U.S. patent application number 09/107530 was filed with the patent office on 2001-08-16 for navigation system for providing an optimal route from traffic messages.
This patent application is currently assigned to MANNESMANN VDO A.G.. Invention is credited to EMMERINK, CARLA J.M., LAHAIJE, PAUL D.M., MULDER, EDWIN W., WALGERS, ERIK J..
Application Number | 20010014848 09/107530 |
Document ID | / |
Family ID | 8228504 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010014848 |
Kind Code |
A1 |
WALGERS, ERIK J. ; et
al. |
August 16, 2001 |
NAVIGATION SYSTEM FOR PROVIDING AN OPTIMAL ROUTE FROM TRAFFIC
MESSAGES
Abstract
A vehicle navigation system (100) comprises a planning module
(110) for planning a route between an origin and a destination and
subsequently guides the driver along the planned route. The system
further comprises a receiver (124) for the reception of traffic
messages related to problem locations on roads, which messages are
transferred to the driver. The navigation system according to the
invention is arranged to read from its storage medium (106) with
the map database additional information (404) indicating the
potential problem locations for roads in the database. In this way,
the information from the traffic message can be combined with the
information from the map database and further exploited in the
system, e.g. for planning a new route.
Inventors: |
WALGERS, ERIK J.;
(EINDHOVEN, NL) ; EMMERINK, CARLA J.M.;
(EINDHOVEN, NL) ; LAHAIJE, PAUL D.M.; (EINDHOVEN,
NL) ; MULDER, EDWIN W.; (EINDHOVEN, NL) |
Correspondence
Address: |
DAVID M. THIMMIG
MAYER, BROWN & PLATT
P.O. BOX 2828
CHICAGO
IL
60690-2828
US
|
Assignee: |
MANNESMANN VDO A.G.
|
Family ID: |
8228504 |
Appl. No.: |
09/107530 |
Filed: |
June 30, 1998 |
Current U.S.
Class: |
701/410 ;
455/457 |
Current CPC
Class: |
G08G 1/096872 20130101;
G01C 21/3461 20130101; G08G 1/096827 20130101; G08G 1/096844
20130101 |
Class at
Publication: |
701/209 ;
701/210; 455/457 |
International
Class: |
G01C 021/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 1997 |
EP |
97202003.6 |
Claims
1. A navigation system for guiding a driver in a vehicle, the
system comprising: read means for reading chain information from a
storage medium comprising a first storage unit with chains and
nodes, a chain representing a road element and being connected to
another chain via a node, process means for exploiting said chain
information, for example a planning module for planning a route or
a display module for displaying a map on a display, and a receiver
for the reception of a traffic message related to a pre-defined
problem location, characterised in that the read means are arranged
to read from the storage medium for a particular chain related to a
particular node corresponding to a problem location additional
chain information comprising an identification of that problem
location.
2. A navigation system as claimed in claim 1, the system comprising
a planning module for planning a route between an origin and a
destination, wherein the planning module is arranged to take into
account the particular chains that fall within a predetermined
search area, the system being arranged to create a list containing
the identifications of the problem locations related to the
particular chains in the search area, insofar present.
3. A navigation system as claimed in claim 2, the system being
arranged to create a sub-list containing the identifications of the
problem locations related to the particular chains on the planned
route, insofar present.
4. A navigation system as claimed in claim 1, wherein the read
means are arranged to read the additional chain information from a
second storage unit of the storage medium.
5. A navigation system for guiding a driver in a vehicle, the
system comprising: read means for reading chain information from a
storage medium comprising a first storage unit with chains and
nodes, a chain representing a road element and being connected to
another chain via a node, process means for exploiting said chain
information, for example a planning module for planning a route or
a display module for displaying a map on a display, and a receiver
for the reception of a traffic message related to a pre-defined
problem location, characterised in that the read means are arranged
to read from the storage medium for the problem location related to
the traffic message a first identification of a first one of the
chains connected to a particular to the problem location
corresponding node.
6. A navigation system as claimed in claim 4, wherein the read
means are arranged to read from the storage medium for the problem
location related to the traffic message a second identification of
a second one of the chains connected to a particular to the problem
location corresponding node, the second one extending in a
direction opposite to the first one.
