U.S. patent application number 11/404600 was filed with the patent office on 2007-02-15 for apparatus and method for switching navigation mode between vehicle navigation mode and personal navigation mode in navigation device.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Hyun-Su Hong, Jae-Myeon Lee, Sung-Chul Yang.
Application Number | 20070038364 11/404600 |
Document ID | / |
Family ID | 36809066 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070038364 |
Kind Code |
A1 |
Lee; Jae-Myeon ; et
al. |
February 15, 2007 |
Apparatus and method for switching navigation mode between vehicle
navigation mode and personal navigation mode in navigation
device
Abstract
Provided is an apparatus and method for switching a navigation
mode between a vehicle navigation mode and a personal navigation
mode in a navigation device supporting vehicle navigation and
personal navigation. Switching between the vehicle navigation mode
and the personal navigation mode is performed according to whether
the navigation device is mounted in a navigation device holder,
whether a GPS speed provided by a GPS receiver is higher than a
predetermined speed, and whether a step is detected using an output
of an accelerometer. Since mode switching between the vehicle
navigation mode and the personal navigation mode is automatically
performed, a user does not need to manually perform mode
switching.
Inventors: |
Lee; Jae-Myeon; (Suwon-si,
KR) ; Hong; Hyun-Su; (Seongnam-si, KR) ; Yang;
Sung-Chul; (Suwon-si, KR) |
Correspondence
Address: |
DILWORTH & BARRESE, LLP
333 EARLE OVINGTON BLVD.
UNIONDALE
NY
11553
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
36809066 |
Appl. No.: |
11/404600 |
Filed: |
April 14, 2006 |
Current U.S.
Class: |
701/532 ;
340/995.16 |
Current CPC
Class: |
G01P 15/00 20130101;
G01S 19/52 20130101; G01S 19/42 20130101; G01C 21/00 20130101; G01C
21/26 20130101; G01C 21/3688 20130101; G01C 21/3423 20130101; G01C
21/165 20130101; G01C 21/20 20130101 |
Class at
Publication: |
701/200 ;
701/211; 340/995.16; 701/213 |
International
Class: |
G01C 21/00 20060101
G01C021/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 2005 |
KR |
2005-42075 |
Claims
1. An apparatus for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the apparatus comprising: a personal navigation algorithm
for implementing a personal navigation mode; a vehicle navigation
algorithm for implementing a vehicle navigation mode; an external
device interface for connecting the navigation device and an
external device; and a navigation algorithm controller for
switching the navigation mode between the vehicle navigation mode
and the personal navigation mode according to whether the
navigation device is mounted in a navigation device holder through
the external device interface.
2. The apparatus of claim 1, wherein the navigation algorithm
controller determines whether the navigation device is mounted in
the navigation device holder by checking if a button of the
navigation device for sensing mounting of the navigation device is
depressed.
3. The apparatus of claim 1, wherein the navigation algorithm
controller determines whether the navigation device is mounted in
the navigation device holder by checking if a message indicating
mounting of the navigation device is received from the navigation
device holder.
4. The apparatus of claim 1, wherein the vehicle is a car.
5. An apparatus for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the apparatus comprising: a personal navigation algorithm
for implementing a personal navigation mode; a vehicle navigation
algorithm for implementing a vehicle navigation mode; a speed
measuring unit for providing a speed of the navigation device; and
a navigation algorithm controller for switching the navigation mode
between the vehicle navigation mode and the personal navigation
mode according to whether the speed of the navigation device is
greater than a predetermined speed threshold.
6. The apparatus of claim 5, wherein the speed measuring unit is a
Global Positioning System (GPS) receiver for receiving a GPS signal
and providing a GPS speed.
7. The apparatus of claim 5, wherein the predetermined speed
threshold is statistically determined according to experimental
results.
8. The apparatus of claim 7, wherein if the navigation device is on
a road way, the predetermined speed threshold is set less than a
statistical value.
9. The apparatus of claim 5, wherein the vehicle is a car.
10. An apparatus for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the apparatus comprising: a personal navigation algorithm
for implementing a personal navigation mode; a vehicle navigation
algorithm for implementing a vehicle navigation mode; a step
detecting unit for detecting a step according to movement of the
navigation device; and a navigation algorithm controller for
switching the navigation mode between the vehicle navigation mode
and the personal navigation mode according to whether a step is
detected by the step detecting unit.
