JP2004125542A - Navigation system, electronic apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation system and its program capable of efficiently compressing the movement track information. <P>SOLUTION: The navigation system is provided with a ring buffer 22 for storing logs; a GPS computing device 18 for determining a present location; a moving direction detecting device 19 for detecting the moving direction; and a computing means 12 for capturing the moving direction outputted from the moving direction detecting device 19 at prescribed periods, determining the amount of change in the moving direction during the period, integrating it, storing, in the ring buffer 22 for storing logs, location information of one period earlier with respect to one from the GPS computing device 18 when the integrated value exceeds a prescribed threshold value, and clearing the integrated value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a navigation device, an electronic device incorporating the navigation device, and a program.
[0002]
[Prior art]
2. Description of the Related Art Some conventional navigation devices include an absolute position measuring device and a moving direction change detecting device, and record moving trajectory information. Some navigation devices use a ring buffer to record movement trajectory information. The capacity of the ring buffer is small due to restrictions such as cost and size of the housing. For this reason, it is not possible to record long-term movement trajectory information. Therefore, in order to record the long-time moving trajectory information, it is necessary to compress the moving trajectory information. The movement trajectory information is represented by a curve, and the geometric feature of the curve is one piece of information.
[0003]
By the way, in this type of navigation device, as a device that compresses and stores the movement trajectory data, for example, “a positioning unit that measures the current position of a moving object to generate current position data, A navigation device that includes trajectory data storage means for storing the current position data as trajectory data for each movement, and azimuth detection means for detecting a traveling azimuth; A traveling azimuth change position determining unit that determines the presence or absence of a change in the traveling azimuth of the moving object based on a detection signal from the detection unit and detects the traveling azimuth change position; And a trajectory data compressing means for compressing data while leaving only trajectory data in a predetermined range before and after. Patent Document 1).
[0004]
[Patent Document 1]
JP-A-5-40440
[Problems to be solved by the invention]
In the above-described conventional technology (Patent Document 1), since the change of the traveling direction at the moment is detected and the storage point is determined based on the change amount, the movement trajectory based on the compressed and stored data and the actual movement trajectory are determined. There is a case where the moving trajectory is greatly different. For example, in the case of moving along a gentle arc, the amount of change at the moment is small, so that the number of points to be stored is small, and the moving trajectory based on the compressed and stored data greatly differs from the actual moving trajectory.
[0006]
The present invention has been made in order to solve such a problem, and provides a navigation device capable of efficiently compressing movement trajectory information, an electronic device incorporating the navigation device, and a program therefor. The purpose is to:
[0007]
[Means for Solving the Problems]
A navigation device according to the present invention fetches a moving direction output from the moving direction detecting means at a predetermined cycle, a data storing means, a position detecting means for obtaining a current position, a moving direction detecting means for detecting a moving direction. Then, the amount of change in the moving direction during the cycle is obtained and integrated, and when the integrated value becomes larger than a predetermined threshold value (threshold value), the position detecting means before the predetermined cycle by a predetermined cycle is provided. And data processing means for storing the position information from the data storage means in the data storage means and clearing the integrated value. With this configuration, the moving direction output from the moving direction detecting means is taken in at a predetermined cycle, the change amount of the moving direction during the cycle is integrated, and the integrated value is larger than a predetermined threshold value. When it becomes larger, the position information (latitude, longitude) before a predetermined period with respect to the period is stored in the data storage means, and the displacement point is appropriately detected to compress the movement trajectory information. ing. In particular, even when the amount of change at the moment is small, such as when moving along a gentle arc, the change amount is integrated as described above to detect the storage point, so that the compression point is stored. The degree of coincidence between the movement locus based on the input data and the actual locus is high.
[0008]
The navigation device according to the present invention further includes integrated value storage means for storing an integrated value of the amount of change in the moving direction, wherein the calculating means obtains the amount of change in the moving direction and adds the obtained amount to the integrated value of the integrated value storage means. Calculating the integrated value of the change amount in the moving direction, further storing and updating the integrated value in the integrated value storage means, and when the integrated value becomes larger than a predetermined threshold value, the integrated value storage means The process of repeating the process of clearing the integrated value of is performed, so that the amount of change in the moving direction is reliably integrated, and the storage point is appropriately detected.
