means is securely placed in the
matching state on registered roads which are distant from the
points A' and B' where the unregistered road are connected to the
registered roads, respectively, the navigation apparatus can
improve the probability of succeeding in the detection of the
unregistered road.
Embodiment 2
[0068] In the navigation apparatus according to above-mentioned
embodiment 1, when the vehicle passes through an unregistered
tunnel while an error occurs in the bias of the angular velocity
sensor 2, any bias drift cannot be corrected for on the basis of
the GPS signal from the GPS receiver 1 and the road data read from
the road-map-data storage means 43. Therefore, in such a case, an
error of the traveling direction of the vehicle and an error of the
position of the vehicle increase gradually, and, when the GPS
signal is acquired from the GPS receiver 1 immediately after the
vehicle has passed through an unregistered tunnel, the current
position of the vehicle is amended on the basis of this GPS signal.
In this case, because a "position jump" occurs and the traveling
path is then separated into portions immediately after the vehicle
has passed through the tunnel, as shown in FIG. 10A, the generation
of road data using the coordinates of the traveling path in the
state where the traveling path is separated into portions, the
shape and coordinates of the unregistered road on the basis of the
road data will be inaccurately determined.
[0069] To solve this problem, a navigation apparatus in accordance
with this embodiment 2 is so constructed as to be able to
accurately detect the coordinates of an unregistered road from a
traveling path of the vehicle even if the unregistered road
includes a continuation section in which GPS electric waves are
shielded, like a tunnel, in the course thereof, and the navigation
apparatus makes a position correction to the traveling path so that
the traveling path becomes discontinuous immediately after the
vehicle has passed through the continuation section in which GPS
electric waves are shielded.
[0070] In the navigation apparatus according to this embodiment 2,
an unregistered road detecting means 45 records the traveled
distance of the vehicle and the shield state of GPS electric waves
(or a GPS electric wave reception state) while associating them
with the traveling path of the vehicle, and, immediately after the
vehicle has passed through a continuation section in which GPS
electric waves are shielded, compares the amount of updates of the
coordinates of the traveling path with the traveled distance of the
vehicle which is calculated on the basis of a velocity signal from
a velocity sensor 3 so as to check the continuity of the traveling
path. When the difference between the amount of updates of the
coordinates of the traveling path and the traveled distance of the
vehicle is equal to or larger than a predetermined value, as shown
in FIG. 10A, the unregistered road detecting means 45 determines
that the traveling path has been separated into portions. As shown
in FIG. 10B, the unregistered road detecting means 45 then carries
out a correction process of performing a coordinate transformation
on only an upstream one of the portions into which the traveling
path has been separated by defining, as the center of rotation of
an affine transformation, the entrance point of the tunnel first,
so as to connect the upstream portion and a downstream one of the
portions into which the traveling path has been separated into a
single traveling path. After that, the unregistered road detecting
means 45 performs a coordinate transformation on the whole
traveling path by defining, as the center of rotation of an affine
transformation, a point A so that the start point and end point of
the whole traveling path have coordinates which match with the
coordinates of a detection start point (i.e., the point A) and
those of an end detection point (i.e., a point B), respectively, as
shown in FIG. 10C. After that, the unregistered road detecting
means 45 calculates the coordinates of the unregistered road
through the same processing as that explained in embodiment 1.
[0071] As previously explained, even if the accuracy of position
degrades when the vehicle travels through a section in which GPS
electric waves are shielded and the traveling path is separated
into portions, the navigation apparatus in accordance with
embodiment 2 of the present invention partially performs a
coordinate transformation only on an upstream separated section
first so as to connect the separated upstream section and a
remaining section into a single traveling path, and, after that,
performs a coordinate transformation on the whole traveling path so
that the whole traveling path agrees with the coordinates of a
registered road between the detection start point (point A) and the
end detection point (point B). Therefore, the navigation apparatus
in accordance with embodiment 2 of the present invention can
improve the probability of succeeding in the detection of an
unregistered road at a time when the vehicle has traveled a section
in which GPS electric waves are shielded, and the accuracy of the
coordinates of the unregistered road.
Embodiment 3
[0072] As shown in FIG. 11, even if the vehicle travels an
identical road several times, there is a possibility that the
coordinates of the traveling path of the vehicle have variations
resulting from errors in the velocity sensor 3, the angular
velocity sensor 2, and the GPS receiver 1, and the coordinates of a
vehicle return point (or a point B') where an unregistered road is
connected to a registered road have an error range extending in the
direction of the registered road, as shown in FIG. 12. To solve
this problem, in the navigation apparatus according to embodiment
1, the unregistered road detecting means 45 defines, as the point
B, the coordinates of the current position of the vehicle which the
road matching means 42 has identified as being on a registered road
in step ST410 of FIG. 4, as to a timing of setting up the detection
end point (or the point B) by means of the unregistered road
detecting means 45.
[0073] In contrast, in a navigation apparatus according to this
embodiment 3, when a vehicle equipped with the navigation apparatus
has made a right or left turn, an unregistered road detecting means
45 sets up a detection end point (or a point B) if the matching
state has been continuing while the vehicle has been traveling a
predetermined distance or longer along a registered road running in
a direction before the vehicle has made the right or left turn, and
the matching state will continue while the vehicle will be
traveling a predetermined distance or longer along a registered
road running in a different direction after the vehicle has made
the right or left turn.
[0074] Thus, when the matching state had continued while the
vehicle had traveled a predetermined distance or longer before the
vehicle made a right or left turn, and, after that, the matching
state has continued while the vehicle has traveled a predetermined
distance or longer after the vehicle made the right or left turn,
the navigation apparatus in accordance with this embodiment 3
defines, as the detection end point (or the point B), the
coordinates of the current position of the vehicle on a registered
road. Therefore, the navigation apparatus can accurately detect the
coordinates of any registered road to which the unregistered road
is connected even if the coordinates of the traveling path have
variations as shown in FIG. 11.