7. A storage medium for use in a navigation system, the storage
medium comprising a first storage unit with chains and nodes, a
chain representing a road element and being connected to another
chain via a node, characterised in that the storage medium
comprises for a particular chain a first identification of a first
problem location, which first problem location corresponds to a
particular node related to the particular chain.
8. A storage medium as claimed in claim 7, comprising for the
particular chain a second identification of a second problem
location, which second problem location corresponds to a particular
node related to the particular chain and pertains to the opposite
direction of travel compared with the first problem location.
9. A storage medium as claimed in claim 7, the storage medium
comprising a second storage unit comprising the first
identification.
10. A storage medium for use in a navigation system, the storage
medium comprising a first storage unit with chains and nodes, a
chain representing a road element and being connected to another
chain via a node, characterised in that the storage medium
comprises for a particular pre-defined problem location a first
identification of a first one of the chains, which chain is
connected to a with the pre-defined problem location corresponding
node.
11. A storage medium as claimed in claim 10, comprising for the
particular problem location a second identification of a second one
of the chains, which second one of the chains is connected to the
with the problem location corresponding node and which second one
of the chains pertains to a direction of travel opposite to the
first one.
Description
[0001] The invention relates to a navigation system for guiding a
driver in a vehicle, the system comprising:
[0002] read means for reading chain information from a storage
medium comprising a first storage unit with chains and nodes, a
chain representing a road element and being connected to another
chain via a node,
[0003] process means for exploiting said chain information, for
example a planning module for planning a route or a display module
for displaying a map on a display, and
[0004] a receiver for the reception of a traffic message related to
a pre-defined problem location.
[0005] The invention further relates to a storage medium for use in
a navigation system, the storage medium comprising a first storage
unit with chains and nodes, a chain representing a road element and
being connected to another chain via a node.
[0006] Such a system is described in the article "Traffic
messaging, dynamic updating and road database standards: the major
issues", S. Quere and T. Wood, IEE Colloquium on `Prometheus and
Drive` (Digest No. 172), pp. 9/1-3, Oct. 15, 1992. This computer
assisted driver information system comprises a digital map
representing the roads and junctions on which the driver can
travel. The digital map resides on some storage medium that can be
read by the navigation system. Based on the information in the map,
the navigation system guides the driver during his journey. The
digital map on the storage medium is static in that it reflects the
information of roads at the moment the data for the storage medium
is released. Later changes to the roads after the storage medium
has been manufactured are not present. The known system includes a
receiver for the reception of traffic messages that are broadcast
according to the Radio Data System (RDS). In RDS, the message is
broadcast together with the audio signals of a radio program and
the RDS receiver in the vehicle can receive the combined signals
and separate the message from the audio. Within RDS, the Traffic
Message Channel (TMC) is a set of coded traffic messages, agreed by
the European Conference of Ministers of Transport (ECMT) and laid
down in the pre-standard prENV/278/4/1/0010. The traffic message
according to TMC provides, among others, an event and a location.
An event relates to a happening or circumstance of importance to a
driver, like a temporary road closure, slow traffic on a road or
fog. A large number of events have been standardised and the
message contains a code indicating such standardised event. The
location in the traffic message indicates the area, highway segment
or point location where the source of the problem is situated. In a
country, the respective authority has defined a number of potential
problem locations in advance and has given these locations a unique
number. The traffic message contains such problem location number
to identify the problem location at hand.
[0007] After the receiver has received the traffic message, the
system consults on the basis of the code and problem location
number a local table to establish the event and the problem
location of the traffic message. Subsequently the driver is
informed through a spoken message and/or a written message. The
traffic messages are typically intended directly for the driver and
have been coded in isolation from the digital map of the navigation
system. Therefore, the messages cannot be processed by the
navigation system and cannot be used to update the static digital
map on the storage medium, but are only supplied to the driver.
[0008] It is an object of the invention to provide a navigation
system of the kind set forth which is able to exploit traffic
messages related to problem locations in combination with the road
information on the storage medium in an efficient way. This object
is achieved according to the invention in a navigation system which
is characterised in that the read means are arranged to read from
the storage medium for a particular chain related to a particular
node corresponding to a problem location additional chain
information comprising an identification of that problem location.