[0009]
Further, in the navigation device according to the present invention, when the integrated value becomes larger than a predetermined threshold value, the calculating means transmits the position information from the position detecting means one cycle before the cycle to the data. Store in storage means. When the integrated value becomes larger than a predetermined threshold value, there is a displacement point at a point one cycle before the cycle, and the position information is stored in the data storage means. Since the displacement points are detected and stored in this way, the degree of coincidence between the movement locus based on the compressed and stored data and the actual movement locus becomes high.
[0010]
Further, in the navigation device according to the present invention, the calculation means integrates the absolute value of the amount of change in the moving direction, so that the degree of coincidence with the actual moving trajectory is high.
Further, in the navigation device according to the present invention, the data storage means includes a ring buffer. Since the compressed data is composed of a group of displacement points, even if the storage capacity of the ring buffer is small, it is possible to store the data of the movement trajectory for a long time.
Further, in the navigation device according to the present invention, the moving direction detecting means obtains the moving direction based on the trajectory of the output of the position detecting means, and it is not necessary to separately provide a component for the moving direction detecting means. Therefore, the device can be simplified.
Further, in the navigation device according to the present invention, the position detecting means is a position detecting means using GPS, and high-accuracy position detection using GPS is enabled.
Further, an electronic device according to the present invention incorporates the above navigation device, and its usefulness can be further enhanced by adding a navigation function to the electronic device.
Further, the program according to the present invention causes the central processing unit to execute the arithmetic means of the navigation device, and the functions of the arithmetic means can be realized by the program, thereby simplifying the circuit.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a navigation device 10 according to the first embodiment of the present invention. The navigation device 10 includes a calculation unit (central processing unit: CPU) 12. The navigation device 10 includes a GPS receiving device 16 and a GPS calculating device 18. The GPS calculating device 18 is connected to a calculating means (CPU) 12 and outputs a calculation result to the calculating means (CPU) 12. I do. The calculation means (CPU) 12 stores a moving direction detecting device 19, an operation unit 20, a log buffer ring buffer 22, a map data memory 24, a moving direction change amount adding memory 25, a measurement information storing buffer 26, a program, and the like. The memory 28, the display control unit 30, and the audio processing unit 34 are connected to each other. A display unit (display) 32 is connected to the display control unit 30, and a sound generation unit 36 is connected to the sound processing unit 34.
[0012]
In the present embodiment, the current position (absolute position) and the like are grasped using a GPS (global positioning system), but this GPS uses a satellite that covers the entire earth. In the positioning system, the surface of each vertex is a group of satellites orbiting at an altitude of 18183 km from the surface of the ground is defined as the bottom of the pyramid, and the apex of the pyramid formed by the ridgeline that receives and measures signals from these satellites is defined as This is a system that obtains the current position of the receiving device. In this system, 24 GPS satellites orbit each in 6 orbits with respect to the earth.
[0013]
In the navigation device 10 of FIG. 1, the GPS receiving device 16 receives radio waves from a plurality of GPS satellites orbiting the earth from the GPS antenna 16a and outputs the radio waves to the GPS arithmetic device 18. The GPS operation device 18 obtains position information (latitude, longitude, altitude) of the current position based on a signal from the GPS reception device 16. The moving direction detecting device 19 detects a moving direction when the navigation device 10 is carried and moved, and is constituted by, for example, an angular velocity sensor, a gyroscope, and the like. The operation unit 20 is for inputting various operation signals to the calculation unit 12, and includes various keys such as a key for map search and enlargement / reduction, a cross cursor key including left, right, up, and down keys. And may be arranged in the form of a touch panel on the screen of the display unit 32, for example.
