JP4593341B2 - Navigation system, control method thereof, and control program - Google Patents

Description

  According to the present invention, in the navigation technology, the vehicle ECU can be used even when GPS satellite radio waves are insufficient by using the reference data of the cumulative value of the acceleration value obtained from the acceleration sensor and the vehicle speed obtained from the change amount of the position data by GPS. The vehicle speed is estimated with high accuracy without wiring connection or a vehicle speed signal.

  In recent years, with the progress of information processing technology such as GPS, the spread of navigation systems is remarkable. The navigation system displays the position and orientation of the vehicle on the surrounding map, calculates the route to the specified destination, and outputs guidance guidance along the route on a screen or synthesized voice. .

Many navigation systems have a mechanism for capturing GPS, gyro, and vehicle speed signals into the system main body (that is, main body unit) in order to grasp the position and traveling state of the vehicle that change every moment. Among these, the vehicle speed signal is a voltage pulse corresponding to a change in the speed of the vehicle (vehicle), and is output from the vehicle ECU (so-called engine control unit). For example, Patent Document 1 shows an example in which the moving speed of a vehicle is detected by a vehicle speed sensor.
Japanese Patent Laid-Open No. 5-26681

  When the main unit of the car navigation system as described above is installed in the vehicle, it is necessary to perform wiring with the main body device in order to capture the vehicle speed signal output from the vehicle ECU into the system. However, since the installation position of the vehicle ECU differs depending on the vehicle type, wiring work corresponding to the vehicle type is separately required, which causes a problem of increasing the time and cost required for installation.

  In addition, the portable type car navigation system has a specification in which a vehicle speed signal is not taken into the system body so that the vehicle can be easily attached to and detached from the vehicle. For this reason, the vehicle position calculation calculation depends only on the data obtained from the GPS and the gyro, and there is a problem that the accuracy of the vehicle position is remarkably deteriorated in an environment where GPS radio waves cannot be received.

  The present invention solves the above-described problems of the prior art, and its purpose is to calculate the cumulative value of acceleration values obtained from an acceleration sensor and the vehicle speed obtained from the amount of change in position data by GPS in navigation technology. By using the reference data, even when GPS satellite radio waves are insufficient, the vehicle speed is estimated with high accuracy without wiring connection with the vehicle ECU or a vehicle speed signal.

  In order to achieve the above object, according to one aspect of the present invention (Claims 1, 4, and 7), a navigation sensor unit including a GPS, an information storage unit and an input / output unit, and information processing using each unit are performed. In a navigation system (a control method and a control program) mounted on a vehicle, the control unit acquires an acceleration value or a value corresponding to the acceleration as an acceleration value, and the acceleration value is Corresponding combinations of accumulating means (process) for calculating the accumulated value, vehicle speed calculating means (process) for calculating the vehicle speed based on the amount of change in position obtained by GPS, and each set of the accumulated value and the vehicle speed at the same time point In addition, the recording means (processing) for recording in the storage unit as control data, and when the satellite radio wave reception state in the GPS is insufficient, based on the cumulative value at the present time, the control The speed associated with reference to over data to the same accumulation value or close the accumulated value, characterized in that it realizes estimation process for estimating the vehicle speed at the present time (the unit), the.

  In this way, by using the reference data of the accumulated acceleration value obtained from the acceleration sensor and the vehicle speed obtained from the change amount of the position data by GPS, even when the GPS satellite radio wave is insufficient, the wiring connection with the vehicle ECU It becomes possible to estimate the vehicle speed with high accuracy without a vehicle speed signal.

  According to another aspect of the present invention (Claims 2, 5, and 8), in each of the above aspects, the recording means (process) uses the set as the reference data for each predetermined increment of the vehicle speed or the cumulative value. It is characterized by incorporating and recording.

  In this way, by recording the reference data for each predetermined increment of the vehicle speed and cumulative value, the cumulative value and the vehicle speed value do not jump irregularly compared to the case of recording at a constant time period, etc. Good estimation accuracy can be realized regardless of the range.

  According to another aspect of the present invention (Claims 3, 6 and 9), in each of the above aspects, the recording means (process) is a new one corresponding to the same cumulative value as the cumulative value already recorded in the control data together with the vehicle speed. When the vehicle speed is detected again, the average value of the already recorded vehicle speed and the new vehicle speed is recorded in association with the accumulated value.