11. The apparatus of claim 10, wherein the step detecting unit
comprises an accelerometer for measuring an acceleration according
to movement of the navigation device and outputting the measured
acceleration and detects a step using the measured
acceleration.
12. The apparatus of claim 10, wherein the step detecting unit
detects a step using a zero-crossing method.
13. The apparatus of claim 10, wherein if a step is detected, the
navigation algorithm controller determines whether the number of
detected steps is greater than a predetermined step detected number
and switches the navigation mode to the personal navigation mode if
the number of detected steps is greater than the predetermined step
detected number threshold.
14. The apparatus of claim 13, wherein the predetermined step
detected number threshold is statistically determined according to
experimental results.
15. The apparatus of claim 14, wherein if the navigation device is
on a road way, the predetermined step detected number threshold is
set greater than a statistical value.
16. The apparatus of claim 10, wherein the vehicle is a car.
17. An apparatus for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the apparatus comprising: a personal navigation algorithm
for implementing a personal navigation mode; a vehicle navigation
algorithm for implementing a vehicle navigation mode; an external
device interface for connecting the navigation device and an
external device; a speed measuring unit for providing a speed of
the navigation device; a step detecting unit for detecting a step
according to movement of the navigation device; and a navigation
algorithm controller for switching the navigation mode between the
vehicle navigation mode and the personal navigation mode according
to whether the navigation device is mounted in a navigation device
holder through the external device interface, whether the speed of
the navigation device is greater than a predetermined speed
threshold, and whether a step is detected by the step detecting
unit.
18. The apparatus of claim 17, wherein the navigation algorithm
controller determines whether the navigation device is mounted in
the navigation device holder by checking if a button of the
navigation device for sensing mounting of the navigation device is
depressed.
19. The apparatus of claim 17, wherein the navigation algorithm
controller determines whether the navigation device is mounted in
the navigation device holder by checking if a message indicating
mounting of the navigation device is received from the navigation
device holder.
20. The apparatus of claim 17, wherein the speed measuring unit is
a Global Positioning System (GPS) receiver for receiving a GPS
signal and providing a GPS speed.
21. The apparatus of claim 17, wherein the predetermined speed
threshold is statistically determined according to experimental
results.
22. The apparatus of claim 21, wherein if the navigation device is
on a road way, the predetermined speed threshold is set less than a
statistical value.
23. The apparatus of claim 17, wherein the step detecting unit
comprises an accelerometer for measuring an acceleration according
to movement of the navigation device and outputting the measured
acceleration and detects a step using the measured
acceleration.
24. The apparatus of claim 17, wherein the step detecting unit
detects a step using a zero-crossing method.
25. The apparatus of claim 17, wherein the vehicle is a car.
26. The apparatus of claim 17, wherein if a step is detected, the
navigation algorithm controller determines whether the number of
detected steps is greater than a predetermined step detected number
and switches the navigation mode to the personal navigation mode if
the number of detected steps is greater than the predetermined step
detected number threshold.
27. The apparatus of claim 26, wherein the predetermined step
detected number threshold is statistically determined according to
experimental results.
28. The apparatus of claim 27, wherein if the navigation device is
on a road way, the predetermined step detected number threshold is
set greater than a statistical value.
29. A method for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the method comprising the steps of: executing a navigation
program upon request from a user and determining whether the
navigation device is mounted in a navigation device holder; and
switching the navigation mode to the vehicle navigation mode if the
navigation device is mounted in the navigation device holder and
switching the navigation mode to the personal navigation mode if
the navigation device is not mounted in the navigation device
holder.
30. The method of claim 29, wherein the step of determining whether
the navigation device is mounted in the navigation device holder
comprises checking if a button of the navigation device for sensing
mounting of the navigation device is depressed; and determining
that the navigation device is mounted in the navigation device
holder if the button is pressed and determining that the navigation
device is not mounted in the navigation device holder if the button
is not depressed.
31. The method of claim 29, wherein the step of determining whether
the navigation device is mounted in the navigation device holder
comprises checking if a message indicating mounting of the
navigation device is received from the navigation device holder;
and determining that the navigation device is mounted in the
navigation device holder if the message is received and determining
that the navigation device is not mounted in the navigation device
holder if the message is not received.