[0014]
The log storage ring buffer 22 is a storage device in which movement information is stored. As the map data memory 24, a non-volatile memory storing map data and the like is used. By the way, the map database in the case of a vehicle navigation device is managed as a map (map figure) divided into regions of appropriate longitude and latitude widths according to the scale level, and Each figure leaf includes, for example, (a) a background layer for displaying roads, rivers, parks, etc., (b) a character / symbol layer for displaying municipal names, road names, symbols, etc., and (c) a road layer. It is configured. The road layer includes link information and the like for specifying a road position. A road is indicated by a set of vertices (nodes) expressed by latitude and longitude coordinates. Called a link. In addition, this road layer includes information such as intersection information and the distance between intersections. The map image displayed on the display unit is based on a signal formed by synthesizing each layer of a plurality of leaves (map pieces). Since the navigation device of this embodiment is assumed to be portable, a CD-ROM or the like cannot be used, and the storage capacity of the map data memory 24 cannot be large. Simplified map data is stored as compared with the stored map data.
[0015]
The moving direction change amount adding memory 25 is a storage device used when the calculating means 12 calculates and integrates changes in the moving direction based on the moving direction output from the moving direction detecting device 19. The measurement information storage buffer 26 is a memory area used in the process of performing the thinning process by the arithmetic means 12, and is the position information of the point last saved in the log storage ring buffer 22 and the position of the point one cycle before (storage target). The position information and the moving direction, and the position information and the moving direction of the current point are stored, respectively. The memory 28 stores a program for performing arithmetic processing of the arithmetic means 12, and particularly stores a program for performing thinning processing (compression processing). The display control unit 30 fetches desired map data or the like selected by a key operation of the operation unit 20 from the map data memory 24, and displays the map image on the display unit 32, for example, such that the current position is at the center. The audio processing unit 34 processes the audio signal based on the arithmetic processing of the arithmetic unit 12 and outputs the processed audio signal from the audio generating unit 36. For example, when the vehicle reaches the destination, the voice generating unit 36 guides the user to that effect.
[0016]
The calculating means 12 reads the map data of the corresponding area from the map data memory 24 based on the position information and the moving direction of the current location, draws a map image based on the map data, and outputs the map image to the display control unit 30. The display control unit 30 causes the display unit 32 to display the map image such that the traveling direction is, for example, upward in the display screen and the current position is in the center. At this time, the display unit 32 also displays a cursor mark, a current position mark, a planned traveling (moving) route, and the like on the map image. In addition, the arithmetic unit 12 outputs a voice signal to the voice processing unit 34 as necessary, and performs voice guidance by the voice generation unit 36 via the voice processing unit 34.
[0017]
When a destination (a transit point or a final destination) is designated by operating the operation unit 20, the calculating means 12 calculates a traveling route from the departure point (the current position) to the destination (the transit point or the final destination). Can be calculated. In that case, the arithmetic means 12 reads out the map data from the departure point (current position) to the destination (transit point, final destination) in the map data memory 24 and refers to the read out map data, for example, Dijkstra Simulation, horizontal search method, etc., to find the optimal travel schedule (schedule) that connects the current location and the destination (transit point, final destination) in the shortest time, and to calculate the travel schedule (schedule) The data of the route to be traveled (scheduled to be moved), which is a combination of the route node row, the head departure place data and the tail destination data, is stored in the log storage ring buffer. When the map image is displayed on the display unit, the data of the planned travel (scheduled) route is used to guide a user by highlighting a route (road) corresponding to the planned travel (scheduled) route, for example. Can be The data of the above-mentioned travel schedule (scheduled travel) may be obtained at the start of navigation. However, since the destination may be changed or the stop-off location may be set halfway, Is also required as appropriate. Of course, the navigation may be performed without finding the scheduled traveling (scheduled) route.
[0018]
Next, the operation of the navigation device 10 according to the first embodiment will be described. When the user carries the navigation device 10 and turns on the power (not shown) and starts moving, the GPS calculation device 18 obtains the position information of the current position and outputs it to the calculation means 12, and the movement direction detection device 19 The moving direction is obtained and output to the calculating means 12. The calculating means 12 reads the map data of the corresponding area from the map data memory 24 as described above based on the position information of the current position from the GPS calculating device 18 and the moving direction from the moving direction detecting device 19, and The display controller 30 draws a map image based on the data and outputs the map image to the display controller 30. The display controller 30 displays the map image such that the traveling direction is directed upward in the display screen and the current position is in the center. , The position information and the moving direction of the current location are stored in the measurement information storage buffer 26, and a thinning-out process of FIG.