  In this way, even when there is a vehicle speed calculated and recorded at a certain time corresponding to the same cumulative value, the vehicle speed calculated and recorded at another time is averaged and replaced and updated, so that Errors due to load conditions of passengers, slopes, curves, etc. are canceled out, and the accuracy of vehicle speed estimation is improved.

  As described above, according to the present invention, in the navigation technology, the GPS satellite radio wave is not detected by using the reference data of the accumulated acceleration value obtained from the acceleration sensor and the vehicle speed obtained from the change amount of the position data by GPS. Even if it is sufficient, it becomes possible to estimate the vehicle speed with high accuracy without wiring connection with the vehicle ECU or without a vehicle speed signal.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. Note that the assumptions common to the explanation in the background art and the problems are not repeated.

[1. Constitution〕
The present embodiment relates to a navigation system (hereinafter referred to as “the present system”) mounted on a vehicle, but can also be grasped as a control method or a control program. First, FIG. 1 shows an example of components of the present system.

  That is, 1 is a main CPU that is a control unit of the entire system, and is a part that performs information processing using other units. In addition, the type and configuration of the information storage unit are arbitrary. As an example, in addition to the main storage unit 2 such as SRAM, SDRAM, and FLASH ROM including a system calculation area and a program storage area, a hard disk as an external storage device By providing the recording medium unit 5 using a writable / readable medium such as the above, a storage unit as a whole is configured, and the main storage unit 2 and the storage media unit 5 are appropriately set according to the type and algorithm of information to be stored. Use properly. On the storage media unit 5, control data D, which is a database, is recorded.

  Reference numeral 3 denotes a display control unit such as a graphic chip for performing drawing control of maps and menus, and 4 denotes a CPU peripheral circuit unit such as each device I / F (interface) or chip set. As the navigation sensor unit, there are a relative direction detection unit 6 using a gyro sensor, an absolute position detection unit 7 using GPS, and an acceleration detection unit 8 using an acceleration sensor.

  Reference numeral 9 denotes a vehicle I / F unit that captures a back signal, a parking brake signal, an illumination signal, and the like. Of the information input / output unit, the output part includes a video signal processing unit 10 that processes a video signal, and a screen display unit such as a liquid crystal display panel that actually displays a map, a menu, and the like using the video signal. There are eleven.

  FIG. 1 shows a main unit composed of a main unit and a display unit in the navigation system. As an information input unit, although not shown, an operation connected to the main unit by a signal line or the like is shown. There are switch panels and remote control units.

  Moreover, in this system, each part 11-14 corresponding to the following functional actions is implement | achieved and performed by main CPU1 which is a control part according to a predetermined control program. That is, the accumulating unit 11 (accumulating means) acquires a vehicle acceleration or a value corresponding to the acceleration as an acceleration value, and calculates a cumulative value obtained by accumulating the acceleration value (accumulating process). Moreover, the vehicle speed calculation part 12 (vehicle speed calculation means) calculates a vehicle speed based on the amount of change in position obtained by GPS (vehicle speed calculation process). Further, the recording unit 13 (recording unit) records each set of the accumulated value and the vehicle speed at the same time in association with each other and records it as the reference data D (database) in the storage media unit 5 (recording process). Then, the estimation processing unit 14 (estimation processing means) refers to the reference data D based on the cumulative value at the present time when the satellite radio wave reception state at the GPS is insufficient, and the cumulative value or the close cumulative value. The current vehicle speed is estimated based on the vehicle speed associated with the value (estimation process).

[2. Principle of operation)
The specific principle of these operations is as follows. First, in a state where GPS information (satellite radio waves) can be received, the vehicle speed calculated based on the received GPS information (amount of change in the current position in unit time) is used for grasping the position of the host vehicle and detecting the running state. When the GPS information cannot be received, the vehicle speed is estimated using the accumulated value of the acceleration sensor output and the reference data D (FIG. 5).

  The acceleration sensor of the acceleration detector 8 outputs a voltage value corresponding to the acceleration, and the accumulated value of the acceleration output is the accumulated value of the voltage value. Of course, when using an acceleration sensor that outputs the acceleration itself, it goes without saying that the numerical value may be used as it is. These voltage values and acceleration itself are collectively referred to as acceleration values.

