JP2007003461A - Apparatus for measuring angle of side slip of mobile station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring an angle of side slip of a mobile station, which improves the angle of side slip in precision. <P>SOLUTION: The apparatus for measuring the angle of side slip of the mobile station comprises: an angular velocity sensor 10 and a GPS arithmetic device 12 which are mounted on the mobile station; an acceleration sensor 14 which is mounted on the center of gravity of the mobile station; and a side slip angle calculating means 20 which determines an integrated value (I) by carrying out an integration calculation from a value determined by adding a side slip angular velocity (dβ/dt) to a yaw angular velocity (r) acquired in the angular velocity sensor 10, and from a value determined by dividing an orbital acceleration (d<SP>2</SP>y/dt<SP>2</SP>) acquired in the acceleration sensor 14 by a forward velocity (v) acquired in the GPS arithmetic device 12, and which calculates the integrated value (I) as the angle of side slip (β). Since the acceleration sensor 14 is mounted on the center of gravity, accelerations caused by the side slip angular velocity (dβ/dt) are prevented from mixing therein, and only the orbital acceleration (d<SP>2</SP>y/dt<SP>2</SP>) can be detected. Thus, the accelerations caused by the side slip angular velocity (dβ/dt) are prevented from mixing in the acceleration sensor 14, thereby improving the angle of side slip (β) in precision. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lateral angle measuring device for a mobile station, and aims to improve the accuracy of the lateral angle.

As a method for measuring the side slip angle of a mobile station, it is necessary to accurately obtain the side slip angle by integral calculation from the measured values of the vehicle speed sensor, the acceleration sensor, and the angular velocity sensor. However, when an acceleration sensor is used, an error occurs due to road disturbance, drift, and the like, and an integrated value that accumulates these values is a large error. Therefore, as a method of reducing such an error, the relative azimuth angle is obtained from the positioning value obtained by the GPS antenna, the above acceleration integral value is not used, the error is reduced by subtracting the relative azimuth angle from only the angular velocity integral value, The accuracy of the sliding angle was improved (for example, see Patent Document 1).
JP 2005-017191 A

However, if the acceleration sensor is mounted at a location other than the center of gravity of the mobile station, the first term shown in Equation 1 of Patent Document 1 is caused by the angular velocity (dβ / dt) in addition to the revolution acceleration (d ² y / dt ² ). Will be affected by the acceleration. In addition, the component of the lateral slip angular velocity (dβ / dt) to be calculated by the difference between the first term and the second term of Equation 1 described in Patent Document 1 is reduced and appears as an error.

  The present invention has been made in view of the above points, and an object of the present invention is to eliminate the influence of the lateral angular velocity on the acceleration sensor and to improve the accuracy of the lateral sliding angle as compared with the conventional art.

(1) A mobile station side slip angle measuring device according to claim 1 includes an angular velocity sensor 10 and a GPS arithmetic device 12 mounted on the mobile station and a center of gravity of the mobile station, as schematically shown in FIG. A value obtained by adding the mounted acceleration sensor 14, the yaw angular velocity (r) obtained from the angular velocity sensor 10 and the lateral slip angular velocity (dβ / dt), and the revolution acceleration (d ² y / dt) obtained from the acceleration sensor 14. ² ) is integrated on the basis of the value obtained by dividing the forward speed (v) obtained from the GPS arithmetic unit 12 to obtain an integral value (I), and the integral value (I) is obtained as a side slip angle (β). And a side slip angle calculating means 20 for calculating as follows.

According to the first aspect of the present invention, since the acceleration sensor 14 is mounted at the center of gravity, mixing of acceleration due to the lateral slip angular velocity (dβ / dt) is prevented, and only the revolution acceleration (d ² y / dt ² ) is detected. it can. Further, although the angular velocity sensor 10 can only obtain a value {r + (dβ / dt)} obtained by adding the lateral angular velocity (dβ / dt) and the yaw angular velocity (r), the yaw angular velocity (r) is the revolution acceleration (d ² It is equivalent to a value obtained by dividing y / dt ² ) by the forward speed (v). Therefore, in the whole formula, the lateral sliding velocity (dβ / dt) is integrated, and this integrated value can be set as the lateral sliding angle (β). Thus, the accuracy of the side slip angle (β) can be improved as compared with the prior art in that the side slip angle velocity (dβ / dt) is prevented from being mixed.