Embodiment 4
[0075] In the navigation apparatus according to above-mentioned
embodiment 1, when an error occurs in the traveling direction of
the vehicle estimated by the positioning means 41, the road
matching means 42 judges easily and incorrectly that the vehicle
has departed from a registered road, and, as a result, the
frequency with which an unregistered road is created incorrectly
increases. Thus, when the frequency with which an unregistered road
is created incorrectly increases, the user needs to delete
information about such an unregistered road from the navigation
apparatus frequently and if the user is later for the deletion of
the information, there arises a case in which any further
unregistered road cannot be registered because of a lack of the
storage capacity of the road-map-data storage means 43 when the
user desires to add an unregistered road truly. A navigation
apparatus according to this embodiment 4 is provided in order to
solve this problem, and is so constructed as not to determine that,
even if an error occurs in the traveling direction of the vehicle
estimated by a positioning means 41 while the vehicle travels along
a registered road, the vehicle has traveled along a road other than
registered roads, thereby preventing incorrect detection of any
traveling path including an unregistered road.
[0076] That is, in the navigation apparatus according to embodiment
1, as to a timing of setting the detection end point (or the point
B) by means of the unregistered road detecting means 45, the
unregistered road detecting means 45, in step ST402 of FIG. 4,
determines that the vehicle has started departing from a registered
road when the identification state indicated by the matching result
data from the road matching means 42 changes from the matching
state to the free state, and, in step ST404, defines, as the
detection start point, a point A which is located backwardly at a
predetermined distant or longer from a point on the registered road
at which the vehicle was traveling at a time when the
identification state was the matching state immediately before the
identification state has changed to the free state, i.e., a vehicle
departure point (or a point A'') on the registered road.
[0077] In contrast, in the navigation apparatus according to
embodiment 4, when matching result data from a road matching means
42 indicates that the state of the identification of the current
position of the vehicle is a matching state, an unregistered road
detecting means 45 performs a coordinate transformation on a
traveling path having a predetermined distance, as shown in FIG.
13A, and calculates the distance between each of a DR position and
interpolation points, and a corresponding one of matched positions
on a registered road which respectively correspond to the DR
position and interpolation points from the coordinate-transformed
traveling path, as shown in FIG. 13B. The unregistered road
detecting means 45 then compares the calculated distance with the
width of the registered road so as to check to see whether the
traveling path falls within a region defined by the road width,
and, when determining that the traveling path does not fall within
the region defined by the road width, defines, as the vehicle
departure point (or the point A''), the coordinates of the current
position of the vehicle, and further defines, as a detection start
point A, a point on the registered road which is located backwardly
at a predetermined distant or longer from the point A''.
[0078] As previously explained, the navigation apparatus according
to embodiment 4 is so constructed as to perform a coordinate
transformation on a traveling path having a predetermined distance
to judge whether the coordinate-transformed traveling path falls
within a region defined by the width of a registered road along
which the vehicle is traveling, and to set up the vehicle departure
point (or the point A'') and the detection start point (or the
point A) on the basis of this judgment result. Therefore, the
navigation apparatus according to embodiment 4 can detect an actual
vehicle departure point (or a point A') with a higher degree of
accuracy. Furthermore, even if the traveling direction of the
vehicle differs from the direction of a registered road due to an
error which occurs in the traveling direction of the vehicle
estimated by the positioning means 41 from a lack of the correction
of errors of a velocity sensor 3 and an angular velocity sensor 2
and errors of a GPS receiver 1 when the vehicle is traveling along
the registered road, the navigation apparatus according to
embodiment 4 determines that the identification state is the
matching state if the traveling path falls within a region defined
by the width of the registered road. Therefore, the navigation
apparatus according to embodiment 4 can decrease the frequency with
which an unregistered road is created incorrectly, and can also
reduce the number of times that the user has to delete information
about an unregistered road created incorrectly.
Embodiment 5
[0079] In the navigation apparatus according to above-mentioned
embodiment 1, as to a timing of setting the detection end point (or
the point B) by means of the unregistered road detecting means 45,
the unregistered road detecting means 45, in step ST408 of FIG. 4,
determines that it should end the detection of an unregistered road
when the road matching means 42 has continued to be placed in the
matching state while the vehicle has been traveling a predetermined
distance or longer, and, in step ST410, defines, as the point B,
the coordinates of the current position of the vehicle which the
road matching means 42 has identified as being on a registered
road.
[0080] In contrast, in a navigation apparatus according to
embodiment 5, as shown in FIG. 14, a condition that there must be
similarity between the shape of the traveling path of the vehicle
and that of a registered road over a predetermined distance or
longer while the state of the identification of the current
position of the vehicle is a matching state is added to conditions
for a judgment process in step ST408 of judging whether the
detection of an unregistered road should be ended. When this
condition is satisfied, a road matching means 42 defines, as a
detection end point (or a point B), the coordinates of the current
position of the vehicle which it has identified as being on the
registered road.
[0081] In the navigation apparatus in accordance with this
embodiment 5, even if the unregistered road detecting means 45
carries out map matching incorrectly so as to draw the current
position of the vehicle which it has estimated as being in the
vicinity of a registered road toward the registered road when the
road matching means 42 shows that the state of the identification
of the current position of the vehicle is a free state, the
unregistered road detecting means 45 defines, as the detection end
point (or the point B), the coordinates of the current position of
the vehicle on a registered road about which it has recognized that
there is similarity between the shape of the traveling path and
that of the registered road and there is consistency between the
location of the traveling path and that of the registered road over
a predetermined distance or longer. Therefore, the navigation
apparatus can carry out detection of the coordinates of any
registered road to which the unregistered road is connected.
Embodiment 6
[0082] In the navigation apparatus according to above-mentioned
embodiment 1, as to a timing of setting the detection end point (or
the point B) by means of the unregistered road detecting means 45,
the unregistered road detecting means 45, in step ST408 of FIG. 4,
determines that it should end the detection of an unregistered road
when the road matching means 42 has continued to be placed in the
matching state while the vehicle has been traveling a predetermined
distance or longer, and, in step ST410, defines, as the point B,
the coordinates of the current position of the vehicle which the
road matching means 42 has identified as being on a registered
road.
[0083] In contrast, in a navigation apparatus according to
embodiment 6, as shown in FIG. 15A, when the state of the
identification of the current position of the vehicle changes in
turn from a matching state to a free state, to a pending status,
and then to the matching state while the vehicle travels along a
registered road before and behind passing through an unregistered
road section, a road matching means 42 defines, as a detection end
point (or a point B), the coordinates of the current position of
the vehicle which it has identified as being on a registered road
on the condition that there is consistency between the shape and
coordinates of a traveling path created from a point A on a
registered road along which the vehicle traveled before entering
the unregistered road section and those of a registered road along
which the vehicle has traveled after exiting the unregistered road
section within a specified positional limit (e.g., L1, L2, and beta
which are shown in FIG. 15B have a predetermined relation among
them) which is estimated from a precision in the distance obtained
from a signal of a velocity sensor 3 or a precision in the angle of
turning obtained from a signal of an angular velocity sensor 2.
[0084] In the navigation apparatus in accordance with this
embodiment 6, even if the unregistered road detecting means 45
carries out map matching incorrectly so as to draw the current
position of the vehicle which it has estimated as being in the
vicinity of a registered road toward the registered road when the
road matching means 42 shows that the identification state is the
free state, the unregistered road detecting means 45 defines, as
the detection end point (or the point B), the coordinates of the
current position of the vehicle on a registered road about which it
has recognized that there is similarity between the shape of the
traveling path and that of the registered road and there is
consistency between the location of the traveling path and that of
the registered road over a predetermined distance or longer.
Therefore, the navigation apparatus can carry out detection of the
coordinates of any registered road to which the unregistered road
is connected.
Embodiment 7
[0085] In the navigation apparatus according to above-mentioned
embodiment 1, in a case in which a position error of more than a
predetermined value occurs in the traveling direction of the
vehicle while the vehicle is traveling along a straight line
section of a registered road, if, after that, the vehicle makes a
right or left turn at an intersection in the registered road, the
state of the identification of the current position of the vehicle
changes from the matching state to the free state and incorrect
detection of an unregistered road is started because the traveling
direction of the vehicle which has been estimated at a location
which is assumed to be different from the intersection changes. As
a result, the frequency with which an unregistered road is created
incorrectly increases. Thus, when the frequency with which an
unregistered road is created incorrectly increases, the user needs
to delete information about such an unregistered road from the
navigation apparatus frequently and if the user is later for the
deletion of the information, there arises a case in which any
further unregistered road cannot be registered because of a lack of
the storage capacity of the road-map-data storage means 43 when the
user desires to add an unregistered road truly. A navigation
apparatus according to this embodiment 7 is provided in order to
solve this problem, and is so constructed as to prevent
automatically creation of unnecessary road data at a time when the
vehicle makes a right or left turn even if a position error occurs
in the traveling direction of the vehicle while the vehicle is
traveling along a straight line section of a registered road.
[0086] That is, in the navigation apparatus according to
above-mentioned embodiment 1, as to creation of road data about an
unregistered road from the traveling path from which portions which
overlap registered roads are deleted, the unregistered road
detecting means 45, in step ST412 of FIG. 4, deletes any portion of
the traveling path which overlaps a registered road, and, when the
length of the remaining traveling path is equal to or longer than a
predetermined distance, determines that the detection of the
unregistered road has succeeded and then detects the coordinates of
the unregistered road from the coordinates of the remaining
traveling path, whereas when the length of the remaining traveling
path is shorter than the predetermined distance, the unregistered
road detecting means determines that the detection of the
unregistered road has ended in failure.
[0087] In contrast, in a navigation apparatus according to
embodiment 7, in a case in which at a location where an
intersection exists in the vicinity of a point where the vehicle
has made a right or left turn, as shown in FIG. 16, the state of
the identification of the current position of the vehicle which is
indicated by matching result data from a road matching means 42
changes from a matching state to a free state according to the
right-turn or left-turn behavior of the vehicle, and, after that,
returns to the matching state via a pending state, when a
coordinate transformation (parallel translation, rotation,
expansion and contraction) is performed on the traveling path
within limits of an amount of movement in a coordinate system, an
expansion-and-contraction coefficient and a rotation angle of the
traveling path which are estimated from the accuracy of the current
position of the vehicle, the accuracy of correction of an angular
velocity sensor 2, and the accuracy of correction of a velocity
sensor 3, an unregistered road detecting means 45 determines that
the identification state has changed from the matching state to the
free state according to the right-turn or left-turn behavior of the
vehicle because of a position error which has occurred in the
traveling direction of the vehicle when the vehicle has been
traveling along the registered road, and cancels the detection of
an unregistered road.
[0088] The navigation apparatus according to this embodiment 7 is
so constructed as to determine whether or not a coordinate
transformation (expansion and contraction) is performed on the
traveling path within limits of the expansion-and-contraction
coefficient of the traveling path which is estimated from the
accuracy of the current position of the vehicle and the accuracy of
correction of the velocity sensor 3. Therefore, it becomes
difficult for the navigation apparatus to detect an unnecessary
unregistered road. As a result, the user does not need to perform
any operation of deleting an unnecessary unregistered road
frequently.
Embodiment 83
[0089] In prior art navigation apparatus, in order to prevent
incorrect matching, an interconnection between a highway and a
local street is limited to a highway interchange (abbreviated as
"IC" from here on), for example. For this reason, in a case in
which a highway IC is an unregistered road, the state of the
identification of the current position of the vehicle may not
change to a matching state, but may remain being a pending state
even if the current position of the vehicle is identified as being
on a local street after the vehicle has departed downward from a
highway toward the local street through the unregistered highway
IC. In this case, because the setup of the detection end point for
the unregistered road is delayed and hence portions of the
traveling path which overlap registered roads become long, it
becomes difficult to carry out detection of points where the
unregistered road is respectively connected to the registered
roads. A navigation apparatus in accordance with this embodiment 8
is made in order to solve this problem, and is so constructed as to
detect an unregistered road even if a highway IC is the
unregistered road.
