JPH03154820A - Vehicle position detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vehicle position detection device, and more specifically, it uses an absolute orientation sensor (e.g. geomagnetic sensor, GPS) and also detects the moving direction of the vehicle. The vehicle's orientation is determined using a relative orientation sensor (for example, a wheel speed sensor, a steering angle sensor, or an angular velocity sensor (rate sensor) such as an optical fiber gyro, vibration gyro, or gas rate gyro). The present invention relates to a vehicle position detection device that detects the current position of the vehicle by detecting the current position of the vehicle and combining it with travel distance data obtained from a distance sensor (for example, a wheel speed sensor or a vehicle speed sensor).

<Conventional technology> Conventionally, methods for detecting the position of a vehicle traveling at any point on a road transportation network include a distance sensor, one direction sensor (absolute direction sensor or relative direction sensor), and both methods. It is equipped with a processing device that performs the necessary processing on the output signal from the sensor, and is equipped with a processing device that performs the necessary processing on the output signal from the sensor.
Dead Reckoning (Dead Reckoning) has been proposed in which current position data of a vehicle is obtained while integrating J1 and azimuth θ.

This method calculates, for example, the east-west component ΔX (-ΔjXcosθ) and the north-south component Δy (-ΔjXs1nθ) of Δ based on Δ and θ, and By adding the above components ΔX and Δy, the current position data (Px, Py)
However, the disadvantage is that the errors that the distance sensor and direction sensor inevitably have accumulate as the vehicle continues to travel, and the errors included in the current position data obtained are accumulated. .

Therefore, a vehicle position detection device is being considered that uses two azimuth sensors, a relative azimuth sensor and a geomagnetic sensor that detects the earth's magnetism and determines the absolute azimuth of the vehicle. For example, the mobile object orientation detection device disclosed in Japanese Patent Application Laid-Open No. 60-122311 usually uses a geomagnetic sensor, and the variation of the geomagnetic sensor within a specified time is equal to or greater than a set value, and the variation of the angular velocity sensor is When the minute is less than the set value, the data from the angular velocity sensor is used. Also, ■ Jitsukai 81-19
The vehicle azimuth detection device disclosed in Japanese Patent No. 714 uses only steering angle data multiplied by a predetermined coefficient when the azimuth difference between geomagnetic data and steering angle data is greater than or equal to a predetermined value.

<Problem to be Solved by the Invention> However, in the above item (■), when the geomagnetic sensor data is excluded, position detection continues relying only on the angular velocity sensor data, but if the geomagnetic sensor data is excluded for too long, Due to the cumulative error of the angular velocity sensor, there is a problem in that accurate position detection cannot be continued.

Furthermore, in the case of (2) above, if the removal of the geomagnetic sensor data continues for too long, the azimuth error will accumulate due to the use of only the steering angle sensor data, resulting in a problem that the position detection error will increase.

To explain these problems in detail, when a vehicle passes through a strong magnetic field area such as a railroad crossing or passes through a soundproof wall on a highway,
Although the reliability of geomagnetic sensor data temporarily decreases, the decrease in reliability of geomagnetic sensors does not continue forever;
It is thought that the reliability of geomagnetic sensor data will eventually recover. In such a case, even though the reliability of the geomagnetic sensor sub i has been restored, it is dangerous to rely only on the relative azimuth sensor, and in this case, errors accumulate and the accuracy of detecting the position of the vehicle decreases.

Furthermore, in any of the above cases, there is a problem that if an error inherent in the relative orientation sensor occurs, geomagnetic sensor data will continue to be excluded even if the geomagnetic sensor is normal. In this case as well, since only the relative orientation sensor is relied upon, errors accumulate and the accuracy of vehicle position detection decreases.

The present invention is applicable when a data mismatch occurs as a result of comparison with relative orientation data, and the state in which the absolute orientation sensor data is not used and the relative orientation sensor is used continues for a certain distance or time. Another object of the present invention is to provide a vehicle position detection device that can reuse absolute orientation sensor data.

