JP4646727B2 - Self-vehicle position calculation device and calculation method thereof - Google Patents

Description

  The present invention relates to a vehicle position calculation device in a navigation device, and more particularly, to a vehicle position calculation device that receives travel distance information used for self-contained navigation by an in-vehicle communication bus.

  The navigation device detects the vehicle position, draws map data around the vehicle position on the display, displays the vehicle mark on the map, and scrolls the map when the vehicle position changes. It has a function to guide the road map. Further, the optimum route to the destination is searched, the searched route is displayed on the display, and the arrival time to the destination by the searched route is also displayed.

  As navigation devices, a self-contained navigation method for calculating the vehicle position from a distance sensor and a direction sensor mounted on the vehicle and a method for calculating the vehicle position by GPS positioning using a satellite have been put into practical use. A distance sensor for self-contained navigation uses, for example, a vehicle speed pulse, and the vehicle speed pulse outputs a pulse signal every time the vehicle travels a certain distance. In addition, for example, a gyroscope is used as the direction sensor. The calculation or update of the vehicle position by the self-contained navigation is calculated by combining the movement distance obtained by the distance sensor and the movement direction vector obtained by the direction sensor.

  In the self-contained navigation, the vehicle position can be calculated with a relatively simple configuration, but since it is a relative position detection, it is difficult to perform highly accurate position measurement. That is, as the vehicle travels, errors accumulate and the accuracy of the vehicle position deteriorates. In order to compensate for this deterioration in accuracy, so-called map matching processing using road (link) data included in the map database is performed. The link data includes the latitude and longitude information of the road, and the vehicle position is calibrated or corrected by collating the vehicle position calculated by the independent navigation with the link data.

  On the other hand, GPS positioning measures the distance of a plurality of GPS satellites orbiting the earth and calculates the vehicle position based on the principle of triangulation. 3D positioning (longitude, latitude, altitude) using 4 satellites for one position measurement, and 2D measuring 2D position (longitude, latitude) using 3 satellites There is positioning. GPS positioning can detect an absolute position, but its accuracy is easily affected by radio wave reception conditions, and accuracy is not always good.

  Therefore, in order to compensate for the respective shortcomings of self-contained navigation and GPS positioning, conventional navigation devices have mainly used a hybrid system that combines self-contained navigation and GPS positioning.

  In Patent Document 1, in a hybrid navigation device, when a vehicle instrument device cannot input a pulse signal corresponding to a vehicle travel distance via a bus, the vehicle instrument device performs An estimated value of the value that was scheduled to be input this time is obtained from the amount of change from the input value, and this estimated value is transmitted to the navigation unit. The navigation unit calculates the current position of the vehicle based on the estimated value.

  Patent Document 2 relates to a vehicle current position detection device, and even if the pulse information from the vehicle speed sensor is somewhat inaccurate, it calculates a moving distance with high accuracy based on the pulse information and improves the current position detection accuracy. The technology is disclosed. Specifically, in the vehicle speed pulse missing period that is likely to occur when the vehicle is at a low speed, the moving distance of the vehicle is estimated based on the distance estimated based on the vehicle travel acceleration before and after the vehicle speed pulse missing period.

JP 2001-124572 A Japanese Patent No. 3449240

  As disclosed in Patent Document 1, a sensor that is set in each part of a vehicle and outputs information on each part of the vehicle and travel information (for example, a distance sensor that outputs a pulse signal corresponding to a travel distance, an engine speed) A rotation sensor that outputs a corresponding pulse signal, a fuel sensor that outputs a remaining amount of fuel, and the like) are connected to the navigation device via an in-vehicle communication bus routed around the vehicle. As a result, the navigation device appropriately acquires data necessary for calculating the position of the vehicle through the in-vehicle communication bus.

  When calculating the vehicle position by the self-contained navigation in the navigation device, the relative movement distance of the vehicle is calculated based on the pulse signal from the distance sensor or the corresponding travel distance information. However, despite the normal operation of the bus communication system, the navigation device may be reset for some reason, such as a power supply voltage drop or a system hang-up. In that case, even if the correct mileage information is acquired by bus communication, the mileage information on the navigation device side is initialized to zero, so the difference between the current mileage information and the previous mileage information is a very large value In other words, there has been a problem that the moving distance becomes an extremely large value, and as a result, the position of the vehicle displayed on the display flies by mistake.