  Taking a general voltage value as an example of such an acceleration value, a positive voltage value is output when the voltage value changes in the acceleration direction (the direction in which the speed increases). When the speed changes in the deceleration direction (the direction in which the speed decreases), a negative voltage value is output. That is, when the voltage value corresponding to this acceleration is accumulated from the time when the vehicle is shifted from the stopped state to the moving state, the accumulated value is 0 (zero) when the vehicle is again stopped. Will be.

  In this case, the cumulative value of acceleration values such as voltage values and the vehicle speed at that time calculated from the GPS information are stored in the reference data D in association with each predetermined time. If the information cannot be received or can be received, but the received information is small and the vehicle speed cannot be calculated, the cumulative value of the acceleration value is calculated based on the acceleration sensor output, and the vehicle speed corresponding to the cumulative value is calculated. By reading from the reference data D (FIG. 5), it becomes possible to estimate the vehicle speed even in a tunnel where GPS information cannot be received, and more accurate position detection can be performed.

[3. (Specific action)
In this system, the acceleration sensor output and GPS position data are used to calculate the traveling speed (vehicle speed) of the vehicle, but the operation for that purpose is as shown in the flowchart of FIG. Depending on whether or not the vehicle position can be recognized using GPS (step 30), it can be divided into the following two modes.

  When GPS can be used, the database creation mode (hereinafter also referred to simply as “creation mode”) is entered (step 31), and not only the acceleration sensor output but also the absolute position coordinates, which are GPS position data, are taken in every unit time and stored in the storage unit. can do. Based on this, the vehicle speed is obtained from the amount of change per hour in the GPS position data (step 32), and used for the calculation of the vehicle position together with the GPS and gyro output (step 33).

  In the creation mode, the vehicle speed obtained based on the GPS is stored in the storage media unit 5 together with the accumulated acceleration value output from the acceleration detecting unit 8, and the vehicle speed and accumulated value are stored in a database. This will be described later with reference to FIG. This creation mode operates whenever the GPS radio wave is received, and the reference data D, which is a database, is updated so as to have higher accuracy.

  When the GPS cannot be used, the database utilization mode (hereinafter also referred to as “utilization mode”) is set (step 41), and the vehicle speed is stored in the storage medium 5 based on the accumulated acceleration value since the vehicle started traveling. The database is checked and determined based on the vehicle speed recorded corresponding to the accumulated value (step 42), which will be described later with reference to FIG. Then, the determined vehicle speed is used for the own vehicle position calculation (step 43). In this way, the vehicle speed can be estimated even in a state where position data from GPS cannot be received.

  In any mode, the display of the vehicle position is updated based on the result of the vehicle position calculation calculation or the like (steps 34 and 44). Each mode will be described in detail below.

[3-1. (Create mode)
In the creation mode, as illustrated in the flowchart of FIG. 3, for each unit time, an absolute position detected by the GPS by the absolute position detection unit 7 and an acceleration value that is an acceleration output detected by the acceleration detection unit 8 are obtained. The CPU 1 monitors (step 11), and the state where there is no change is regarded as the “vehicle stop state” (step 12). That is, the time point at which a change in the absolute position and acceleration value is detected is regarded as “start of vehicle travel” (step 12), and the absolute position and acceleration value are stored for each unit time thereafter (step 11). (Step 13).

  In the CPU 1, among these data, for the absolute position data, the vehicle speed calculation unit 12 calculates the vehicle speed from the position change (movement distance) per unit time (step 14), and the recording unit 13 stores the calculation result. The data is stored in the storage media unit 5 every unit time (step 16). The calculated vehicle speed is applied to the vehicle position calculation as shown in Step 33 of FIG. 2 (Step 15).

  Further, the acceleration value is an acceleration sensor output per unit time, and the accumulating unit 11 obtains an accumulated value that is data corresponding to a change in vehicle speed by accumulating this value (step 14). The recording unit 13 stores the accumulated value of the data for each time as reference data D in the storage media unit 5 in a form synchronized with the position data (step 16), and retains the accumulated acceleration value at the head of the loop (step 11). (Step 17).

  Here, Table 1 shown in FIG. 4 shows the specific contents of the calculation of the vehicle speed and the cumulative acceleration, that is, the cumulative value. As a result, the data of the speed V and the cumulative value Σα are transferred to the storage media unit 5. It is stored as control data D which is a database. An example of the concept is shown in Table 2 of FIG. By using this database, the vehicle speed V can be determined from the cumulative value Σα.

[3-2. Database utilization mode)
In the utilization mode, the speed V is determined from the cumulative value Σα as described above. For this reason, a database as shown in Table 2 shown in FIG. This database is used to determine the vehicle speed by comparing the accumulated acceleration value and the database when position information from the GPS cannot be received.

  In the utilization mode, the acceleration value that is the output of the acceleration detection unit 8 is accumulated every unit time after the vehicle starts running (Σα), and the value closest to the accumulated Σα is stored in the storage media unit 5. A search is made from the database (control data D), the speed V at the time of the corresponding Σα is determined as the vehicle speed, and used for the calculation of the vehicle position.

  Specifically, as shown in the flowchart of FIG. 6, when an acceleration value obtained per unit time (step 21), that is, when an acceleration occurs (step 22), the acceleration value is taken into the storage unit 2 (step 22). 23) The accumulating unit 11 calculates the accumulated value (step 24). Then, the estimation processing unit 14 compares the accumulated value with the reference data D, which is a database in the storage media unit 5 (step 25), searches for the vehicle speed corresponding to the accumulated value (step 26), and uses this as the vehicle position. The calculation is applied (step 27), and the process returns to the beginning of the loop (step 21) while maintaining the accumulated acceleration value (step 28).

  If the cumulative value Σα is not identical to the cumulative value Σα in the control data D, the weighted average corresponding to the ratio of the divergence width with respect to the cumulative value based on the vehicle speeds corresponding to the cumulative values before and after the cumulative value Σα. The vehicle speed is calculated by linear correction by calculation.

[4. effect〕
As described above, in the present embodiment, GPS satellites such as tunnels, shadows of buildings and large trees are used by using the reference data of the cumulative value of acceleration values obtained from the acceleration sensor and the vehicle speed obtained from the amount of change in position data by GPS. Even when the radio wave is insufficient, the vehicle speed can be estimated with high accuracy without wiring connection with the vehicle ECU or without a vehicle speed signal. This also reduces the man-hours and costs in wiring work when the navigation system is attached to the vehicle, and the recognition accuracy of the vehicle speed and the vehicle position is improved even in a portable navigation system.

[5. Other embodiments]
In addition, this invention is not limited to the said embodiment, The thing illustrated below and other embodiment other than that are included. For example, in the above-described embodiment, an example in which the accumulated value of the acceleration value that is the acceleration sensor output and the vehicle speed by the GPS is detected at “every predetermined time” to create a database is shown. If the value of the value fluctuates irregularly, the accuracy may vary depending on the range of the value even if linear correction or the like is performed, and it may be difficult to use for subsequent processing.

Therefore, it is desirable that the vehicle speed at that time is acquired and stored in a database every time the accumulated value is set in advance at a predetermined interval. In this case, the recording unit 13 records the set by incorporating the set into the control data D at every predetermined increment of the vehicle speed or the accumulated value. For example, as an example where the cumulative value is fixed at a predetermined interval,

Cumulative value V
Σα (v) (km / h)
1 V1
2 V2
3 V3
4 V4
5 V5
::

However, the speed side may be fixed at a predetermined interval (for example, 5 km / h, 10 km / h, 15 km / h, 20 km / h...).

  As described above, it is not essential to record the reference data for each predetermined increment of the vehicle speed and the accumulated value, but this makes the accumulated value and the vehicle speed value irregular as compared with the case of recording at a constant time period. Therefore, good estimation accuracy can be realized regardless of the range of values.

  Furthermore, in order to improve the estimation accuracy of the vehicle speed, when the “vehicle speed” with respect to the “accumulated value” that has already been stored is detected again, the average value thereof may be stored. In this case, when the vehicle speed calculation unit 12 detects again a new vehicle speed corresponding to the same accumulated value as the already recorded value together with the vehicle speed in the control data D, the recording unit 13 determines the already recorded vehicle speed and the new vehicle speed. Is recorded in association with the accumulated value.

  Thus, even if there is a vehicle speed calculated and recorded at a certain time corresponding to the same cumulative value, it is not essential to replace and update the vehicle speed calculated and recorded at another time and average. As a result, errors due to the load state of the passengers at each time point, slopes, curves, etc. are canceled out, and the estimation accuracy of the vehicle speed is improved.

The functional block diagram which shows the structure of embodiment of this invention. The flowchart which shows the whole process sequence in embodiment of this invention. The flowchart which shows the process sequence in the creation mode in embodiment of this invention. The table | surface which shows the calculation content of the vehicle speed and cumulative acceleration in embodiment of this invention. The figure which shows an example of the database (control data) in embodiment of this invention. The flowchart which shows the process sequence in the utilization mode in embodiment of this invention.

Explanation of symbols

1 ... Main CPU
2 ... main storage unit 3 ... display control unit 4 ... CPU peripheral circuit unit 5 ... storage media unit D ... control data 6 ... relative orientation detection unit 7 ... absolute position detection unit 8 ... acceleration detection unit 9 ... vehicle interface unit 10 ... video Signal processing unit 11 ... screen display unit

Claims (9)

In a navigation system that includes a navigation sensor unit including a GPS, an information storage unit and an input / output unit, and a control unit that performs information processing using each unit, and is mounted on a vehicle,
By the control unit,
Accumulating means for obtaining a vehicle acceleration or a value corresponding to the acceleration as an acceleration value and calculating a cumulative value obtained by accumulating the acceleration value;
Vehicle speed calculating means for calculating a vehicle speed based on a change in position obtained by GPS;
Recording means for associating and recording each set of the accumulated value and the vehicle speed at the same time in the storage unit;
When the satellite radio wave reception state in the GPS is insufficient, the current vehicle speed is determined by referring to the reference data and the vehicle speed associated with the same cumulative value or a close cumulative value based on the cumulative value at the current time. An estimation processing means for estimating;
The navigation system characterized by realizing. The navigation system according to claim 1, wherein the recording unit records the set by incorporating the set into the reference data at predetermined intervals of the vehicle speed or the accumulated value. The recording means includes
When a new vehicle speed corresponding to the same cumulative value as the cumulative value already recorded with the vehicle speed is detected again in the control data, the average value of the already recorded vehicle speed and the new vehicle speed is associated with the cumulative value. The navigation system according to claim 1, wherein the navigation system is recorded. In a control method for a navigation system mounted on a vehicle, comprising a navigation sensor unit including a GPS, a storage unit and an input / output unit for information, and a control unit that performs information processing using each unit,
By the control unit,
Accumulating processing for obtaining a vehicle acceleration or a value corresponding to the acceleration as an acceleration value and calculating a cumulative value obtained by accumulating the acceleration value;
A vehicle speed calculation process for calculating a vehicle speed based on a change in position obtained by GPS;
A recording process in which each set of the accumulated value and the vehicle speed at the same time is associated with each other and recorded in the storage unit as reference data;
When the satellite radio wave reception state in the GPS is insufficient, the current vehicle speed is determined based on the vehicle speed associated with the same cumulative value or a close cumulative value with reference to the reference data based on the cumulative value at the current time. An estimation process to estimate;
A control method for a navigation system, characterized in that 5. The navigation system control method according to claim 4, wherein the recording process includes recording the set by incorporating the set into the reference data at predetermined intervals of the vehicle speed or the accumulated value. The recording process includes
When a new vehicle speed corresponding to the same cumulative value as the cumulative value already recorded with the vehicle speed is detected again in the control data, the average value of the already recorded vehicle speed and the new vehicle speed is associated with the cumulative value. 6. The navigation system control method according to claim 4, wherein recording is performed. In a control program for a navigation system mounted on a vehicle, comprising a navigation sensor unit including a GPS, an information storage unit and an input / output unit, and a control unit that performs information processing using each of the units,
By the control unit,
Accumulating processing for obtaining a vehicle acceleration or a value corresponding to the acceleration as an acceleration value and calculating a cumulative value obtained by accumulating the acceleration value;
A vehicle speed calculation process for calculating a vehicle speed based on a change in position obtained by GPS;
A recording process in which each set of the accumulated value and the vehicle speed at the same time is associated with each other and recorded in the storage unit as reference data;
When the satellite radio wave reception state in the GPS is insufficient, the current vehicle speed is determined based on the vehicle speed associated with the same cumulative value or a close cumulative value with reference to the reference data based on the cumulative value at the current time. An estimation process to estimate;
A navigation system control program characterized in that The navigation system control program according to claim 7, wherein the recording process records the set by incorporating the set in the reference data at predetermined intervals of the vehicle speed or the accumulated value. The recording process includes
When a new vehicle speed corresponding to the same cumulative value as the cumulative value already recorded with the vehicle speed is detected again in the control data, the average value of the already recorded vehicle speed and the new vehicle speed is associated with the cumulative value. 9. The navigation system control program according to claim 7 or 8, wherein the program is recorded.

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