32. The method of claim 29, wherein the vehicle is a car.
33. A method for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the method comprising the steps of: executing a navigation
program upon request from a user and acquiring a speed of the
navigation device; switching the navigation mode to the vehicle
navigation mode if the speed of the navigation device is greater
than a predetermined speed threshold and switching the navigation
mode into the personal navigation mode if the speed of the
navigation device is less than a predetermined speed threshold.
34. The method of claim 33, wherein the predetermined speed
threshold is statistically determined according to experimental
results.
35. The method of claim 34, wherein if the navigation device is on
a road way, the predetermined speed threshold is set less than a
statistical value.
36. The method of claim 33, wherein the vehicle is a car.
37. A method for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the method comprising the steps of: executing a navigation
program upon request from a user and acquiring a measured
acceleration of the navigation device; recognizing a step pattern
using the measured acceleration; determining whether a step is
detected according to the recognition result; and switching the
navigation mode to the vehicle navigation mode if a step is not
detected and switching the navigation mode into the personal
navigation mode if a step is detected.
38. The method of claim 37, wherein a step is detected using a
zero-crossing method.
39. The method of claim 37, further comprising determining whether
the number of detected steps is greater than a predetermined step
detected number if a step is detected; and switching the navigation
mode to the personal navigation mode if the number of detected
steps is greater than the predetermined step detected number
threshold.
40. The method of claim 39, wherein the predetermined step detected
number threshold is statistically determined according to
experimental results.
41. The method of claim 40, wherein if the navigation device is on
a road way, the predetermined step detected number threshold is set
greater than a statistical value.
42. The method of claim 37, wherein the vehicle is a car.
43. A method for switching a navigation mode between a vehicle
navigation mode and a personal navigation mode in a navigation
device, the method comprising the steps of: executing a navigation
program upon request from a user and determining whether the
navigation device is mounted in a navigation device holder;
switching the navigation mode to the vehicle navigation mode if the
navigation device is mounted in the navigation device holder and
acquiring a speed of the navigation device if the navigation device
is not mounted in the navigation device holder; switching the
navigation mode to the vehicle navigation mode if the speed of the
navigation device is greater than a predetermined speed threshold
and acquiring a measured acceleration of the navigation device if
the speed of the navigation device is less than a predetermined
speed threshold; and determining whether a step is detected
according to the recognition result, switching the navigation mode
to the vehicle navigation mode if a step is not detected, and
switching the navigation mode into the personal navigation mode if
a step is detected.
44. The method of claim 43, wherein the step of determining whether
the navigation device is mounted in the navigation device holder
comprises checking if a button of the navigation device for sensing
mounting of the navigation device is pressed; and determining that
the navigation device is mounted in the navigation device holder if
the button is pressed and determining that the navigation device is
not mounted in the navigation device holder if the button is not
depressed.
45. The method of claim 43, wherein the step of determining whether
the navigation device is mounted in the navigation device holder
comprises: checking if a message indicating mounting of the
navigation device is received from the navigation device holder;
and determining that the navigation device is mounted in the
navigation device holder if the message is received and determining
that the navigation device is not mounted in the navigation device
holder if the message is not received.
46. The method of claim 43, wherein the predetermined speed
threshold is statistically determined according to experimental
results.
47. The method of claim 43, wherein if the navigation device is on
a road way, the predetermined speed threshold is set less than a
statistical value.
48. The method of claim 43, further comprising determining whether
the number of detected steps is greater than a predetermined step
detected number if a step is detected; and switching the navigation
mode to the personal navigation mode if the number of detected
steps is greater than the predetermined step detected number
threshold.
49. The method of claim 48, wherein the predetermined step detected
number threshold is statistically determined according to
experimental results.
50. The method of claim 49, wherein if the navigation device is on
a road way, the predetermined step detected number threshold is set
greater than a statistical value.
51. The method of claim 43, wherein a step is detected using a
zero-crossing method.
52. The method of claim 43, wherein the vehicle is a car.
Description
PRIORITY
[0001] This application claims priority under 35 U.S.C. .sctn.119
to an application entitled "Apparatus and Method for Switching
Navigation Mode between Car Navigation Mode and Personal Navigation
Mode in Navigation Device" filed in the Korean Intellectual
Property Office on May 19, 2005 and assigned Serial No. 2005-42075,
the entire contents of which are hereby incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a navigation
system supporting vehicle navigation and personal navigation, and
in particular, to an apparatus and method for switching a
navigation mode between a vehicle navigation mode and a personal
navigation mode in a navigation device supporting vehicle
navigation and personal navigation.