  The present invention solves the above-described conventional problems and provides a vehicle position calculation device and a calculation method thereof that can accurately calculate the vehicle position even when the navigation device is reset during traveling. The purpose is to do.

  The own vehicle position calculation device according to the present invention includes a first generation unit that generates a pulse signal each time the vehicle travels a certain distance, and a pulse signal generated by the first generation unit by integrating the pulse signal. Second generation means for generating travel distance information, and travel distance calculation for receiving the travel distance information generated by the second generation means at a constant cycle and calculating the travel distance of the vehicle based on the difference of the travel distance information Means for determining whether the moving distance is abnormal based on the movement characteristics of the vehicle, and correcting the moving distance calculated by the moving distance calculating means when it is determined that the moving distance is abnormal Correction means.

  Preferably, the own vehicle position calculating device further includes an in-vehicle communication bus, and the travel distance information generated by the second generating means is transmitted to the own vehicle position calculating means via the in-vehicle communication bus. The in-vehicle communication bus may be an external bus, an internal bus, or the like, and the type thereof is not particularly limited. For example, a CAN bus, a MOST bus, or the like is used.

  Furthermore, the own vehicle position calculation device according to the present invention, which can calculate the own vehicle position based on the pulse signal generated each time the vehicle moves a certain distance, receives the pulse signal within a certain period, and calculates the number of pulses between them. The travel distance information generating means for transmitting the travel distance information according to the number of pulses accumulated by counting at a constant cycle, and the relative movement of the host vehicle based on the travel distance information output from the travel distance information generating means Moving distance calculating means for calculating the distance. Preferably, the travel distance information generating unit transmits the travel distance information to the travel distance calculating unit via the in-vehicle communication bus. The travel distance information generating means may include a distance sensor.

  Thus, in calculating the travel distance used for self-contained navigation, the number of pulses of the pulse signal is accumulated instead of the difference of the pulse signal from the distance sensor (difference in the vehicle travel distance information), and the accumulated number of pulses By transmitting the travel distance information according to the above, there is an advantage that even if the travel distance information acquisition by bus communication fails, the correct travel distance can be acquired if succeeded next time.

  Furthermore, the vehicle position calculation method for calculating the vehicle position based on the pulse signal generated according to the travel distance of the vehicle according to the present invention integrates pulse signals, and travel distance information according to the accumulated number of pulses. A first step for generating the vehicle distance, a second step for transmitting the travel distance information at a fixed period, a third step for receiving the travel distance information, and calculating a travel distance of the vehicle based on the difference of the travel distance information. A step for determining whether or not the moving distance is abnormal based on the motion characteristics of the vehicle, and a step for correcting the moving distance calculated in the third step when it is determined that the moving distance is abnormal. And a sixth step of calculating the vehicle position based on the corrected moving distance.

  According to the present invention, when calculating the travel distance of the host vehicle based on the travel distance information received at a constant cycle, it is determined whether the travel distance (or the vehicle position) is abnormal from the motion characteristics of the host vehicle. However, if it is determined to be abnormal, the movement distance is corrected. Therefore, even if the vehicle position calculation device (for example, the navigation device) is reset or initialized for some reason, The vehicle position can be calculated with high accuracy.

  The best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a vehicle position calculation apparatus according to an embodiment of the present invention. The own vehicle position calculation device 1 includes a sensor unit 2 installed in each part of the own vehicle to detect the state of the vehicle, a bus communication control unit 4 connected to the sensor unit 2 via an external bus 3, and a bus communication control unit. 4 and a navigation device 6 connected via an internal bus 5. In addition to the navigation device 6, the internal bus 5 is connected to an instrument display unit 7 incorporated in the front panel of the vehicle, an alarm unit 8 for notifying various alarms, an engine control unit (ECU) 9, and the like.

  The sensor unit 10 includes a distance sensor that outputs a pulse signal each time the host vehicle travels a certain distance, a gyro sensor that detects the direction of the host vehicle, a rotation sensor that outputs a pulse signal corresponding to the engine speed, a fuel It includes a fuel sensor that outputs the remaining amount, a parking sensor that indicates an on / off state of the parking brake, and the like. For example, the distance sensor generates a pulse signal including a plurality of pulse trains each time the tire makes one rotation by attaching a plurality of position sensors to the wheels of the host vehicle at equal intervals. Of the sensor unit 2, the distance sensor and the gyro sensor are used as sensors for calculating the position of the vehicle by self-contained navigation.

  Various signals from the sensor unit 2 are output to the external bus input of the bus communication control unit 4. When the bus communication control unit 4 receives a pulse signal from the distance sensor, the bus communication control unit 4 adds or integrates the received pulse numbers, and transmits travel distance information corresponding to the integrated pulse numbers. That is, instead of outputting a difference in pulse signals (difference in travel distance of the host vehicle), travel distance information corresponding to the count result of the number of pulses is transmitted. The bus communication control unit 4 transmits travel distance information of 16-bit (2 bytes) data, for example, to the internal bus 5 at a constant cycle, for example, 40 ms. The bus communication control unit 4 also performs processing as necessary on signals from other sensors and outputs the signals to the internal bus 5.

  The navigation device 6 receives travel distance information and gyro sensor direction information from the bus communication control unit 4 via the internal bus 5, and calculates the vehicle position based on these information. The instrument display unit 7 receives signals regarding the engine speed and the fuel remaining amount via the internal bus 5 and displays them on instruments. The alarm unit 8 notifies the situation that may interfere with safe driving by voice or the like. The ECU 9 controls optimal engine operation based on the signal from the sensor unit 2.

  FIG. 2 is a diagram showing a configuration of the navigation device 6. As shown in the figure, the navigation device 6 includes a bus interface 10 connected to the internal bus 5, a GPS receiver 12 that receives radio waves from GPS satellites and measures the current position and current direction of the vehicle, and an antenna 14. VICS (Vehicle Information and Communication System) / FM multiplex receiver 16 for receiving current road traffic information outside the vehicle via the vehicle, user input interface 20 including operation panel 22, voice input unit 24 and remote control operation unit 26, large capacity A storage device 30 having a hard disk, a data communication control unit 32 that enables wireless or wired data communication, an audio output unit 40 that outputs audio from a speaker 42, a display control unit 50 that displays an image on a display 52, and a program Program memory 60, data memory for temporarily storing data It contains Li 70 and control unit 80.

  The storage device 30 stores a program and a database for executing various navigation functions. The database includes map data, facility data, and the like, and the map data includes road (link) data and intersection data related to roads. Link data is data related to the road connecting the intersections, node data indicating the longitude and latitude of the start and end points of the road, data indicating the type of road (national road, general road, prefectural road, etc.), width, regulation ( For example, it includes data such as one-way traffic) and the number of lanes.

  The program memory 60 loads a program stored in the storage device 30. For example, a vehicle position calculation program 62 for calculating the vehicle position by self-contained navigation based on travel distance information and direction information from the sensor unit 2 and calculating the vehicle position based on the positioning result of the GPS receiver 12, Is stored on the road (link) of the map data, the vehicle position display program 66 for synthesizing the vehicle position on the road map and displayed on the display, the program 68 for searching the route to the destination, etc. To do. The data memory 70 includes data 72 from the bus communication control unit 4, positioning data 74 measured by the GPS receiver 10, map data 76 corresponding to the vehicle position read from the storage device 30, and route searched. Data 78 and the like are stored. The control unit 80 controls the operation of each unit according to these programs.

  Next, the operation for calculating the vehicle position will be described with reference to the flowchart of FIG. When the ignition of the own vehicle is turned on (step S101), the operation of the sensor unit 2 is started (step S102). At the same time, positioning of the GPS receiver 12 of the navigation device is started.

  As the vehicle travels, the distance sensor outputs a pulse signal including a plurality of pulse trains every time it travels a certain distance. The bus communication control unit 4 processes the received pulse signal, and transmits travel distance information corresponding to the number of pulses accumulated or added at regular intervals (for example, 40 ms) (step S103).

  FIG. 4A is a diagram for explaining the travel distance information. Here, simple numbers are used for easy understanding of the explanation. At time t1, the bus communication control unit 4 adds the number of pulses received this time to the number of pulses accumulated up to the previous time, and transmits the accumulated value “9999” to the internal bus 5 as travel distance information. If the number of pulses received from the distance sensor within a certain period is “1” at time t2, which is the next cycle, the integrated value “10000” is transmitted to the internal bus 5 as travel distance information. If the number of pulses received from the distance sensor within a certain period is “2” at time t3, which is the next cycle, the integrated value “10002” is transmitted, and received at time t4, which is the next cycle. If the number of pulses is “1”, the integrated value “10003” is transmitted to the internal bus 5 as travel distance information.

  The navigation device 6 receives the travel distance information via the bus interface 10 and stores it in the data memory 70. The control unit 80 calculates the travel distance of the own vehicle from the difference between the travel distance information received last time and the travel distance information received this time stored in the data memory 70 (step S104). As shown in FIG. 4A, the control unit 80 of the navigation device 6 receives the current travel distance information at time t2, and calculates a difference from the previous travel distance information. In this example, the difference between “10000” and “9999” is calculated, and the movement distance corresponding to the difference “1” is obtained. Similarly, at time t3, which is the next cycle, the difference between the current travel distance information and the previous travel distance information is similarly obtained, and the travel distance corresponding to the difference is calculated.

  Next, the control unit 80 determines whether or not the motion characteristic of the own vehicle is abnormal based on the calculated travel distance (step S105). For example, the calculated moving distance is extremely large, and in order to realize such movement, it is determined that the vehicle is abnormal when the movement characteristic exceeding the range normally assumed of the own vehicle is required. One of the causes of such an abnormality is when the navigation device is reset or initialized for some reason, such as a power supply voltage drop or a system hang-up. If the navigation device is reset, the mileage information received from the bus communication control unit 4 is initialized, the value becomes “0”, and the difference of the mileage information becomes an abnormally large value. is there.

  For example, as shown in FIG. 4B, it is assumed that the navigation device is reset and restored in a period including time t3. In this case, the bus communication control unit 4 normally transmits the travel distance information at time t3, but the navigation device 6 cannot acquire the travel distance information via the bus interface 10, and thus the current travel The distance information becomes the initialized value “0”. Therefore, when calculating the travel distance at time t4, the difference between the previous travel distance information and the current travel distance information, that is, the difference between “0” and “10003” becomes an abnormally large value, and the travel distance is extremely large. Become bigger. Even if such a large moving distance occurs, no abnormality has occurred on the bus communication side, so it is determined from the movement characteristics of the own vehicle whether or not the moving distance is abnormal.

  On the other hand, if the motion characteristic of the own vehicle is not abnormal, the travel distance calculated from the difference in travel distance information is recognized as a correct value (step S106). When it is determined that the motion characteristic of the host vehicle is abnormal, the control unit 80 corrects the movement distance according to a predetermined method (step S107).

  Next, the control unit 80 synthesizes the calculated travel distance and the direction information vector from the gyro sensor, and adds this to the current position to calculate and update the position of the vehicle by self-contained navigation (step S80). S108).

  Next, a method for determining the motion characteristics of the own vehicle and a method for correcting the movement distance will be described with reference to the flowcharts of FIGS.

(First correction method)
When the control unit 80 receives the current travel distance information from the bus communication control unit 4 (step S201), the control unit 80 obtains a difference between the current travel distance information and the previous travel distance information (step S202), and the difference is the threshold. It is determined whether or not the value is larger (step S203). When greater than a certain threshold, this means an abnormal motion characteristic.

  When there is an abnormality in the motion characteristic, the control unit 80 replaces the current travel distance information with the previous travel distance information (step S204). Taking FIG. 4B as an example, if the threshold value is “100”, the difference at time t4 is “10003”, which is determined to be abnormal. Therefore, as shown in FIG. 4C, the travel distance information of the navigation device at time t3 is replaced with the travel distance information at time t2. As a result, the difference at time t4 becomes “3”, and the movement distance while the navigation device is reset is corrected. When the host vehicle is traveling at a constant speed, the travel distance is corrected almost accurately.

  Note that, at time t3 in FIG. 4B, the difference on the navigation device side is set to “0”. However, if the difference from the previous travel distance information is appropriately calculated even during resetting, The difference between t2 and time t3 is “10000”. In this case as well, since the travel distance information at time t3 is replaced with the travel distance information at time t2, the difference is “0” as a result (FIG. 4 (c)).

  If the difference is less than or equal to the threshold value, the travel distance calculated by the difference between the current travel distance information and the previous travel distance information is recognized as a correct value (step S205). The control unit 80 calculates and updates the vehicle position using the travel distance and the direction information obtained as described above (step S206).

(Second correction method)
When the control unit 80 receives the current travel distance information from the bus communication control unit 4 (step S301), the control unit 80 calculates the travel speed of the host vehicle from the current travel distance information and the previous travel distance information (step S302). It is determined whether or not the traveling speed is greater than a threshold value (step S303). This threshold value sets the maximum speed of the own vehicle, for example. When the traveling speed is higher than the maximum speed (threshold), this means that the movement characteristics of the own vehicle are abnormal. In this case, the control unit 80 replaces the previously calculated movement distance with the current movement distance (step S304). In other words, the difference obtained at the previous time is replaced.

  If the travel speed is less than or equal to the threshold value, the travel distance calculated from the difference between the current travel distance information and the previous travel distance information is recognized as a correct value (step S305). The control unit 80 calculates and updates the vehicle position using the travel distance and the direction information obtained as described above (step S306).

(Third correction method)
When the control unit 80 receives the current travel distance information from the bus communication control unit 4 (step S401), the control unit 80 calculates the acceleration of the vehicle from the current travel speed and the previous travel speed (step S402). It is determined whether or not it is larger than the threshold value (step S303). As this threshold value, for example, an acceleration exceeding the performance limit of the own vehicle is set. When the acceleration is greater than the threshold value, this means that the vehicle's motion characteristics are abnormal. In this case, the control unit 80 calculates the travel distance from the own vehicle speed measured by the current GPS receiver 12, and replaces this with the current travel distance (step S404).

  If the acceleration is equal to or less than the threshold value, the travel distance calculated from the difference between the current travel distance information and the previous travel distance information is recognized as a correct value (step S405). The control unit 80 calculates and updates the vehicle position using the travel distance and the direction information obtained as described above (step S406).

  In the first to third correction methods, different determination criteria for motion characteristics are used, but the combination thereof may be changed as appropriate. For example, in the first correction method, it may be determined whether the traveling speed of the host vehicle is greater than a threshold value or whether the acceleration is greater than a threshold value.

  Furthermore, when the time Tc required for resetting the navigation device is known in advance (for example, the time required for recovery from down is 3 seconds), the time when it is determined that there is an abnormality in the vehicle's motion characteristics Accordingly, the correction of the first to third movement distances may be continued during the period of time Tc described above.

  According to the present embodiment, in the navigation device that calculates the vehicle position by acquiring the accumulated or added travel distance information from the bus communication control unit 4, the navigation device temporarily goes down for some reason, and the travel distance Even if the information cannot be properly processed, the movement distance of the vehicle during that time is appropriately corrected, so that it is possible to prevent the deterioration of the vehicle position accuracy.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible. In the above embodiment, the configuration in which the sensor unit 2 and the bus communication control unit 4 are connected by the external bus 3 is shown. However, the sensor unit 2 includes a circuit that accumulates the number of pulses and transmits the accumulated travel distance information. The travel distance information may be transmitted directly from the sensor unit 2 to the navigation device 6. Alternatively, the bus communication control unit 4 may include a distance sensor. Furthermore, in the above embodiment, the operation for calculating the vehicle position is controlled by a program. However, the present invention is not limited to this, and it may be executed by a hard wafer circuit. Further, the navigation device may be complex with other audio devices and video devices.

  The vehicle position calculation device and calculation method according to the present invention can be used in an electronic device such as a navigation device, a navigation system, or a computer including a navigation function mounted on a vehicle or the like.