[0090] That is, in the navigation apparatus according to
above-mentioned embodiment 1, as to a timing of setting the
detection end point (point B) for an unregistered road using the
unregistered road detecting means 45, the unregistered road
detecting means 45, in step ST408 of FIG. 4, determines that it
should end the detection of an unregistered road when the road
matching means 42 continues to be placed in the matching state
while the vehicle is traveling a predetermined distance or longer,
and the road matching means 42, in step ST410, defines, as the
point B, the coordinates of the current position of the vehicle
which it has identified as being on a registered road.
[0091] In contrast, in a navigation apparatus according to
embodiment 8, in a case, as shown in FIG. 17, in which when the
vehicle has passed through an unregistered highway IC, and has
entered a local street from a highway or has entered a highway from
a local street, a road matching means 42 remains being placed in a
pending state and therefore has not switched to any other state
even if the vehicle has traveled a predetermined distance or longer
along a registered road after passing through the highway IC, if
the traveling path for which detection was started from a detection
start point (or a point A) on another registered road along which
the vehicle was traveling before the vehicle has entered the
highway IC overlaps the registered road for which the
identification state is the pending state while the vehicle is
traveling a predetermined distance or longer, or if there is a
registered road running in parallel with and in the vicinity of the
traveling path of the vehicle, an unregistered road detecting means
45 sets up a detection end point (or a point B) on the registered
road.
[0092] The navigation apparatus in accordance with this embodiment
8 can thus generate road data indicating an unregistered highway IC
without changing the processing method and characteristics of the
road matching means 43 of limiting an interconnection between a
highway and a local street to a highway IC, for example, in order
to prevent the navigation apparatus itself from incorrectly
identifying the current position of the vehicle as being on a
registered road.
Embodiment 9
[0093] When a highway IC or a highway junction (abbreviated as
"JCT" from here on) is an unregistered road, the road matching
means 42 is late for a setup of the detection end point for the
traveling path because the vehicle will travel along a registered
road with the road matching means being placed in the pending state
without changing its identification state to the matching state
even if the registered road which the vehicle will travel after
traveling through the unregistered road overlaps the coordinates of
the traveling path or there is a registered road running in
parallel with and in the vicinity of the traveling path.
Furthermore, when a registered road of the same road type which the
road matching means 42 can easily connect to the traveling path is
running in parallel with and in the vicinity of the traveling path,
the road matching means incorrectly matches the current position of
the vehicle onto the registered road. A navigation apparatus in
accordance with this embodiment 9 is made in order to solve this
problem, and is so constructed as to, even if a highway IC or a
highway JCT is an unregistered road, judges the validity of
connection between a local street and a highway, the validity of
connection between local streets, and the validity of connection
between highways according to the travel of the vehicle to detect
the unregistered road.
[0094] That is, in the navigation apparatus according to
above-mentioned embodiment 1, as to a timing of setting the
detection end point (point B) for an unregistered road using the
unregistered road detecting means 45, the unregistered road
detecting means 45, in step ST408 of FIG. 4, determines that it
should end the detection of an unregistered road when the road
matching means 42 continues to be placed in the matching state
while the vehicle is traveling a predetermined distance or longer,
and the road matching means 42, in step ST410, defines, as the
point B, the coordinates of the current position of the vehicle
which it has identified as being on a registered road.
[0095] In contrast, a navigation apparatus according to embodiment
9 retrieves road data about a certain region in the vicinity of the
traveling path for which detection was started from a point A on a
registered road along which the vehicle was traveling before the
vehicle has entered an unregistered road from a road-map-data
storage means 43, as shown in FIG. 18, and, when being able to
determine that both a highway and a local street are running in
parallel with and in the vicinity of the traveling path, suspends
the judgment irrespective of their road types and the state of the
identification of the current position of the vehicle until there
causes a remarkable significant difference between the similarity
between the shape of the traveling path and that of the highway and
the similarity between the shape of the traveling path and that of
the local street, or between the consistency between the location
of the traveling path and that of the highway and the consistency
between the location of the traveling path and that of the local
street, and, after that, sets up a detection end point (or a point
B) on a registered road which the navigation apparatus has
recognized has consistency with the traveling path when a
significant difference appears between the similarities or
consistencies.
[0096] In the navigation apparatus in accordance with this
embodiment 9, in a case in which a highway IC or a highway JCT is
an unregistered road, when a registered road having the same road
type as another registered road which the vehicle has traveled
before traveling the unregistered road is running in parallel with
the traveling path and in the vicinity of the current position of
the vehicle, the road matching means 42 may incorrectly match the
current position of the vehicle onto the registered road, though
the road matching means can detect a registered road which has a
shape which matches with the shape of the traveling path regardless
of the road type of the registered road even in this case.
Embodiment 10
[0097] If the driver stops the vehicle and turns off the engine of
the vehicle in order to, for example, take a rest while he or she
drives the vehicle along an unregistered road of a long distance,
the navigation apparatus according to either one of above-mentioned
embodiments cannot resume detecting the unregistered road after the
driver turns on the engine of the vehicle. A navigation apparatus
in accordance with this embodiment 10 is made in order to solve
this problem, and is so constructed as to be able to resume the
process of detecting an unregistered road after the engine of the
vehicle is turned on even if the engine of the vehicle is turned
off while the navigation apparatus detects a traveling path
including the unregistered road.
[0098] In the navigation apparatus in accordance with the
above-mentioned embodiment 1, no mention is made of a case in which
the engine of the vehicle is stopped while the navigation apparatus
sets up the detection start point (or the point A) for an
unregistered road and then detects the unregistered road. In
contrast, a navigation apparatus in accordance with this embodiment
10 is provided with a non-volatile memory (not shown), and, every
time when a predetermined time elapses or when the vehicle travels
a predetermined distance, stores various data about detection of an
unregistered road in the non-volatile memory, as well as
positioning data calculated by a positioning means 41 and matching
result data calculated by a road matching means 42. When then
determining that data indicating that the detection of an
unregistered road had been being carried out before the engine was
turned off is recorded in the non-volatile memory immediately after
the engine is turned on, the navigation apparatus determines that
there is no harm in resuming the detection of the unregistered road
and resumes the detection of the unregistered road if the vehicle
position which is received by a GPS receiver 1 after the engine is
turned on falls within a predetermined region around the vehicle
position which was detected before the engine was turned off. In
contrast, if the vehicle position which is received by the GPS
receiver 1 after the engine is turned on is out of the
predetermined region around the vehicle position which was detected
before the engine was turned off, the navigation apparatus
determines that the vehicle has been moved by a ferry or the like
while the engine of the vehicle is at rest and there is harm in
resuming the detection of the unregistered road, and stops the
detection of the unregistered road.
[0099] The navigation apparatus in accordance with this embodiment
10 can detect an unregistered road continuously even if the engine
is turned off and then turned on. Therefore, for example, even if
road data about a road having a length of more than tens of km is
not registered in the road map data, the navigation apparatus can
generate road data about the road.
Embodiment 11
[0100] A navigation apparatus in accordance with this embodiment 11
differs from the navigation apparatus in accordance with embodiment
1 in the operation of an unregistered road detecting means 45. The
navigation apparatus in accordance with this embodiment 11 has the
same structure as the navigation apparatus in accordance with
above-mentioned embodiment 1. Hereafter, the details of
unregistered road detection processing carried out by the
unregistered road detecting means 45 will be explained with
reference to an explanatory diagram shown in FIG. 19, and a flow
chart shown in FIGS. 20 and 21.
[0101] FIG. 19 is a diagram showing a transition
(A-D-E-F-H-I-J-K-L-N-O-Q-R-S) of the position of the vehicle
identified by a road matching means 42 when the vehicle travels
straightforward along a road (A-D-P-S) in which an unregistered
road section (D-P) exists at some midpoint of the road. In this
example, assume that the power supply of the navigation apparatus
was turned on when the vehicle reached the point A and the current
position of the vehicle is at the point S. In each of the sections
A-D, I-J, O-Q, and R-S on the registered road, the matching result
data indicates that the state of the identification of the current
position of the vehicle is a matching state, whereas in each of the
sections D-H and J-N, the matching result data indicates that the
state of the identification of the current position of the vehicle
is a free state. Each of the sections B-C and P-R on the registered
road is a section which is determined to have some candidates for
the current position of the vehicle by the road matching means 42.
The dotted line in the figure is a traveling path acquired by a
positioning means 41.
[0102] In unregistered road detection processing, the unregistered
road detecting means creates a traveling path first, as in the case
of step ST407 of above-mentioned embodiment 1 (in step ST501). The
unregistered road detecting means then checks to see whether the
matching result data outputted from the road matching means 42
indicates the matching state (in step ST502). When, in this step
ST502, judging that the matching result data does not indicate the
matching state, the unregistered road detecting means carries out a
vehicle departure determining process (steps ST511 to ST515) of
determining that the vehicle has departed from a registered road.
The details of this vehicle departure determining processing will
be explained below.
[0103] In contrast, when, in step ST502, judging that the matching
result data indicates the matching state, the unregistered road
detecting means carries out addition of a matching distance and
clearing of a free distance (in step ST503). That is, the
unregistered road detecting means adds a value calculated on the
basis of the positioning data from the positioning means 41 to the
matching distance showing a distance over which the matching state
continues, and sets the free distance showing a distance over which
the free state continues to zero.
[0104] The unregistered road detecting means then checks to see
whether or not an unregistered road detection flag is cleared (in
step ST504). When, in this step ST504, determining that the
unregistered road detection flag is cleared, the unregistered road
detecting means recognizes that the vehicle has been traveling
along a registered road, and then carries out a vehicle departure
judgment process (steps ST505 to ST510) of judging whether it is
possible that the vehicle has departed from the registered road.
The details of this vehicle departure judgment processing will be
mentioned below.
[0105] In contrast, when, in step ST504, judging that the
unregistered road detection flag is not cleared, the unregistered
road detecting means carries out a return judgment process (steps
ST516 to ST527) of recognizing that the vehicle has traveled along
an unregistered road, judging whether the vehicle has returned to a
registered road, determining the vehicle departure point and the
vehicle return point, calculating the coordinates of the
unregistered road section, and so on. The details of this return
judgment processing will be explained below.
(1) Vehicle Departure Judgment Processing
[0106] In the vehicle departure judgment processing, the
unregistered road detecting means carries out vehicle departure
judgment first, as in the case of step ST402 of above-mentioned
embodiment 1 (in step ST505). On the basis of the judgment result
in step ST505, the unregistered road detecting means checks to see
if it is possible that the vehicle has departed from a registered
road (in step ST506). When, in this step ST506, determining that it
is possible that the vehicle has departed from a registered road,
the unregistered road detecting means carries out a process of
adding a candidate for the vehicle departure point (in step ST507).
That is, the unregistered road detecting means records the current
position of the vehicle on the registered road as a candidate for
the vehicle departure point. In contrast, when, in step ST506,
determining that it is not possible that the vehicle has departed
from any registered road, the unregistered road detecting means
skips the processing of step ST507.
[0107] The unregistered road detecting means then adds the distance
which the vehicle has traveled after setting up the candidate for
the vehicle departure point (in step ST508). That is, for each of
candidates for the vehicle departure point which are recorded, the
unregistered road detecting means calculates the traveled distance
which the vehicle has traveled after setting up each candidate for
the vehicle departure point on the basis of the positioning data
from the positioning means 41, the traveled distance indicating the
distance which the vehicle has traveled until the position of the
vehicle is identified as being on the registered road after each
candidate for the vehicle departure point is recorded, and adds the
traveled distance. The unregistered road detecting means then
checks to see whether or not the traveled distance which the
vehicle has traveled after setting up each candidate for the
vehicle departure point is longer than a predetermined value L1 (in
step ST509). When, in this step ST509, determining that the
traveled distance which the vehicle has traveled after setting up
each candidate for the vehicle departure point is not longer than
the predetermined value L1, i.e., the traveled distance is equal to
or shorter than the predetermined value L1, the unregistered road
detecting means ends the unregistered road detection
processing.
[0108] In contrast, when, in step ST509, determining that the
traveled distance which the vehicle has traveled after setting up
each candidate for the vehicle departure point is longer than the
predetermined value L1, the unregistered road detecting means
recognizes that the vehicle has not departed from the registered
road at the recorded candidate for the vehicle departure point, and
deletes the recorded candidate for the vehicle departure point and
related information (in step ST510). For example, in the example
shown in FIG. 19, although the unregistered road detecting means
records points C and D as candidates for the vehicle departure
point, the unregistered road detecting means deletes the point C
from the candidates for the vehicle departure point because the
traveled distance which the vehicle has traveled after setting up,
as a candidate for the vehicle departure point, the point C is
larger than the predetermined value L1 before recording the point
D. After that, the unregistered road detecting means ends the
unregistered road detection processing.
(2) Vehicle Departure Determining Processing
[0109] In the vehicle departure determining processing, the
unregistered road detecting means carries out addition of the free
distance and clearing of the matching distance first (in step
ST511). That is, the unregistered road detecting means calculates
and adds the free distance on the basis of the positioning data
from the positioning means 41, and also sets the matching distance
to zero. The unregistered road detecting means then checks to see
whether or not the free distance is longer than a predetermined
value L2 (in step ST512). When, in this step ST512, determining
that the free distance is not longer than the predetermined value
L2, i.e., the free distance is equal to or shorter than the
predetermined value L2, the unregistered road detecting means ends
the unregistered road detection processing.
[0110] In contrast, when, in step ST512, determining that the free
distance is longer than the predetermined value L2, the
unregistered road detecting means finally determines that the
vehicle has departed from the registered road, and sets the
unregistered road detection flag (in step ST513). The unregistered
road detecting means then checks to see whether any candidate for
the vehicle departure point has not been set up yet (in step
ST514). That is, the unregistered road detecting means checks to
see whether it has recorded any candidate for the vehicle departure
point by checking the number of recorded candidates for the vehicle
departure point. When, in this step ST514, determining that one or
more candidates for the vehicle departure point have been already
set up, the unregistered road detecting means ends the unregistered
road detection processing.
[0111] In contrast, when, in step ST514, determining that any
candidate for the vehicle departure point has not been set up yet,
the unregistered road detecting means adds a candidate for the
vehicle departure point (in step ST515). That is, the unregistered
road detecting means searches for the coordinates of a point on the
traveling path which is backwardly located by the free distance
from the current position of the vehicle, and records the
coordinates of the point as a candidate for the vehicle departure
point. For example, in the example shown in FIG. 19, the
unregistered road detecting means finally determines that the
vehicle has departed from the registered road before the F point at
which the free distance is longer than the predetermined value L2.
After that, the unregistered road detecting means ends the
unregistered road detection processing.
(3) Return Judgment Processing
[0112] In the return judgment processing, the unregistered road
detecting means carries out vehicle return judgment first using the
same method as that shown in step ST408 of above-mentioned
embodiment 1 (in step ST516). In this processing, the unregistered
road detecting means determines that the vehicle has returned to a
registered road when the road matching means 42 has continuously
set up candidates for the current position of the vehicle on a
registered road while the vehicle has traveled a predetermined
distance or longer. On the basis of the judgment result in step
ST516, the unregistered road detecting means then checks to see
whether it is possible that the vehicle has returned to a
registered road (in step ST517). When, in this step ST517,
determining that it is possible that the vehicle has returned to a
registered road, the unregistered road detecting means adds a
candidate for the vehicle return point (in step ST518). That is,
the unregistered road detecting means additionally records the
current position of the vehicle on the registered road as a
candidate for the vehicle return point. In contrast, when, in step
ST517, determining that it is not possible that the vehicle has
returned to any registered road yet, the unregistered road
detecting means skips the process of step ST518.
[0113] The unregistered road detecting means then checks to see
whether or not the matching distance is equal to or longer than a
predetermined value L3 (in step ST519). When, in this step ST519,
determining that the matching distance is not equal to or longer
than the predetermined value L3, i.e., the matching distance is
shorter than the predetermined value L3, the unregistered road
detecting means recognizes that the vehicle has not returned to any
registered road yet, and ends the unregistered road detection
processing.
[0114] In contrast, when, in step ST519, determining that the
matching distance is equal to or longer than the predetermined
value L3, the unregistered road detecting means recognizes that the
vehicle has returned to a registered road, and carries out
processes of steps ST520 to ST527. For example, in the example
shown in FIG. 19, the unregistered road detecting means records
points G, M and P as candidates for the vehicle return point, and
finally determines that the vehicle has returned to a registered
road at the point S at which the matching distance becomes longer
than the predetermined value L3.
[0115] In step ST520, the unregistered road detecting means checks
to see whether any candidate for the vehicle return point has not
been set up yet. That is, the unregistered road detecting means
checks to see whether any candidates for the vehicle return point
has not been recorded yet by checking the number of recorded
candidates for the vehicle return point. When, in this step ST520,
determining that any candidate for the vehicle return point has not
been set up yet, the unregistered road detecting means adds a
candidate for the vehicle return point (in step ST521). That is,
the unregistered road detecting means searches for the coordinates
of a point on the traveling path which is backwardly located by the
matching distance from the current position of the vehicle
(particularly, the current position of the vehicle on the
registered road which is stored as a set with the positioning
data), and records the coordinates of the point as a candidate for
the vehicle return point. When, in step ST520, determining that one
or more candidates for the vehicle return point have been set up,
the unregistered road detecting means skips the processing of step
ST521.
[0116] The unregistered road detecting means then selects a
combination of a candidate for the vehicle departure point and a
candidate for the vehicle return point (in step ST522). That is,
for each of all combinations of the candidates for the vehicle
departure point and the candidates for the vehicle return point,
the unregistered road detecting means carries out the same affine
transformation as that explained in above-mentioned embodiment 1 so
that the coordinates of the ends of a traveling path corresponding
to each of all the combinations of the candidates for the vehicle
departure point and the candidates for the vehicle return point
match with those of the corresponding candidates for the vehicle
departure point and for the vehicle return point, respectively, and
calculates an amount of transformation caused by the affine
transformation in the coordinate system, concretely, an amount of
movement in the coordinate system, an expansion-and-contraction
coefficient, and a rotation angle. The unregistered road detecting
means then selects a combination of a candidate for the vehicle
departure point and a candidate for the vehicle return point which
minimizes the amount of transformation in the coordinate system
caused by the affine transformation.
[0117] The unregistered road detecting means then checks to see
whether the amount of transformation in the coordinate system falls
within an allowable range (in step ST523). When, in this step
ST523, determining that the amount of transformation in the
coordinate system falls within the allowable range, the
unregistered road detecting means recognizes that it could specify
an unregistered road section, and carries out calculation of the
coordinates of the unregistered road by means of the same method as
shown in step ST414 of above-mentioned embodiment 1 (in step
ST524). That is, the unregistered road detecting means creates road
data from the traveling path on which it has performed a coordinate
transformation so that the traveling path is connected to the
specified unregistered road section. In contrast, when, in this
step ST523, determining that the amount of transformation in the
coordinate system does not fall within the allowable range, the
unregistered road detecting means recognizes that it could not
specify any unregistered road section, and skips the processing of
step ST524.
[0118] The unregistered road detecting means then initializes the
traveling path in order to place itself in a state in where it can
detect the next unregistered road (in step ST525), clears the
unregistered road detection flag (in step ST516), and further
initializes both the candidates for the vehicle departure point and
the candidates for the vehicle return point (in step ST527). After
that, the unregistered road detecting means ends the unregistered
road detection processing. In the example shown in FIG. 19, the
unregistered road detecting means compares amounts acquired by
performing a coordinate transformation on traveling path portions
respectively corresponding to the D-G section, the D-M section, and
the D-P section with one another, and selects the D-P section as
the unregistered road section.
[0119] As previously explained, the navigation apparatus in
accordance with this embodiment 11 records a point at which it is
possible that the vehicle has departed from a registered road and a
point at which it is possible that the vehicle has returned to a
registered road, as a candidate for the vehicle departure point and
a candidate for the vehicle return point, respectively, and, when
the state of the identification of the current position of the
vehicle continues to be the matching state while the vehicle
travels a predetermined distance or longer along a registered road
after traveling an unregistered road section, selects one of all
combinations of candidates for the vehicle departure point and
candidates for the vehicle return point and performs a coordinate
transformation on a corresponding traveling path within a
predetermined limit, and determines a combination of a candidate
for the vehicle departure point and a candidate for the vehicle
return point which minimizes the amount of transformation as an
unregistered road section. Therefore, this embodiment can improve
the probability of succeeding in the detection of an unregistered
road.
[0120] In accordance with this embodiment 11, in a case in which
traveling path portions corresponding to all the combinations of
candidates for the vehicle departure point and candidates for the
vehicle return point include two or more traveling path portions
each of which minimizes the amount of coordinate transformation
indicated by the amount of movement in the coordinate system,
expansion-and-contraction coefficient, and rotation angle of each
traveling path, which are caused by the coordinate transformation,
within predetermined limits which are estimated from the accuracy
of the coordinates of roads indicated by road data, the accuracy of
the current position of the vehicle, and the accuracy of correction
of each sensor, and each of which is determined to show the highest
consistency with a registered road, the navigation apparatus can
determine, as the vehicle departure point and the vehicle return
point, a candidate for the vehicle departure point and a candidate
for the vehicle return point for which the distance which the
vehicle has traveled while the matching result data has been
indicating the matching state is the longest, respectively. In this
case, the navigation apparatus can select only one combination of a
candidate for the vehicle departure point and a candidate for the
vehicle return point, and can improve the reliability of the
coordinates of the unregistered road section which is created on
the basis of this selected combination of a candidate for the
vehicle departure point and a candidate for the vehicle return
point.
Embodiment 12
[0121] A navigation apparatus in accordance with this embodiment 12
differs from the navigation apparatus in accordance with embodiment
1 in the functions of a road matching means 42 and an unregistered
road detecting means 45. Hereafter, the details of processing
carried out by the road matching means 42 and processing carried
out by the unregistered road detecting means 45 will be explained
with reference to an explanatory diagram shown in FIG. 22.
[0122] When acquiring, as positioning data, the position and
direction of the vehicle from a positioning means 41, the road
matching means 42 judges the state of the identification of the
position of the vehicle (i.e., whether the identification state is
a matching state or a free state) according to the following
conditions, and outputs the result of this judgment as matching
result data. That is, when there exists one or more candidates for
the position of the vehicle having a distance from the current
position of the vehicle which is equal to or shorter than a
predetermined distance and having an angular difference with the
direction of the vehicle which is equal to or smaller than a
predetermined angle, the road matching means 42 determines that the
identification state is the matching state, or determines that the
identification state is the free state otherwise. However, the
navigation apparatus can be so constructed as not to carry out
judgment about the angular difference when the navigation apparatus
can assume that the vehicle is rotating largely and rotationally
by, for example, making a right or left turn, e.g., when the
angular difference between the newest direction of the vehicle and
the immediately-preceding direction of the vehicle is equal to or
larger than a predetermined angle. In this case, when a road link
exists in the vicinity of the position of the vehicle even if the
angular difference is large, the navigation apparatus determines
that the identification state is the matching state. The navigation
apparatus can be so constructed as to take into consideration an
attribute for candidates for the position of the vehicle, such as
one-way traffic, when judging the identification state. In this
case, even if the above-mentioned conditions about the distance and
angle are satisfied, when there exists, as candidates for the
position of the vehicle, only a candidate for the position of the
vehicle having an attribute of NO TRAFFIC, the navigation apparatus
determines that the identification state is the free state.
[0123] When the road matching means 42 determines that the
identification state is the matching state, it sends, as candidate
position data, one or more candidates for the existing position of
the vehicle which satisfy the conditions at the time of determining
that the identification state is the matching state, as well as the
current position and direction of the vehicle which are calculated
by the positioning means 41, to the unregistered road detecting
means 45.
[0124] FIG. 22A is a diagram indicating a relation between the
traveling path of the vehicle (i.e., a series of the detected
current positions of the vehicle), and candidates for the existing
position of the vehicle on a registered road, and FIG. 22B shows a
relation among traveling path data which is a set of positioning
data at times, matching result data, candidate position data, and
connection relation data which will be mentioned below.
[0125] The unregistered road detecting means 45 refers to the
positioning data from the positioning means 41, and the matching
result data from the road matching means 42, and the candidate
position data, and sets up each of a detection start point and a
detection end point for an unregistered road on a registered road
according to the distance between each current position of the
vehicle indicated by the positioning data and the corresponding
candidate for the existing position of the vehicle on a registered
road. In this case, for example, the unregistered road detecting
means 45 can select, as the detection start point or detection end
point, a candidate for the existing position of the vehicle on a
registered road which is the nearest to the series of the detected
current positions of the vehicle indicated by the positioning
data.
[0126] According to this structure, the precision of setting up the
detection start point and the detection end point can be improved.
Because it is not necessary to refer to the road data stored in the
road-map-data storage means 43 anew in order to set up the
detection start point and the detection end point, the amount of
arithmetic operations and the amount of memory consumption can be
reduced.
[0127] Furthermore, the road matching means 42 can be so
constructed as to send the attributes of a road on which each
candidate for the existing position of the vehicle exist, as well
as the candidate position data indicating the candidates for the
existing position of the vehicle, to the unregistered road
detecting means 45. In this case, the unregistered road detecting
means 45 refers to the matching result data, the candidate position
data, and the attributes from the road matching means 42, and, when
setting up each of the detection start point and the detection end
point for an unregistered road on a registered road, selects, as
the detection start point or detection end point, a candidate for
the existing position of the vehicle on the registered road in
consideration of the attributes. For example, the unregistered road
detecting means provides an attribute which makes it easy to make a
connection with an unregistered road in advance, and gives a higher
priority to a candidate with the attribute for the existing
position of the vehicle on a registered road than to any other
candidates with another attribute for the existing position of the
vehicle on a registered road when setting up the detection start
point and the detection end point. As a result, the precision of
setting up the detection start point and the detection end point
can be improved.
[0128] Furthermore, the road matching means 42 can be so
constructed as to judge whether a candidate for the existing
position of the vehicle at the current time is connected to a
candidate for the existing position of the vehicle corresponding to
the position of the vehicle at a time immediately before or before
the candidate for the existing position of the vehicle at the
current time is determined, and to send, as connection relation
data, the judgment result to the unregistered road detecting means
45. In this judgment of whether the candidate for the existing
position of the vehicle at the current time is connected to the
candidate for the existing position of the vehicle corresponding to
the position of the vehicle at a time immediately before or before
the candidate for the existing position of the vehicle at the
current time is determined, the road matching means judges not only
whether they are connected to each other as a road network, but
whether they are connected to each other within the limit of a
predetermined distance so that they are not contradictory to the
traveling path data.
[0129] In this case, the unregistered road detecting means 45
refers to the matching result data from the road matching means 42,
the candidate position data, and the connection relation data, and,
when setting up each of the detection start point and the detection
end point for the unregistered road on a registered road,
determines, for example, the distance along the candidates for the
existing position of the vehicle on a registered road, and sets up
each of the detection start point and the detection end point for
the unregistered road on a registered road along which the
connection with the unregistered road continues over a
predetermined distance or longer. As a result, the precision of
setting up a connection point between the registered road and the
unregistered road can be improved.
[0130] FIG. 23 is a block diagram showing the structure of a
navigation apparatus in accordance with a variant of this
embodiment 12. This navigation apparatus additionally includes an
input means 101 in addition to the components of the navigation
apparatus in accordance with embodiment 1, and an unregistered road
editing means 100 is added to the signal processing unit 4.
[0131] The input means 101 is used in order for the user to input
coordinates. The coordinates inputted from this input means 101 are
sent to the unregistered road editing means 100. The unregistered
road editing means 100 creates the coordinates of an unregistered
road which connects the coordinates inputted from the input means
101 with each other. The coordinates of the unregistered road
created by this unregistered road editing means 100 are sent to the
road data generating means 46, the road-map-data storage means 43,
and the display control means 44.
[0132] In the navigation apparatus in accordance with this variant
of embodiment 12, the unregistered road editing means 100 presents
the user with the traveling path data sent thereto from the
unregistered road detecting means 45 via the display control means
44 and the display means 5, and creates the coordinates of the
unregistered road which connects the coordinates which are inputted
by the user using the input means 101 with each other. On the basis
of these created coordinates, the unregistered road editing means
creates the traveling path of the unregistered road, and presents
the user with the traveling path. As a result, the user can input
correct coordinates by referring to the relation between the
displayed traveling path and registered roads. Furthermore, because
the user is enabled to correctly input the coordinates of a
connection point between a registered road and the unregistered
road, or the coordinates of a passing point on the unregistered
road, the accuracy of the coordinates of the unregistered road can
be improved.
[0133] Furthermore, in the navigation apparatus in accordance with
this variant of embodiment 12, the unregistered road editing means
100 can be so constructed as to present the user with associated
candidate position data in addition to the traveling path data sent
thereto from the unregistered road detecting means 45 via the
display control means 44 and the display means 5, and to create the
coordinates of the unregistered road which connect coordinates
which the user inputs using the input means 101 by selecting one
data from candidate position data. In this case, the user can input
correct coordinates by selecting a candidate position from
candidate positions on a registered road which is presented for the
user. Furthermore, because the user is enabled to correctly input
the coordinates of a connection point between a registered road and
the unregistered road, or the coordinates of a passing point on the
unregistered road, the accuracy of the coordinates of the
unregistered road can be improved.
[0134] Many widely different embodiments of the present invention
may be constructed without departing from the spirit and scope of
the present invention. It should be understood that the present
invention is not limited to the specific embodiments described in
the specification, except as defined in the appended claims.
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