[0019]
FIG. 2 is a flowchart showing the process of the thinning process by the calculating means 12. In this flowchart, the processing is cyclically performed at a predetermined cycle. The position information of the departure point is unconditionally stored in the log storage ring buffer 22.
(S11) The calculating means 12 obtains a change amount in the moving direction from the difference between the moving direction of the current position stored in the measurement information storage buffer 26 and the moving direction one cycle before.
(S12) The calculating means 12 adds the change amount in the moving direction obtained in the above processing (S11) to the integrated value of the change amount stored in the moving direction change amount adding memory 25, and calculates the moving direction change amount. The integrated value of the change amount in the addition memory 25 is updated. In addition, the amount of change at the time of addition is an absolute value, and the amount of change is integrated regardless of the change in any of the left and right directions. When the amount of change is added or subtracted according to the left and right directions, the difference between the trajectory based on the thinned data and the actual trajectory may be large, and thus the absolute value of the amount of change in the moving direction is thus obtained. Is added to avoid a large difference from the actual trajectory.
[0020]
(S13) The calculation means 12 determines whether the change amount stored in the movement direction change amount addition memory 25 is larger than a predetermined threshold. If the amount of change is smaller than the predetermined threshold, the thinning is performed, and the thinning processing ends without storing the data of the current location in the ring buffer 22 for log storage.
(S14) If the calculation means 12 determines that the change amount stored in the movement direction change amount addition memory 25 is larger than the predetermined threshold, the calculation means 12 stores the change amount before one cycle stored in the measurement information storage buffer 26. Is stored in the log storage ring buffer 22. The data stored at this time are latitude, longitude, altitude, and positioning time. The latitude, longitude, and altitude information are obtained from the GPS arithmetic unit 18, and the positioning time is obtained by the clock function of the arithmetic unit 12. In this case, the reason why the position information one cycle before is stored instead of the position information of the current location is that the position one cycle before corresponds to the displacement point.
(S15) The calculation means 12 clears the moving direction change amount addition memory 25 and ends the thinning process in preparation for the next change amount integration.
[0021]
FIG. 3 is an explanatory diagram showing the relationship between the movement locus and the storage of data. In the figure, when it is determined that the added value of the change amount exceeds a predetermined threshold value at the point P4, the position information of the point P3 one cycle before that is stored. Thereafter, the change amounts of the points P5 to P7 are added, and when it is determined that the added value of the change amount has exceeded a predetermined threshold value at the time of the point P7, the position information of the point P6 one cycle before that is determined. Is saved. Thereafter, the thinning process is performed in the same manner, and the position information of the points P9, P14, P16, P19, P21, and P23 in FIG. 3 is stored. Although the interval between the points P9 to P14 is large, the trajectory during this period is almost straight ahead and is not saved.
[0022]
FIG. 4 is an explanatory diagram of data (compressed data) stored in the log storage ring buffer 22. As shown in the figure, each data is composed of latitude, longitude, altitude, and positioning time.
FIG. 5 is a diagram showing a specific example of data stored in the log storage ring buffer 22. The positioning time is an integrated second based on 00:00:00 on January 1, 2000.
FIG. 6 illustrates the data of FIG. The broken line indicates the movement locus of the data before compression, and the solid line indicates the movement locus of the data after compression. It can be seen that the broken line and the actual solid line match well.
[0023]
As described above, according to the first embodiment, the moving direction output from the moving direction detecting device 19 is acquired at a predetermined cycle, and the amount of change in the moving direction during the cycle is integrated. When the threshold value becomes larger than the threshold value, the position information one cycle before the cycle is stored in the ring buffer 22 for log storage, and the displacement point is appropriately detected to compress the movement trajectory information. Is going. For this reason, for example, even when the amount of change at the moment is small, such as when moving in a gentle arc, the amount of change is integrated and the storage point is detected as described above. The degree of coincidence between the movement trajectory based on the compressed and stored data and the actual trajectory is high.