It is a block diagram which shows the structure of the own vehicle position calculation apparatus which concerns on the Example of this invention. It is a block diagram which shows the structure of a navigation apparatus. It is a flowchart explaining operation | movement of the own vehicle position calculation apparatus of a present Example. It is a figure explaining the travel distance information which accumulated the pulse number in a bus communication control part. It is an operation | movement flowchart explaining the 1st correction method of a movement distance. It is an operation | movement flowchart explaining the 2nd correction method of a movement distance. It is an operation | movement flowchart explaining the 3rd correction method of a movement distance.

Explanation of symbols

1: Vehicle position calculation device 2: Sensor unit 3: External bus 4: Bus communication control unit 5: Internal bus 6: Navigation device 7: Instrument display unit 8: Alarm unit 9: Engine control unit (ECU) 10: Bus interface 12: GPS receiver 40: Audio output unit 50: Display control unit 52: Display 60: Program memory 70: Data memory 80: Control unit

Claims (8)

A vehicle position calculation device for calculating a vehicle position,
First generation means for generating a pulse signal each time the vehicle travels a certain distance;
Second generation means for generating mileage information of the vehicle by integrating the pulse signals generated by the first generation means;
A navigation device that receives the travel distance information generated by the second generation means,
The navigation device
The travel distance information generated by the second generation means is received at a constant cycle, the received travel distance information is sequentially stored in a memory, and the difference between the previous travel distance information stored in the memory and the current travel distance information Travel distance calculation means for calculating the travel distance of the vehicle based on
Correction means for correcting the movement distance calculated by the movement distance calculation means ,
The correction means replaces the current travel distance information stored in the memory with the previous travel distance information before being reset when the navigation device is reset,
Self-vehicle position calculation device. The own vehicle position calculation device further includes an in-vehicle communication bus, and the travel distance information generated by the second generation means is transmitted to the travel distance calculation means of the navigation device via the in-vehicle communication bus. The host vehicle position calculation device according to 1. The own vehicle position calculation device according to claim 1, wherein the correction unit is continued for a period required until the navigation device is recovered from a down state. The own vehicle position calculation device according to any one of claims 1 to 3 , further comprising own vehicle position calculation means for calculating the own vehicle position based on the calculated moving distance and direction information of the own vehicle. Calculation device. A vehicle position calculation device capable of calculating the vehicle position based on a pulse signal generated each time the vehicle moves a certain distance,
Travel distance information generating means for receiving a pulse signal within a certain period and transmitting the travel distance information according to the number of pulses accumulated by counting the number of pulses between them at a constant period;
A bus for transmitting the travel distance information output from the travel distance information generating means;
A navigation device that receives mileage information output from the bus,
The navigation device
A bus interface that receives the travel distance information generated by the travel distance information generating means at a constant period;
A memory for sequentially storing mileage information received from the bus interface;
Travel distance calculation means for calculating the travel distance of the vehicle based on the difference between the previous travel distance information stored in the memory and the current travel distance information;
Correction means for correcting the movement distance calculated by the movement distance calculation means,
The correction means replaces the current travel distance information stored in the memory with the previous travel distance information before being reset when the navigation device is reset,
Self-vehicle position calculation device. 6. The own vehicle position calculation device according to claim 5 , wherein the travel distance information generating means includes a distance sensor that outputs a pulse signal each time the vehicle moves a certain distance. A vehicle position calculation method for calculating a vehicle position based on a pulse signal generated according to a travel distance of the vehicle,
Integrates the pulse signal, the answering step to generate a travel distance information corresponding to the number of accumulated pulses,
And Luz step to transmit the travel distance information in a certain period,
Receiving mileage information in the navigation device;
Sequentially storing received mileage information in a memory;
And Luz step to calculate the movement distance of the vehicle based on the difference between the previous travel distance information stored in the memory and the current travel distance information,
The calculated movement distance and a Luz step be corrected,
In the correcting step, when the navigation device is reset, the current travel distance information stored in the memory is replaced with the previous travel distance information before being reset.
The vehicle position calculation method. The vehicle position calculation method according to claim 7, wherein the correcting step is continued for a period required until the navigation apparatus is recovered from being down .

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