Using the additional chain information the system can easily
establish to which problem location a chain of which the system
exploits the information relates. If a traffic message is received,
the system can then compare the problem location to which the
message relates with the problem location to which the chain
relates. If these are different problem locations, the system may
discard the message else the system may further interpret the
message in order to determine its consequences.
[0009] An embodiment of the navigation system according to the
invention is characterised in claim 2. When a traffic message is
received, the system determines whether the identification of the
problem location to which the traffic message relates is present in
the list related to chains that are in the search area and thus
have been considered when the route was planned. If the
identification is not present, then the system may discard the
traffic message since it relates to a problem location that has no
effect on the planned route. If the identification is present, then
this means that the traffic message is related to a problem
location in the search area and the system may decide to plan a new
route. Thanks to the list, the system can quickly determine whether
a traffic message is relevant for the planned route without having
to access all the chains of the search area.
[0010] An embodiment of the navigation system according to the
invention is characterised in claim 3. When a traffic message is
received, the system can through accessing the sub-list quickly
determine whether the problem location of the traffic message is
related to a problem location on the planned route. If this is the
case, the system may decide to re-plan the route between the
current vehicle position and the destination, taking into account
the newly received information in the traffic message.
[0011] An embodiment of the navigation system according to the
invention is characterised in claim 4. This allows the storage of
the additional chain information on a separate place on the storage
medium, independent from the first storage unit. This has the
advantage that a version of a storage medium including the second
storage unit is compatible with an earlier version of a storage
medium with only the first storage unit, i.e. a system designed for
reading the earlier version need not be adapted in order to be able
to read the later version and vice versa.
[0012] The object of the invention is alternatively achieved
according to the invention in a navigation system which is
characterised in that the read means are arranged to read from the
storage medium for the problem location related to the traffic
message a first identification of a first one of the chains
connected to a particular to the problem location corresponding
node. By reading the identification of the chain connected to the
problem location, the system is able to directly determine the
relevant chain related to a received traffic message. When a
traffic message is received, the system can directly act on the
relevant chain or chains without accessing other chains to see if
they are related to the message. An application is where the system
has displayed a map of roads and subsequently receives a traffic
message concerning a traffic queue at a certain problem location,
whereby the road on which the traffic queue is present must be
highlighted. Through the first identification, the system can
directly locate the chain connected to the certain problem location
and highlight it. Subsequently, the system can determine, based on
the knowledge of the connection of chains and the specification
given in the message, which further chains are affected and must be
highlighted.
[0013] An embodiment of the navigation system according to the
invention is characterised in claim 6. The pre-defined problem
locations are specified in a certain order with respect to each
other, whereby the order corresponds to a certain direction of
travelling. So a problem location has a previous problem location
and a next problem location. A category of traffic messages can
relate to an event in one of two different directions with respect
to the problem location. An example is a traffic message related to
a traffic queue at a specific problem location: the traffic queue
may extent from that specific problem location in the direction of
the previous problem location or from that specific problem
location in the direction of the next problem location. Therefore,
it is advantageous to specify for a problem location a chain in
each direction of travelling so that for both directions the
relevant chain can be directly identified.
[0014] It is a further object of the invention to provide a storage
medium of the kind set forth which enables the exploitation of
traffic messages related to problem locations in combination with
the road information on the storage medium in an efficient way.
This object is achieved according to the invention in a storage
medium which is characterised in that the storage medium comprises
for a particular chain a first identification of a first problem
location, which first problem location corresponds to a particular
node related to the particular chain. A system accessing the
storage medium can establish the identification of the problem
location corresponding to the node of a given chain or chains of
which information has been used. When a traffic message is received
concerning a specific problem location, the system can easily
determine whether this specific problem location relates to the
chain or chains used. The first identification provides an
efficient mechanism to integrate the information on chains and
nodes with the information received through traffic messages.
[0015] An embodiment of the navigation system according to the
invention is characterised in claim 9. By storing the
identification of the problem location in a second storage unit,
separate from the first storage unit, the first storage unit is not
influenced by this storing. This has the advantage that the storage
medium with the stored identifications of problem locations is
compatible with the storage medium without the identifications. In
this way, a system designed for reading the version of the storage
medium without the identifications need not be modified in order to
be able to read the later version of the storage medium with the
identifications of problem locations. Also a later version of the
system can easily be designed in such a way that it can read both
versions of the storage medium.
[0016] The further object of the invention is alternatively
achieved according to the invention in a storage medium which is
characterised in that the storage medium comprises for a particular
pre-defined problem location a first identification of a first one
of the chains, which chain is connected to a with the pre-defined
problem location corresponding node. When a traffic message is
received, the system accessing the storage medium can efficiently
establish which of the chains is connected to the node which
corresponds to the problem location in the traffic message. This
chain can then be processed in accordance with the traffic message.
For example, a system displaying a map can, after a traffic message
has been received concerning a traffic queue at a problem location,
indicate this on the displayed map starting at the respective
chain.
[0017] Further advantageous embodiments of the invention are
recited in dependent Claims.
[0018] The invention and its attendant advantages will be further
elucidated with the aid of exemplary embodiments and the
accompanying schematic drawings, whereby:
[0019] FIG. 1 schematically shows some of the elements of a system
according to the invention,
[0020] FIG. 2 shows an example of problem locations and
interconnecting chains,
[0021] FIG. 3 shows an example of identifications of chains for
given problem locations,
[0022] FIG. 4 shows an example of additional chain information for
2-directional chains,
[0023] FIG. 5 shows an example of additional chain information for
1-directional chains, and
[0024] FIG. 6 shows the organisation of the information on the
storage medium.
[0025] Corresponding features in the various Figures are denoted by
the same reference symbols.
[0026] FIG. 1 schematically shows some of the elements of a system
according to the invention. The system 100 comprises a central unit
102 which controls the operation of the system and which includes
various modules for performing specific tasks. The central unit can
be implemented on a computer comprising a central processor and
working memory loaded with software programs for carrying out the
specific tasks. The system 100 has read means 104 to read
information from a map database stored on a data carrier, like
CD-ROM 106. Other types of carrier can also be used, e.g. magnetic
disk and IC Card. The map database comprises information on roads
of the area to which the particular map relates, e.g. the roads of
a country or of a state. In the map database, a chain is used to
represent a road element identifying an elementary part of a road.
Chains are used to represent the road in a discrete way. Examples
of road elements are: a part of the road between two junctions, a
part of the road with a certain direction, a part of the road with
a certain name, and a part of the road at an intersection.
Furthermore, the map database has nodes, representing the begin and
end points of a road element. So a chain terminates at a node and a
next chain starts at that node, thus forming a network of routes. A
node may be a junction between roads, so more than two chains are
connected to that node, or may be an intermediate point where two
chains are connected. The system 100 is equipped with an interface
108 suitable for receiving information concerning the current
position of the vehicle in which the system is employed. This
information can be supplied by a position determining system like a
GPS receiver, using information broadcast by dedicated satellites.
However, the position information can also be determined in another
way, for instance using a locating system with one or more distance
sensors, for measuring the distance travelled by the vehicle, and a
compass, for measuring the heading of the vehicle. The system 100
further comprises a planning module 110 that is suitable to plan a
route between an origin, e.g. the current position of the vehicle,
and a desired destination. The desired destination is entered into
the system in a convenient way, e.g. by entering the post code via
a keyboard, by entering road names, by entering coordinates or by
pointing to a position on a map displayed by the system. The
planning module 110 searches through the map database for a route
that is optimal according to some criterion. The planning module
creates a large number of possible routes, each comprising a number
of road elements, between the origin and the desired destination.
The criterion can be the travel time, the travel distance, a
combination of time and distance, or some other criterion that can
be derived from information in the map database. The resulting
route, comprising a number of selected chains, is stored in memory
space 112 and the driver of the vehicle is given guidance to follow
this route. To this end, the system comprises a guidance module 114
and an interface 116 for sending the guidance information to
display 118 and/or loudspeaker 120. Providing a driver with
guidance to follow a predetermined route is known in the art and is
for instance described in U.S. Pat. No. 5,537,323 (PHN 13872). The
system 100 may further comprise a display module 122 to display the
chains of a section of the map on display 118. This section is
displayed in a suitable scale and may indicate the planned route,
the current position of the vehicle and the destination.