[0024]
Embodiment 2. FIG.
In the first embodiment described above, an example is described in which the moving direction detecting device 19 is used to determine the moving direction. However, the calculating means 12 uses the moving trajectory obtained by connecting the position information from the GPS calculating device 18. You may make it obtain | require based on it. Alternatively, when the GPS operation device 18 has a similar function, the output (azimuth output) may be used. In the first embodiment described above, the data stored in the log storage ring buffer 22 does not need to be constantly stored in the navigation device 10, but is stored in a memory card, and only when necessary. The data may be taken in by mounting the memory card. In the first embodiment, the example of the log storage ring buffer 22 has been described as a data storage device for storing data after compression. However, in the present invention, another type of storage device may be used. Good. Also, an example in which a GPS system is used as the position detecting means has been described, but a cellular phone such as a D (Differential) -GPS or a PHS may be used. Further, the navigation device 10 of the above-described embodiment may be built in an electronic device such as a PHS, a mobile phone, or a personal digital assistant (PDA).
[0025]
Embodiment 3 FIG.
Although the first embodiment does not refer to receiving real-time information from a road traffic information communication system such as VICS or ATIS, the present invention excludes reception from a road traffic information communication system. Instead, real-time information may be received from the road traffic information communication system (in that case, a receiving facility is required). This road traffic information communication system provides users with real-time information such as road construction information, accident information, traffic congestion information, and parking lot congestion information by radio communication such as quasi-microwave beacon and FM multiplex broadcasting. By displaying such information on the screen when it is desired, or by automatically displaying the information on the screen, various types of traffic information can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a navigation device according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing an operation example of the navigation device in FIG. 1;
FIG. 3 is an explanatory diagram showing a relationship between a movement locus and data storage.
FIG. 4 is a configuration diagram of data after compression.
FIG. 5 is a diagram showing a specific example of data after compression.
FIG. 6 is a diagram showing a movement locus of data before and after compression.
[Explanation of symbols]
Reference Signs List 10 navigation device, 12 arithmetic means, 16 GPS receiving device, 16a antenna, 18 GPS arithmetic device, 19 moving direction detecting device, 20 operation unit, 22 log buffer ring buffer, 24 map data memory, 25 moving direction change amount adding memory , 26 measurement information storage buffer, 28 memory, 30 display control unit, 32 display unit, 34 audio processing unit.

Claims (9)

Data storage means;
Position detection means for determining the current position;
Moving direction detecting means for detecting a moving direction;
The moving direction output from the moving direction detecting means is captured at a predetermined cycle, the amount of change in the moving direction during the cycle is obtained and integrated, and when the integrated value becomes larger than a predetermined threshold, A navigation device, comprising: a position information from the position detection unit before a predetermined period with respect to a period is stored in the data storage unit; and a calculation unit that clears the integrated value. Integrated value storage means for storing an integrated value of the change amount in the moving direction, wherein the calculating means obtains the change amount in the moving direction and adds the obtained value to the integrated value in the integrated value storage means to integrate the change amount in the moving direction; A process of obtaining a value, further storing and updating the integrated value in the integrated value storage means, and clearing the integrated value of the integrated value storage means when the integrated value becomes larger than a predetermined threshold value. The navigation device according to claim 1, wherein the navigation device is repeated. The calculating means stores the position information from the position detecting means one cycle before the cycle in the data storage means when the integrated value becomes larger than a predetermined threshold value. The navigation device according to claim 1. The navigation device according to any one of claims 1 to 3, wherein the calculation means integrates an absolute value of a change amount in a moving direction. 5. The navigation device according to claim 1, wherein said data storage means comprises a ring buffer. The navigation device according to claim 1, wherein the moving direction detecting unit obtains a moving direction based on a locus of an output of the position detecting unit. The navigation device according to claim 1, wherein the position detection unit is a position detection unit using a GPS. An electronic device comprising the navigation device according to claim 1. A non-transitory computer-readable storage medium storing a program for causing a central processing unit to execute the arithmetic unit of the navigation device according to claim 1.

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