[0004] 2. Description of the Related Art
[0005] Vehicle navigation systems, for example a car navigation
system, recognizes a current position of a user's car. It provides
an optimal route to a user's desired destination to the user, and
guides the user along the optimal route. Generally, car navigation
calculates the current position of the car using a Global
Positioning System (GPS) sensor and a Dead Reckoning (DR) sensor
and guides a route from the current position to the
destination.
[0006] Personal navigation devices guide a route for a walker, and
is similar to car navigation. But unlike car navigation, it
requires more accurate position measurement and more detailed route
guiding because the speed of the walker is generally slower than
that of the car.
[0007] Thus, car navigation and personal navigation perform route
guiding using different navigation algorithms. For example, car
navigation recognizes a current position of a car by directly
integrating outputs of an accelerometer sensor, whereas personal
navigation detects steps of a walker to recognize a current
position of the walker. For this reason, car navigation and
personal navigation use separate dedicated navigation devices for
performing different algorithms or are implemented to operate
different algorithms separately even when using one navigation
device.
[0008] The use of separate navigation devices for car navigation
and personal navigation increases cost and causes inconvenience. To
solve the problem, a navigation device supporting both car
navigation and personal navigation has been recently developed.
[0009] However, in conventional navigation devices supporting car
navigation and personal navigation, a user is required to manually
perform mode switching between car navigation and personal
navigation. In other words, the user manually terminates car
navigation and initiates personal navigation to use personal
navigation during the use of car navigation, and vice versa.
[0010] As a result, conventional navigation devices cause
inconvenience because the user has to separately input car
navigation information and personal navigation information.
Moreover, when the user mistakenly switches to car navigation for
personal navigation or vice versa, it may result in wrong route
guiding.
SUMMARY OF THE INVENTION
[0011] Therefore, it is an object of the present invention to
provide an apparatus and method for switching a navigation mode
between a vehicle navigation mode and a personal navigation mode in
a navigation device supporting vehicle navigation and personal
navigation, in which mode switching is automatically performed
without a user's manipulation.
[0012] It is another object of the present invention to provide an
apparatus and method for switching a navigation mode between a
vehicle navigation mode and a personal navigation mode in a
navigation device supporting vehicle navigation and personal
navigation, in which the navigation device determines whether a
user uses a vehicle, such as a car, or walks. Upon such
determination the navigation device automatically performs the
appropriate mode switching.
[0013] According to one aspect of the present invention, there is
provided an apparatus for switching a navigation mode between a
vehicle navigation mode and a personal navigation mode in a
navigation device. The apparatus includes a personal navigation
algorithm for implementing a personal navigation mode, a vehicle
navigation algorithm for implementing a vehicle navigation mode, an
external device interface for connecting the navigation device and
an external device, a speed measuring unit for providing a speed of
the navigation device, a step detecting unit for detecting a step
according to movement of the navigation device, and a navigation
algorithm controller for switching the navigation mode between the
vehicle navigation mode and the personal navigation mode. The
switching of the navigation mode is done according to whether the
navigation device is mounted in a navigation device holder through
the external device interface, whether the speed of the navigation
device is greater than a predetermined speed threshold, and whether
a step is detected by the step detecting unit.
[0014] According to another aspect of the present invention, there
is provided a method for switching a navigation mode between a
vehicle navigation mode and a personal navigation mode in a
navigation device. The method includes executing a navigation
program upon request from a user and determining whether the
navigation device is mounted in a navigation device holder,
switching the navigation mode to the vehicle navigation mode if the
navigation device is mounted in the navigation device holder and
acquiring a speed of the navigation device if the navigation device
is not mounted in the navigation device holder, switching the
navigation mode to the vehicle navigation mode if the speed of the
navigation device is greater than a predetermined speed threshold
and acquiring a measured acceleration of the navigation device if
the speed of the navigation device is less than a predetermined
speed threshold, and determining whether a step is detected
according to the recognition result, switching the navigation mode
to the vehicle navigation mode if a step is not detected, and
switching the navigation mode into the personal navigation mode if
a step is detected.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other objects, features, and advantages of
certain exemplary embodiments of the present invention will be more
apparent from the following description taken in conjunction with
the accompanying drawings, in which:
[0016] FIG. 1 is a block diagram of a navigation device according
to the present invention;
[0017] FIG. 2 is a flowchart illustrating mode switching between a
vehicle navigation mode and a personal navigation mode according to
a first embodiment of the present invention;
[0018] FIG. 3 is a flowchart illustrating mode switching between a
vehicle navigation mode and a personal navigation mode according to
a second embodiment of the present invention;
[0019] FIG. 4 is a flowchart illustrating mode switching between a
vehicle navigation mode and a personal navigation mode according to
a third embodiment of the present invention;
[0020] FIG. 5 is a flowchart illustrating mode switching between a
vehicle navigation mode and a personal navigation mode according to
a fourth embodiment of the present invention; and
[0021] FIG. 6 is a flowchart illustrating a process of setting a
speed threshold and a step detected number threshold for a
vehicle/personal mode determination according to the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The matters defined in the description such as a detailed
construction and elements are provided to assist in a comprehensive
understanding of the exemplary embodiments of the invention.
Accordingly, those of ordinary skill in the art will recognize that
various changes and modifications of the embodiments described
herein can be made without departing from the scope and spirit of
the invention. Similarly those of ordinary skills in the art will
recognize that a preferred embodiment of the present invention is
provided with reference to a vehicle navigation method and device,
an example of which is a car navigation method and device. Also,
descriptions of well-known functions and constructions are omitted
for clarity and conciseness.
[0023] In the present invention, a navigation device performing
navigation of a vehicle, such as a car, and personal navigation and
automatically switching between vehicle navigation and personal
navigation modes is provided. For simplicity of explanation, the
vehicle navigation device and method of the present invention will
hereinafter be referred to as a car navigation device and
method.
[0024] FIG. 1 is a block diagram of a navigation device according
to the present invention. Referring to FIG. 1, the navigation
device includes a Global Positioning System (GPS) receiver 102, an
accelerometer 104, a navigation algorithm controller 112, a user
interface 106, and an external device interface 108.
[0025] The GPS receiver 102 receives a GPS signal from a GPS
satellite and provides a GPS speed of the navigation device using
position information and time information included in the GPS
signal.
[0026] The accelerometer 104 may be a three-axis accelerometer and
measures as well as outputs a speed according to movement of the
navigation device.
[0027] The user interface 106 may be an input device such as a
keypad or a touch panel and interfaces with a user. For example,
the user interface 106 receives a navigation program execution
request from the user and transmits the same to the navigation
algorithm controller 112.
[0028] The external device interface 108 is a connector between the
navigation device and an external device and performs interfacing
between the navigation device and an external device in a serial
communication manner such as Universal Asynchronous Receiver
Transmitter (UART) or Universal Serial Bus (USB). For example, the
external device interface 108 connects and interfaces the
navigation device with a navigation device holder 110 or a
navigation device charger (e.g., a cigar jack).
[0029] The navigation algorithm controller 112 which includes a car
navigation algorithm 114 and a personal navigation algorithm 116,
executes a corresponding navigation program in response to a
navigation program execution request, and determines whether a
current mode is a car mode or a personal mode according to a
predetermined criterion.
[0030] For example, the navigation algorithm controller 112
determines whether the current mode is the car mode or the personal
mode according to whether the navigation device is mounted in the
navigation device holder 110, the GPS speed provided by the GPS
receiver 102 is higher than a predetermined speed, and a step is
detected based on a measured acceleration. If the current mode is
determined to be the car mode, the navigation algorithm controller
112 switches a navigation mode to a car navigation mode that
implements the car navigation algorithm 114. If the current mode is
determined to be the personal mode, the navigation algorithm
controller 112 switches a navigation mode to a personal navigation
mode that implements the personal navigation algorithm 116.
[0031] In switching between the car navigation mode and the
personal navigation mode, the car navigation algorithm 114 and the
personal navigation algorithm 116 provide position information,
speed information, and azimuth information to an algorithm
corresponding to the switched mode. In other words, in switching
between the car navigation mode and the personal navigation mode,
the car navigation algorithm 114 and the personal navigation
algorithm 116 provide acceleration data logs measured by the
accelerometer 104 for 1-10 seconds and position, speed, and azimuth
data logs measured by a GPS for 1-10 seconds to an algorithm
corresponding to the switched mode. A data rate time unit is used
in the car navigation algorithm 114 and the personal navigation
algorithm 116. A data log measured for 1 second is provided when a
data rate is higher than 50 Hz and a data log measured for 10
seconds is provided when a data rate is lower than 10 Hz.
[0032] Previous sensor data is required for calculation of a
reference value or a median value of a sensor in the car navigation
mode and is required for step detection and pace estimation in the
personal navigation mode. Thus, previous sensor data is exchanged
in switching between the car navigation mode and the personal
navigation mode.
[0033] The data rate means the data rate of a sensor and is a
period of the output of an accelerometer and a terrestrial magnetic
sensor. The car navigation algorithm 114 and the personal
navigation algorithm 116 require sensor values whose number is
greater than a predetermined number, i.e., successive sensor values
whose number is greater than a predetermined number. Thus, data
measured for a long time (e.g., 10 seconds) is secured in case of
low data rate and data measured for a short time (e.g., 1 second)
is secured in case of high data rate to fit in the required total
number of data values.
[0034] For example, the car navigation algorithm 114 terminates car
navigation upon request for switching to the personal navigation
mode while performing car navigation and provides position, speed,
and azimuth data of the navigation device to the personal
navigation algorithm 116. The personal navigation algorithm 116
subsequently then performs personal navigation from car navigation,
using the data provided from the car navigation algorithm 114.
[0035] The personal navigation algorithm 116 terminates personal
navigation upon request for switching to the car navigation mode
while performing personal navigation and provides position, speed,
and azimuth data of the navigation device to the car navigation
algorithm 114. The car navigation algorithm 114 subsequently then
performs car navigation from personal navigation, using the data
provided from the personal navigation algorithm 116.
[0036] Hereinafter is a description of a method for switching a
navigation mode between the car navigation mode and the personal
navigation mode in a navigation device according to the present
invention.
[0037] According to a first embodiment of the present invention,
the navigation device performs mode switching between the car
navigation mode and the personal navigation mode according to
whether the navigation device is mounted in the navigation device
holder 110.
[0038] FIG. 2 is a flowchart illustrating mode switching between
the car navigation mode and the personal navigation mode according
to the first embodiment of the present invention. Referring to FIG.
2, the navigation device executes a navigation program in response
to a navigation program execution request from a user in step 202.
Upon execution of the navigation program, the navigation device
determines whether it is mounted in the navigation device holder
110 in step 204. The navigation device can make a determination
using a mechanical method and a message transmission method.
[0039] According to the mechanical method, the navigation device
determines whether it is mounted in the navigation device holder
110 by checking if a button in a portion of the navigation device
that physically contacts the navigation device holder 110 is
depressed. The navigation device determines that it is mounted in
the navigation device holder 110 if the button is depressed. If the
button is not depressed, the navigation device determines that it
is separated from the navigation device holder 110.
[0040] According to the message transmission method, the navigation
device transmits a holder ID request message to the navigation
device holder 110 through the external device interface 108 and
determines whether it is mounted in the navigation device holder
110 by checking if a holder ID or an interrupt message is received
as a response to the request message. If the holder ID or the
interrupt message is received, the navigation device determines
that it is mounted in the navigation device holder 110. If the
holder ID or the interrupt message is not received, the navigation
device determines that it is separated from the navigation device
holder 110. However, the navigation device may fail to receive the
holder ID or the interrupt message from the navigation device
holder 110. Thus, every 10 seconds the navigation device
repetitively transmits the holder ID request message to the
navigation device holder 110. Upon receipt of the holder ID or the
interrupt message, the navigation device determines that it is
mounted in the navigation device holder 110. When the navigation
device is determined to be mounted in the navigation device holder
110, it continuously transmits the holder ID request message every
30 seconds to the navigation device holder 110 to determine whether
it is separated from the navigation device holder 110.
[0041] If the navigation device is determined to be mounted in the
navigation device holder 110, it switches a navigation mode to the
car navigation mode in step 206 and then performs car navigation
using the car navigation algorithm 114.
[0042] If the navigation device is determined to be separated from
the navigation device holder 110, it switches a navigation mode to
the personal navigation mode in step 208 and then performs personal
navigation using the personal navigation algorithm 116.
[0043] According to a second embodiment of the present invention,
the navigation device performs mode switching between the car
navigation mode and the personal navigation mode according to
whether a GPS speed provided by the GPS receiver 102 is higher than
a predetermined speed.
[0044] FIG. 3 is a flowchart illustrating mode switching between
the car navigation mode and the personal navigation mode according
to the second embodiment of the present invention. Referring to
FIG. 3, the navigation device executes a navigation program in
response to a navigation program execution request from the user in
step 402. Upon execution of the navigation program, the navigation
device acquires GPS speed information from the GPS receiver 102 in
step 404.
[0045] The navigation device then determines whether the acquired
GPS speed is high in step 406. In other words, the navigation
device determines whether the acquired GPS speed is higher than a
predetermined speed threshold. The GPS speed has a limit in the
personal navigation mode, since a user will either walk or run
while carrying the navigation device. Thus, the navigation device
assumes that the maximum speed of a walker is about 25 km/h and
sets 25 km/h as a speed threshold. The navigation device determines
that the GPS speed is high when the GPS speed is higher than the
speed threshold. If the GPS speed is lower than the speed
threshold, the navigation device determines that the GPS speed is
low.
[0046] When the GPS speed is high, the navigation device determines
that the current mode is the car mode and switches a navigation
mode to the car navigation mode in step 408. The navigation device
then performs car navigation using the car navigation algorithm
114. If the GPS speed is not high, the navigation device determines
that the current mode is the personal mode and switches a
navigation mode to the personal navigation mode in step 410. The
navigation device then performs personal navigation using the
personal navigation algorithm 116.
[0047] According to a third embodiment of the present invention,
the navigation device performs mode switching between the car
navigation mode and the personal navigation mode according to
whether a step is detected using an output of the accelerometer
104.
[0048] FIG. 4 is a flowchart illustrating mode switching between
the car navigation mode and the personal navigation mode according
to the third embodiment of the present invention. Referring to FIG.
4, the navigation device executes a navigation program in response
to a navigation program execution request from the user in step
502. The navigation device acquires an acceleration measured by the
accelerometer 104 in step 504.
[0049] The navigation device recognizes a step pattern using the
measured acceleration in step 506. When a user walks, an
acceleration measured by the accelerometer 104 is output as a
frequency waveform of a predetermined pattern in which an
acceleration component toward the center of the earth, i.e., an
acceleration magnitude toward the center of the earth is greater
than .+-.0.5 g(g=9.8 m/s, earth gravitational acceleration).
However, when the user uses a car, a specific waveform greater than
0.5 g of an acceleration measured by the accelerometer 104 is not
output as a frequency waveform of the predetermined pattern. Thus,
the navigation device checks if an acceleration measured by the
accelerometer 104 is output as a frequency waveform of the
predetermined pattern to recognize a step pattern. A step detection
algorithm for recognizing the step pattern may be various
well-known step detection methods including a zero-crossing
method.
[0050] The navigation device determines whether a step is detected
in step 508. If a step is not detected, the navigation device
determines that the user is not walking and switches a navigation
mode to the car navigation mode in step 510. The navigation device
implements the car navigation mode using the car navigation
algorithm 114. If a step is detected, the navigation device
determines that the user is walking and switches a navigation mode
to the personal navigation mode in step 512. The navigation device
implements the personal navigation mode using the personal
navigation algorithm 116.
[0051] According to a fourth embodiment of the present invention,
the navigation device performs mode switching between the car
navigation mode and the personal navigation mode according to
whether the navigation device is mounted in the navigation device
holder 110, whether a GPS speed provided by the GPS receiver 102 is
higher than a predetermined speed, and whether a step is detected
using an output of the accelerometer 104. According to a fifth
embodiment of the present invention, since a navigation mode is
likely to be the car navigation mode when the user is on a driveway
or an express highway, a reference value for a GPS speed and a
reference value for an acceleration measured by the accelerometer
104 for car/personal mode determination are set useful for
determination of the car navigation mode. Mode switching between
the car navigation mode and the personal navigation mode is
performed according to the reference values.