<Means for Solving the Problems> In order to achieve the above object, the vehicle position detection device of the present invention includes a first method for determining whether the absolute orientation data has been excluded for a certain traveling distance or a certain traveling time. a determination means; a second determination means for determining reliability of the absolute orientation data; and a determination by the first determination means that the exclusion state of the absolute orientation data continues for a certain traveling distance or a certain traveling time, and When the second determination means determines that the absolute azimuth data is reliable, the control means resets the azimuth of the vehicle at that time and replaces it with the azimuth of the vehicle determined from the absolute azimuth data.

According to the vehicle position detection device configured as described above, due to an abnormality in the absolute orientation data or a mismatch between the absolute orientation data and the relative orientation data, the vehicle position detection device uses only the relative orientation data without using the absolute orientation data. When the state in which the azimuth is sought continues for a certain distance or a certain distance, the reliability of the absolute azimuth data is determined, and if it is determined to be reliable, the absolute azimuth data is used. That is, the obtained vehicle direction data is reset using absolute direction data.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 2 is a block diagram showing an embodiment of the vehicle position detection device of the present invention, which includes: -Wheel speed sensor 11 that detects the rotation speed of both left and right wheels (combined as a distance sensor and a relative orientation sensor) , ・Geomagnetic sensor 12, ・Road map memory 2 storing road map data, ・Calculates the estimated position of the vehicle based on data detected by the wheel speed sensor 11 and the geomagnetic sensor 12, and also calculates the estimated position data of the vehicle. It consists of a locator 1 stored in a buffer memory 3, a navigation controller 5 that displays the read vehicle current position on a display 7 superimposed on a map, and interfaces with a keyboard 8.

To explain in more detail, the locator 1 is, for example,
The number of rotations of the left and right wheels is obtained by counting the number of output pulse signals from the wheel speed sensor 11 with a counter, and the count data output from the counter is multiplied by a predetermined value indicating the distance per count. The mileage data per unit time is calculated by multiplying by a constant, and the relative change in direction is determined based on the difference in the number of pulses between the left and right wheels. From this and the absolute direction data of the geomagnetic sensor 12, the vehicle direction is calculated. It calculates data. Note that instead of the wheel speed sensor 11, an optical fiber gyro 13 that reads rotational angular velocity as a phase change of interference light, or a vibrating gyro 14 that detects angular velocity using cantilever vibration technology of a piezoelectric element, etc. may be used. It may be something. However, in these cases, a separate vehicle speed sensor 15 is required as a distance sensor.

The road map memory 2 stores road map data covering a predetermined range in advance, and includes a semiconductor memory,
Cassette tape, CD-ROM.

IC memory, DAT, etc. can be used.

The display 7 uses a CRT, liquid crystal display, or the like to display a road map and the vehicle position while the vehicle is traveling.

The navigation controller 5 is composed of a graphic processing processor, an image processing memory, etc., and performs map searching, scale switching, scrolling, etc. on the display 7.
The current position of the vehicle is displayed.

A procedure for detecting a vehicle position using the apparatus configured as described above will be explained. While the vehicle is running, the position of the vehicle is displayed on the display 7 along with a map based on the sensor data captured by the locator 1. Even during this display, data from each sensor is captured by interrupts at regular intervals. I am trying to update the vehicle location. FIG. 1 shows the vehicle position detection flow at the time of this interruption. Note that this interruption may be performed every fixed distance traveled, which is determined based on vehicle distance data. The value of the above-mentioned fixed time or fixed travel distance (hereinafter referred to as "period" in either case) is appropriately set depending on the type of relative orientation sensor used, the performance of the absolute orientation sensor, etc.

First, in step (2), variations in the time-series output data of the geomagnetic sensor 12 in the above period are detected, and in step (2), abnormality/normality of the geomagnetic sensor 12 is checked based on the number of times the data exceeds a threshold value. If normal, perform a relative check with the relative orientation sensor. That is, the azimuth data θH of the geomagnetic sensor 12 and the relative azimuth sensor 11.
13 or 14 (Step ■, θ, -1 is the estimated bearing value of the previous cycle), if they match (Step ■), the vehicle's direction data is calculated based on both data. Calculate the direction (step ■). This calculation is performed by assigning a predetermined weight to both data and taking the average value.