[0027] The system 100 comprises a receiver 124 for the reception of
traffic messages. The traffic message is interpreted by the system
and information from the message, like the event and the problem
location, may be stored in list 126. The planning module 110 may be
arranged to search only a limited selection of the chains in the
database when planning a route between the origin and the
destination. A limitation of the number of chains to be taken into
account results in a considerable saving of computational effort
and time required to plan a route. The justification for the
limitation is that roads far away from the origin and destination
will probably never be part of the optimal route and can therefore
be safely discarded by the planning module. The planning module
then only searches for chains in the so-called search area, which
is an area including the origin and the destination and which is
formed on the basis of heuristic rules. As will be further
explained below, the storage medium 106 may include an
identification of a problem location to which a chain relates. Now,
the system is arranged to create a list 128 for these
identifications relating to the chains in the search area.
Furthermore the system may be arranged to create a sub-list 130 of
the identifications that relate to chains that are part of the
planned route. When a traffic message is received relating to a
particular problem location, the system can consult the list 128 to
verify whether this particular problem location relates to a chain
that is within the search area, i.e. has been considered by the
planning module while creating the planned route. If the chain
relating to the particular problem location is outside the search
area, the message relates to an event that is not relevant for the
planned route and may safely be discarded. If the chain relating to
the particular problem location is inside the search area, the
system must interpret the message and it may be necessary to
re-plan a route to the destination now taking into account the
circumstances indicated in the traffic message. The following
situations can occur:
[0028] the chain of the problem location is in the search area, but
not on the planned route, and the event indicates a worse travel
condition for that chain: re-planning is not necessary since the
planned route will remain the optimal one;
[0029] the chain of the problem location is in the search area, but
not on the planned route, and the event indicates an improved
travel condition for that chain: re-planning is necessary since a
route including the chain could have become better than the planned
route;
[0030] the chain of the problem location is in the search area and
on the planned route, and the event indicates a worse travel
condition for that chain: re-planning is necessary since the
planned route could no longer be the optimal one;
[0031] the chain of the problem location is in the search area and
on the planned route, and the event indicates an improved travel
condition for that chain: re-planning is not necessary since the
planned route has improved and will remain the optimal on.
[0032] FIG. 2 shows an example of problem locations and
interconnecting chains. An authority of a state or a country
determines which locations on the roads for which it is responsible
qualify as locations for which it must be possible to broadcast an
event in a traffic message. These locations are called problem
locations and are given a unique problem location number to
identify them in the traffic message. Furthermore, the problem
locations are ordered with respect to a pre-defined direction of
travelling, by specifying for a problem location a previous problem
location and a next problem location. The example shows a problem
location 202, with problem location number 75, a problem location
204, with problem location number 80, and a problem location 206,
with problem location number 15. Roads are represented in the
database of the system by a series of chains, each having an
identification, e.g. chain 208 has identification c2. In the
example of FIG. 2, the roads between the problem locations have
different lanes for the different directions of travelling and this
is represented by a different series of chains for each direction.
For instance the series c1-c2-c3 is used to travel from problem
location 202 to problem location 204 and the series c7-c8-c9 is
used to travel from problem location 204 to problem location 202. A
problem location may indicate a certain relatively small region
instead of a single point position. For instance a junction of
highways may be in the form of a clover leaf with various exits and
fly-overs and still be identified as a single problem location.
Then the chains of such a junction are considered as part of the
problem location and not as road elements between problem
locations. For instance, chains c20, c21 and c22 are within the
region 210 of problem location 204 and are considered internal
chains of that problem location. The database of the system
contains information about a chain, like its start and end node,
its direction, its name and many more items. This information is
exploited by the system in various ways, e.g. for route planning
and for drawing a map on the display. Now, according to the
invention the storage medium contains additional information for a
chain indicating to what problem location this chain leads. In the
example of FIG. 2, chain 208 leads to problem location 204 and this
is represented by the additional chain information 212. Through
this additional chain information, the information present in the
database, which information is related to the chains, can be linked
to the information received in the traffic messages, which
information is related to problem location numbers.
[0033] FIG. 3 shows an example of identifications of chains for
given problem locations. The storage medium comprises information
on the pre-defined problem locations. This can be in the form of a
table 302, wherein a column represents a certain type of
information about the problem location and a row corresponds to a
record with the various fields of information for a given problem
location. The example shows the following type of information:
[0034] column 304, the problem location number,
[0035] column 306, the problem location number of the previous
problem location,
[0036] column 308, the problem location number of the next problem
location,
[0037] column 310, the identification of the connected chain,
extending from the problem location into the positive direction,
and
[0038] column 312, the identification of the connected chain,
extending from the problem location into the negative
direction.
[0039] Many more type of information can be stored for a problem
location, but are not of relevance for the present invention. The
rows for which data is shown in the fields correspond to the
problem locations of FIG. 2: row 314 corresponds to problem
location 206, row 316 to problem location 202, and row 318 to
problem location 204. The identification of the chains, available
in the database of the system, for given problem location numbers,
available from received traffic messages, provide a means for
combining the information from the database with the information
from the traffic messages. This information is stored on the
storage medium but outside the database with the chains, so as to
leave the structure of the database unchanged. When a traffic
message with a given problem location is received, the system is
able to directly determine which chains are connected to that
problem location and may be affected by the event of the traffic
message.
[0040] FIG. 4 shows an example of additional chain information for
2-directional chains. A chain in the database has a node A and a
node B, wherein by definition the x-co-ordinate of the node A is
the smallest of the two nodes. An example is chain 402 with node
401 as its node A and with node 403 as its node B. In this
embodiment of the invention, the additional chain information
comprises three items: the number of the problem location to which
the chain leads, an indication whether the direction to reach that
problem location is positive or negative, and the node in the
direction of the referred problem location. For example chain 402,
has additional chain information 404 comprising `20+B`. This means
that chain 402 leads towards problem location number 20, which is
in the direction defined as positive and that this is in the
direction of the node B of the chain. Since chain 402 can be
travelled in two directions, there is another additional
information item 406 for this chain comprising `10-A`. This means
that chain 402 leads, if travelled in the reverse direction, to
problem location 10, in the negative direction towards node A of
the chain.
[0041] FIG. 5 shows an example of additional chain information for
1-directional chains. Now there are different chains for the
different directions of travelling, e.g. the different lanes on a
highway, and each chain has one additional information item, e.g.
item 502 of chain 504.
[0042] FIG. 6 shows the organisation of the information ?c1 the
storage medium. The storage medium 600 has a first storage unit 602
comprising the information of the chains and nodes. In a preferred
embodiment, the first storage unit 602 is divided into blocks each
corresponding to a rectangular area of the map. A block in that
embodiment has a maximum size of 16 Kbytes and the size of the
covered rectangular area depends on the amount of road information
in that area. The storage medium has a second storage unit 604
comprising the additional chain information. If a chain has such
additional chain information there is an entry for that chain in
the second storage unit. The additional chain information includes
the identification of a problem location to which the chain leads.
For example chain 402, with identification c100, has additional
chain information 404 including the first identification 606 of the
related problem location. For a 2-directional chain like chain 402,
there is a second additional information item 406 including a
second identification 608 of the problem location to which the
chain leads when travelled in the other direction. By storing the
identifications of the problem locations in the second storage unit
604, the structure of the first storage unit 602 remains unchanged,
despite the addition of the identifications. An advantage is that
the basic map information remains the same and that no new division
into rectangular areas is required, which could be necessary if the
identifications of the problem location would be stored directly
with the chains in the first storage unit. A further advantage is
that a later version of the storage medium including the
identifications of problem locations is compatible with the
previous version of the storage medium without the identifications,
as far as the first storage unit with the chains and nodes is
concerned. This means that a previous version of the navigation
system, i.e. a version which is not designed to read the
identification of the problem location, is still able to read the
later version of the storage medium.
[0043] The storage medium may further comprise a storage unit like
table 302, that provides the identification of the chains connected
to given problem location. For the problem location 204, with
problem location number 80, there is stored a first identification
610 which identifies the chain connected to the problem location
and leading away from it in the positive direction. Also for the
problem location 204 a second identification 612 is stored, this
one identifying a chain connected to the problem location and
leading away from it in the negative direction. This storage unit
is also separate from the first storage unit, so as to not change
the structure of the first storage unit.
[0044] The second storage unit 604 and the table 302 both provide a
mechanism for integrating the information received in a traffic
message with the information available in the database of the
navigation system. These mechanisms function independently from
each other and one may be present on the storage medium without
requiring the presence of the other.
* * * * *