(2) The mobile station side slip angle measuring device according to claim 2 is the mobile station side slip angle measuring device according to claim 1, and is mounted on the center of gravity and the front or rear of the axle, respectively. The lateral angle calculation means 20 is mounted on the center of gravity and the azimuth vector (ψ) obtained from the GPS antennas 18 and 16 mounted in front of or behind the axle. A difference value (β _GPS = ψ−ψ _TRK ) with respect to the velocity vector (ψ _TRK ) obtained from the GPS antenna 18 is obtained, and the integral value (I) is corrected with the difference value (β _GPS ) to thereby determine the side smooth angle ( β) is calculated.

According to the invention of claim 2, since the integral value (I) is corrected by the difference value (β _GPS ), the integral error of the integral value (I) can be eliminated. Since the integration error is eliminated in this way, the accuracy of the side slip angle (β) can be improved as compared with the conventional case.

According to the present invention, the acceleration sensor is mounted on the center of gravity of the mobile station to eliminate the influence of the lateral slip angular velocity, and the lateral force to be calculated by the difference between the first term and the second term of Equation 1 described in Patent Document 1. The component of the sliding velocity (dβ / dt) can be prevented from decreasing.
Furthermore, since the integral value (I) of the lateral slip angular velocity is corrected by the difference value (β _GPS ), the integration error of the integral value (I) can be eliminated. Since there is no integration error in this way, the accuracy of the side slip angle can be improved as compared with the prior art.

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

  First, FIG. 2 shows a conceptual diagram of the GPS system. This GPS system includes a mobile station 26 and a base station 24, and receives and processes carrier code signals (for example, C / A, P code, etc.) transmitted from a plurality of artificial satellites (specifically, GPS satellites). The figure shows an example of receiving and processing carrier code signals respectively transmitted from four GPS satellites 22a, 22b, 22c, and 22d. It is desirable to employ a kinematic DGPS combined with the base station 24 in order to improve the accuracy of the position measurement at the mobile station 26 as compared with the single GPS. When the kinematic DGPS is adopted, the mobile station 26 and the base station 24 are configured so that data can be transmitted and received by a data link mechanism using wireless communication (or wired communication).

  The base station 24 has a position (Xk, Yk, Zk) in the earth coordinate system specified, and can receive a carrier code signal transmitted from the GPS satellites 22a, 22b, 22c, 22d, that is, a GPS antenna or an arithmetic unit. Etc. An arithmetic device (for example, a personal computer or the like) decodes the received signal by executing a predetermined processing program.

  The mobile station 26 includes the angular velocity sensor 10, the GPS arithmetic device (speed sensor) 12, the acceleration sensor 14, the GPS antennas 16 and 18, the arithmetic device (corresponding to the side slip angle calculating means 20) and the like shown in FIG. In particular, the acceleration sensor 14 and the GPS antenna 18 are mounted on the center of gravity G of the mobile station 26 (see FIG. 3), and the GPS antenna 16 is mounted in front of or behind the axle of the mobile station 26. The arithmetic unit includes a CPU, a ROM, a RAM, an input / output circuit, etc., receives and stores a carrier code signal transmitted from the GPS satellites 22a, 22b, 22c, and 22d, and communicates with the base station 24 through a data link mechanism. Transmission / reception is performed to correct the position data.

The kinematic DGPS is composed of GPS satellites 22a, 22b, and 22c by a GPS antenna provided in the base station 24 whose position (Xk, Yk, Zk) is accurately known and GPS antennas 16 and 18 provided in the mobile station 26. , 22d, the variables of the coordinates (x, y, z) of the positioning point and the error (Δt) of the timepiece are obtained.
Then, the measurement results of the base station 24 whose exact positions (Xk, Yk, Zk) are known are compared, and the difference is transmitted as correction data to the mobile station 26. The mobile station 26 transmits the correction data to the mobile station 26. The measured values obtained by the GPS antennas 16 and 18 are corrected.
According to the DGPS, the position of the mobile station 26, that is, the positions of the GPS antennas 16 and 18 can be accurately obtained at predetermined time intervals (for example, 0.2 seconds). An azimuth vector (ψ) representing 26 axle directions is obtained, and a velocity vector (ψ) is obtained from the base line length and relative angle of the GPS antennas 16 and 18.

The side slip angle β is a value (r + dβ / dt) obtained from the angular velocity sensor 10, a revolution acceleration (d ² y / dt ² ) obtained from the acceleration sensor 14, and a forward speed (v) obtained from the GPS arithmetic unit 12. Based on the above, the following equation 1 can be used. Note that the value obtained from the angular velocity sensor 10 is equal to a value obtained by adding the yaw angular velocity (r) and the lateral smoothing angular velocity (dβ / dt).