Furthermore, the counters and counters C are reset (step 2, the counters and counters C are used in the procedure following step 2). Then, the estimated position of the vehicle in the current cycle is determined from the vehicle orientation data determined by the above method and the travel distance data (step (2)). Of course, at this time, a map matching method may be adopted in which the estimated position of the vehicle is corrected by comparing it with the road map data, evaluating the degree of correlation with the road map data, and setting the current position of the vehicle on the road. (See Publication No. 63-148115).

If a NO determination is made in step (2) or step (2), the procedure starts from step (2). First, step ■
Now, it is assumed that the azimuth data of the geomagnetic sensor 12 is not used, and the counter k is incremented by 1 in step (2). In step [share], it is determined whether the geomagnetic sensor 12 is currently correcting the amount of magnetization. Magnetization amount correction processing is performed when the geomagnetic sensor 12 is affected by vehicle body magnetization (judgment as to whether it is affected by vehicle body magnetization can be made, for example, by detecting an abnormality in geomagnetic sensor data or at a railroad crossing by map matching processing). This is a process that is automatically performed to offset the influence of vehicle body magnetization (based on passing detection, etc.), and the procedure is described, for example, in Japanese Patent Application Laid-Open No. 1-98.
It is detailed in the No. 920 publication. If it is determined that the amount of magnetization is being corrected in step [phase], the process moves to step [phase].
The estimated orientation value θt-1 of the previous cycle and the relative orientation sensor 11.
The current direction is determined from the turning data Δθ of No. 13 or 14 (θ, −1+jtθdt). That is, the data of the geomagnetic sensor 12 is not used at all, and the direction is estimated based only on the data of the relative direction sensor 11, 13, or 14.

If the amount of magnetization is not being corrected, proceed to step (3) and check the value of the counter. If it is less than the predetermined value ko, the process moves to step [stock]. In other words, the counter k is the predetermined value ko
The direction estimation based only on the data from the relative direction sensor 11, 13 or 14 continues until the point is reached. This predetermined value ko is set to a number of times such that even if the direction detection is repeated based only on the data of the relative direction sensor 11, 13, or 14, the error will not accumulate to a large extent. In other words, if the predetermined value kO is set to a very large value, the direction estimation based only on the data of the relative direction sensor 11.13 or 14 will be repeated many times, and the direction error will accumulate and the vehicle position detection will be affected. Since this may have an adverse effect, the predetermined value kO is suppressed to an appropriate value to prevent the influence of the accumulation of orientation errors from appearing. In step 0, the reliability of the geomagnetic sensor data is determined. The reliability of geomagnetic sensor data is considered to be restored in the following cases. for example,(
1) Assuming that the magnetization amount correction process of the geomagnetic sensor 12 has been completed, the variation in the magnitude (absolute value) of the geomagnetic sensor data measured from the center of the azimuth circle is the radius of the azimuth circle of the geomagnetic sensor in a normal state. When the dispersion of the geomagnetic sensor data falls within the predetermined range when running in a straight line, (3) The logical product of (1) and (2) above, (4) When turning right or left at an intersection, when driving on a curve with a turning angle greater than a certain value, when the angular increment measured by the relative orientation sensor before and after driving the curve almost matches the angular increment determined by the geomagnetic sensor data, etc. If any of (1) to (4) is satisfied, it is assumed that the reliability of the geomagnetic sensor data has been restored in step (2), and the process proceeds to step [Yes].

If reliability has not been restored, execute the procedure in step [phase]. In addition, if all of (1) to [4] are satisfied in step @, it may be determined that there is reliability,
You may select any three, two, or one of the four items (1) to (4) and make a judgment based only on that three, two, or one item.