[0052] FIG. 5 is a flowchart illustrating mode switching between
the car navigation mode and the personal navigation mode according
to the fourth embodiment of the present invention. Referring to
FIG. 5, the navigation device executes a navigation program in
response to a navigation program execution request from the user in
step 602.
[0053] The navigation device determines whether it is mounted in
the navigation device holder 110 in step 604 as described about
step 204 with reference to FIG. 2.
[0054] If the navigation device is mounted in the navigation device
holder 110, it determines that the current mode is the car mode and
switches the navigation mode to the car navigation mode in step
620. The navigation device then performs car navigation using the
car navigation algorithm 114.
[0055] If the navigation device is not mounted in the navigation
device holder 110, it sets a speed threshold .alpha. and a step
detected number threshold .beta. for car/personal mode
determination in step 608.
[0056] FIG. 6 is a flowchart illustrating a process of setting the
speed threshold .alpha. and the step number detection threshold
.beta. for car/personal mode determination according to the present
invention. Referring to FIG. 6, the navigation device detects a
user's position in step 702. The navigation device can detect the
user's position using a GPS signal received by the GPS receiver
102. The navigation device determines whether the user's position
is a road way in step 704. In other words, the navigation device
determines whether the user is on a driveway or an express highway.
This is because the user is likely to use car navigation when on a
road way and is likely to use personal navigation when not on a
road way.
[0057] If the user is on a road way, the navigation device sets the
GPS speed threshold a greater than a default value and the step
detected number threshold .beta. less than a default value. In
other words, when the user is on a road way, the navigation device
sets the GPS speed threshold .alpha. and the step detected number
threshold .beta. to values useful for determination of the car
navigation mode.
[0058] When the user is not on a road way, the navigation device
sets the GPS speed threshold .alpha. and the step detected number
threshold .beta. to default values in step 708 or may set the GPS
speed threshold .alpha. less than a default value and the step
detected number threshold .beta. greater than a default value
usefully for determination of the personal navigation mode.
[0059] After setting the GPS speed threshold .alpha. and the step
detected number threshold .beta., the navigation device acquires
GPS speed information from the GPS receiver 102 in step 610.
[0060] The navigation device determines whether the acquired GPS
speed is greater than the set GPS speed threshold .alpha. in step
612. If the acquired GPS speed is greater than the set GPS speed
threshold .alpha., it means that the GPS speed is high. Thus, the
navigation device determines that the current mode is the car mode
and switches a navigation mode to the car navigation mode in step
620. The navigation device then performs car navigation using the
car navigation algorithm 114.
[0061] If the acquired GPS speed is less than the set GPS speed
threshold .alpha., it means that the GPS speed is low. Thus, the
navigation device determines that the current mode is not the car
mode and performs step detection for car/personal mode
determination in step 614. In other words, the navigation device
recognizes a step pattern using an acceleration measured by the
accelerometer 104 and performs step detection according to the
recognition result.
[0062] The navigation device determines whether the number of
detected steps is greater than the set step detected number
threshold .beta. in step 616. If the number of detected steps is
less than the set step detected number threshold .beta., the
navigation device determines that the user is not walking and
switches the navigation mode to the car navigation mode in step
620. The navigation device then performs car navigation using the
car navigation algorithm 114.
[0063] If the number of detected steps is greater than the set step
detected number threshold .beta., the navigation device determines
that the user is walking and switches the navigation mode to the
personal navigation mode in step 618. The navigation device then
performs personal navigation using the personal navigation
algorithm 116.
[0064] As described above, according to the present invention,
switching between a car navigation mode and a personal navigation
mode is automatically performed in a single navigation device,
thereby alleviating inconvenience of requiring the user's manual
mode switching.
[0065] Moreover, in switching between the car navigation mode and
the personal navigation mode, an algorithm provides position,
velocity, and azimuth data of the navigation device to another
algorithm corresponding to a switched mode. Thus, personal
navigation is subsequently automatically performed from car
navigation or car navigation is subsequently automatically
performed from personal navigation.
[0066] Furthermore, once a navigation program is executed, the
navigation device automatically switches between the car navigation
mode and the personal navigation mode. Thus, the user does not need
to perform manual mode switching on a way from a departure to a
destination.
[0067] While the present invention has been shown and described
with reference to preferred embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention.
* * * * *