In the above formula 1, since the acceleration sensor 14 is mounted on the center of gravity G of the mobile station 26 (see FIG. 3), mixing of acceleration due to the lateral slip angular velocity (dβ / dt) is prevented, and the revolution acceleration (d Only ² y / dt ² ) can be detected. In addition, the first term of Equation 1 is a value obtained from the angular velocity sensor 10, and among these, the yaw angular velocity (r) is equivalent to the second term of Equation 1. Therefore, in the whole of the equation 1, only the lateral sliding velocity (dβ / dt) is integrated, and this integrated value becomes the lateral sliding angle (β). Thus, the accuracy of the side slip angle (β) can be improved as compared with the prior art in that the side slip angle velocity (dβ / dt) is prevented from being mixed.

Here, a case where the mobile station 26 moves in a curved manner, such as traveling on a curve, will be considered with reference to FIG. Consider a case in which the mobile station 26 moves in a curve along a locus 28 as shown in FIG. At the current position P where the vertical speed u and the horizontal speed v are generated by turning, an azimuth vector (ψ) indicating the axle direction of the mobile station 26 and a speed vector (ψ _TRK ) at which the mobile station 26 is moving Will occur. The former azimuth vector (ψ) is obtained by the GPS antennas 16 and 18, and the latter velocity vector (ψ _TRK ) is obtained by the GPS antenna 18.

Using the values (ψ, ψ _TRK ) obtained from the GPS antennas 16 and 18, a difference value (β _GPS = ψ−ψ _TRK ) is obtained. This difference value (β _GPS ) accurately represents the side slip angle, and the integral value (I) calculated by the above equation 1 includes an integral error. Therefore, if correction is performed by subtracting the difference value (β _GPS ) from the integral value (I) of Equation 1, errors due to skidding can be eliminated.

In the above formula 1, the integral value (I) accumulates with the passage of time, so correction by the difference value (β _GPS ) needs to be performed every required time interval t _d (for example, 0.2 seconds). As shown in FIG. 4, when the correction by the difference value (β _GPS ) is not performed, the value changes like an integral value (I) drawn by a two-dot chain line. By correcting the integral error (I-β _GPS ) with β _GPS at every time interval t _d , the accuracy of the side slip angle β can be increased. Thus, by increasing the accuracy of the side slip angle β, as a result, the accuracy of the current position P of the mobile station 26 can also be increased.
The invention of the present application can be applied to various measurement methods such as a single GPS in addition to the application example of the measurement method using DGPS.

It is a block diagram showing the example of composition of the present invention typically. It is a conceptual diagram of a GPS system. It is a figure explaining the method of correct | amending the noise by skidding. It is a figure explaining the relationship between an integral value, a difference value, and a side smooth angle.

Explanation of symbols

10 angular velocity sensor 12 GPS arithmetic unit (speed sensor)
14 Acceleration sensor 16, 18 GPS antenna 20 Side slip angle calculating means 22a, 22b, 22c, 22d GPS satellite (artificial satellite)
24 base station 26 mobile station

Claims (2)

An angular velocity sensor and a GPS arithmetic unit mounted on the mobile station;
An acceleration sensor mounted on the center of gravity of the mobile station;
A value obtained by adding the yaw angular velocity (r) obtained from the angular velocity sensor and the lateral angular velocity (dβ / dt) and the revolution acceleration (d ² y / dt ² ) obtained from the acceleration sensor are obtained from the GPS arithmetic unit. Side slip angle calculating means for obtaining an integral value (I) by performing integration based on the value divided by the forward speed (v) and calculating the integral value (I) as the side slip angle (β). A lateral slip angle measuring apparatus for a mobile station, comprising: The mobile station side slip angle measuring device according to claim 1,
It has a GPS antenna mounted on the center of gravity and on the front or rear of the axle,
The lateral slip angle calculating means calculates a difference between the azimuth vector (ψ) obtained from the GPS antenna mounted in front of or behind the center of gravity and the axle and the velocity vector (ψ _TRK ) obtained from the GPS antenna mounted on the center of gravity. value (beta _GPS) asking the integral value the difference value (I) (β _GPS) lateral slip angle by correcting by (beta) lateral slip angle measuring device of the mobile station and calculates a.

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