In steps [Yes] to [Yes], the recovered geomagnetic sensor data is taken in. In this embodiment, the geomagnetic sensor data to be imported is limited to data obtained when the vehicle is traveling on a straight road. This is because when driving on a straight road, the geomagnetic sensor data takes a substantially constant value, so accurate geomagnetic sensor data can be obtained by a simple process of taking an average. Note that it is sufficient to determine whether the vehicle is traveling on a straight road in a relatively short period of time, and the output data of the relative orientation sensor 11, 13 or 14 can be used to determine whether the vehicle is traveling on a straight road or not. If the vehicle is not currently traveling in a straight line, set C-0 in step (2) and execute the procedure in step [phase]. If the vehicle is traveling in a straight line, the counter C is incremented by 1 in step (2), and it is checked in step (2) whether the counter C has reached a predetermined value Co. This predetermined value Co is set to a value that allows the vehicle to continue traveling in a straight line and collect a sufficient number of data to average the geomagnetic sensor data.

As long as the counter C does not reach the predetermined value Co, the procedure of step [phase] is continued. When the counter C reaches a predetermined value Co, the geomagnetic sensor data is averaged in step (2), and this average value is calculated at the current (current cycle) in step [Yes].
The direction of the vehicle is estimated as follows. That is, the vehicle direction that has been determined so far is reset and replaced with the average value of the magnetic sensor data.

Then, in step (2), -0 and C-0 are set, and the process returns to step (2) to detect the position of the vehicle in the current cycle.

Although the vehicle position detection device of the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. For example, in steps [Yes] to ■ in Figure 1, the vehicle is driven in a straight line, and a sufficient number of geomagnetic sensor data are collected and averaged. It is also possible to reset the orientation. In addition, instead of immediately resetting the vehicle's orientation based only on the geomagnetic sensor data, for example, the processing in step (■) is performed, and the weight of using the geomagnetic sensor data here is increased, resulting in a gradual adjustment to the geomagnetic sensor data. It is also possible to get closer.

Various design changes can be made without changing the gist of the invention.

<Effects of the Invention> As described above, according to the vehicle position detection device of the present invention, due to an abnormality in the absolute azimuth data or a mismatch between the absolute azimuth data and the relative azimuth data, the absolute azimuth data is not used and the relative azimuth data is used. When the vehicle's direction is determined using only the vehicle for a certain distance or continues for a certain distance, the reliability of the absolute direction data is determined, and if it is determined to be reliable, the absolute direction data is used. I made it. Therefore, it is possible to prevent the accumulation of errors caused by continuing to use only relative orientation data, improving orientation detection accuracy.
As a result, the accuracy of vehicle position detection can be improved.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a vehicle position detection procedure, and FIG. 2 is a block diagram showing an example of the hardware configuration of the vehicle position detection device. 1... Locator, 11... Wheel speed sensor, 12...
・Geomagnetic sensor

Claims (1)

[Claims] 1. Distance sensor, absolute direction sensor on the vehicle, and a relative direction sensor installed, so that the is the mileage data output from the distance sensor. When calculating the distance traveled by a vehicle using data, Absolute orientation data, relative orientation sensor The relative orientation data output from The vehicle position can be determined by finding both directions. Abnormality in absolute orientation data, or Discrepancies between absolute orientation data and relative orientation data If a match is found, the mileage data will be used to The distance traveled by the vehicle determined by Excluding the data and relying only on the relative orientation data. The position of the vehicle is determined from the direction of the vehicle determined by Vehicle position detection device that calculates by dead reckoning At the location, for a certain distance or for a certain period of time. Absolute orientation data continues to be excluded a first determination means for determining whether the The first step to determine the reliability of absolute orientation data. 2. Judgment means; Absolute orientation data by the first determination means Exclusion status is constant mileage or constant running Determine whether the line lasted for a period of time, and the absolute orientation data is determined by the second determining means. When it is determined that the data is reliable, Reset the vehicle's orientation at the time, Vehicle determined from the above absolute direction data control means for replacing the direction of A vehicle position detection device characterized by: