JPH08304092A - Method and system for detecting position of moving body - Google Patents

Abstract

PURPOSE: To detect the position of a moving body by obtaining the relative positional data obtained from positioning using the carrier phase by a GPS receiver and from positioning using an inertial navigation system in real time along with a GPS time data. CONSTITUTION: Blocks 11, 12 represent a GPS reference station antenna and a first receiver while blocks 13, 14 represent a transmitter for transmitting a data of reference GPS to a moving body and a data transmission antenna. GPS antennas 1, 2, a GPS receiver 3, a data antenna 4 and a data receiver 5 constitute a second receiver mounted on the moving body. A positional data affixed with a GPS time label at the time of measurement of relative position from a reference position is outputted at unit clock of 1sec. A positional data computer 10 fetches and stores an INS positional data affixed with time label and performs the positioning of the moving body in real time depending on the state of positional detector, i.e., whether the positional data of GPS has a measured time interval (normally, 1sec) or smaller time interval (e.g. 0.1sec).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a position of a moving body using kinematic (dynamic) positioning using a plurality of GPS receivers.

[0002]

2. Description of the Related Art In relative position detection (Differential GPS) in which radio waves from GPS satellites are simultaneously received at a plurality of receiving points and a relative positional relationship between the receiving points is obtained, it is known that interferometric positioning is highly accurate. There is. Then, in the interferometric positioning using the carrier phase, when two receivers are installed on the receiving point and the carrier positioning is observed and the relative position between the receivers is determined, the positions are already known accurately. Kinematic (dynamic) GPS positioning refers to a method in which one receiver is installed at a point and another receiver placed at the unknown point side is moved one after another to continue position detection.

[0003]

With this kinematic position detecting method, it is possible to detect the position with an accuracy within a few millimeters. However, during a series of observations, the position of the position is determined by intermittent GPS radio waves and calculation by the receiver. Since the detection data can be output only about every 1 second, it is difficult to detect the position at a shorter time interval.

On the other hand, in the position detection by the INS (Inertial Navigation System), it is possible to obtain position data at a necessary time interval, but the error becomes large with the passage of time, and it is not suitable for position detection for a long time. It was This is INS
Is because the acceleration and the angular velocity are detected and the moving position and the direction are obtained, so that the error due to the integration is accumulated when operating for a long time.

Therefore, an object of the present invention is to combine the advantages of the positioning using the carrier wave phase by the GPS receiver and the positioning by the inertial navigation system, and to obtain the position data within a time shorter than the position detection interval of the GPS receiver. Also aims to provide a method and apparatus for detecting the position of a moving body that can be obtained in real time.

[0006]

In order to achieve this object, the method for detecting the position of a moving body according to the present invention is to install a first GPS receiver at a fixed reference position in detecting the position of the moving body. The mobile unit is equipped with a second GPS receiver, and both G
According to the inertial navigation system, the relative position of the moving body with respect to the reference position is obtained from GPS interferometry using the carrier wave phase by the PS receiver, and the position data and GPS time data obtained from both GPS receivers are separately obtained. The relative position data of the moving body is calibrated, the calibrated position data is used as the relative position data of the moving body, and the position of the moving body is detected in real time.

The position detecting device for a moving body of the present invention is a position detecting device for detecting the position of a moving body, wherein the device is installed at a fixed reference position and is capable of GPS interferometry using carrier wave phase. A first GPS receiver, a second GPS receiver mounted on the mobile body and capable of GPS interferometric positioning using a carrier phase, and a relative position of the mobile body with respect to the reference position based on the interferometric positioning of both GPS receivers. And a second calculation means for calculating the relative position of the mobile body with respect to the reference position by the inertial navigation system, and relative position data of the mobile body obtained by the second calculation means. Is provided with a relative position data obtained from the first calculation means and a calibration means for calibrating the GPS time data, and the output of the calibration means is used as the position data of the moving body to move in real time. It is characterized in that to detect the position of the body.

[0008]

[Example] When it is attempted to accurately control the position of a moving body in a three-dimensional manner in a wide area, it is necessary to know the accurate position in real time. A local horizontal coordinate system for a certain reference position (horizontal east-west with respect to the gravity direction at that point,
The relative position of the moving body can be accurately measured by the GPS relative positioning method at the north-south and heights E, N, and H), but the position is determined by the data transmission time of the reference station from the reference station to the moving body and the calculation time of the position calculator. It is not possible to know in real time due to data delay and time interval. Meanwhile IN
In S (Inertial Navigation System), position data is output in real time, but since the acceleration of the moving body is double integrated to obtain the moving distance, it is proportional to the square of the elapsed time when there is a bias in the accelerometer and gyro. Then the error becomes large and it is not possible to know the position accurately. It is the method and apparatus of the present invention that ameliorates each of these drawbacks and combines the advantages of both.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a block diagram of the configuration of the first embodiment of the present invention. Blocks 11 and 12 are a GPS reference station receiving antenna and a GPS receiver, respectively, which constitute the first GPS receiver installed at a fixed reference position in the present invention, and blocks 13 and 14 respectively transmit data. And a data transmission antenna, which is a data transmitter for transmitting reference GPS data to a mobile body.

The GPS receiving antenna 1, the GPS receiving antenna 2, the GPS receiver 3, the data receiving antenna 4 and the data receiver 5 constitute a second receiver mounted on the mobile body according to the present invention. The relative position (including E, N, and H described above) from the reference position, the position data with the GPS time label at the time of measuring the relative position, and the clock in units of 1 second are output.

The GPS antennas 1 and 2 are installed on the moving body at intervals of several meters in the Y-axis direction of moving body coordinates X, Y, Z (Y: traveling direction, X: lateral direction, Z: height direction). And plays a role in determining the direction of the moving body when the moving body position detecting device is initialized. The direction of the moving body can also be determined by the geomagnetic azimuth meter 9.

The synchronizing signal generator 6 has the same interval as the output of the GPS position data synchronized with the received GPS clock (1 second interval), and a shorter time interval for position measurement to be obtained (for example, 0.1 seconds). Output the clock according to the interval.

Blocks 7, 8, 9 and 10 respectively constitute an inertial navigation system (INS) with a gyro, an accelerometer, a geomagnetic compass, and a position data calculator.
With a device that can measure the three dimensions of H, at a predetermined position measurement time interval (for example, 0.1 second intervals), the distance moved within that time interval is labeled with the measurement time and output. The position data calculator 10 captures and stores the INS position data with a time label, and stores the state of the position detection device, that is, the time when the GPS position data was measured (usually 1 second interval) or the time at a finer time interval ( Positioning of the moving body is performed in real time as described below, depending on whether (for example, every 0.1 second).

Reference will now be made to FIG. 2 of the accompanying drawings for a description of real-time positioning. The line described above the figure represents the time of the GPS clock, the interval is 1 second interval, t0 is the current time, t-4, t-3, t.
-2, t-1, t + 1 are 4 seconds before t0, 3 respectively
It is assumed that it is two seconds before, two seconds before, one second before, and one second after. The line described below represents the time of INS data acquisition, and the upper line is further divided into ten equal intervals to give 0.1 second intervals. What is important here is that it takes time for interferometric positioning and arithmetic processing after the signal from the satellite is captured by this position detection system until it is measured as GPS position data with a time label. There is a delay. In this explanation, the delay is 2 seconds.
Therefore, the position data at the current time t0 is the data based on the GPS signal received at the time t-2, and is referred to as, for example, (t-2) GPS position data.

Now, going back to the present article, the time when the GPS position data was first measured (t0, t + 1, t + 2, etc.)
A method of determining the current position in will be described. GPS
At time t0 when the position data is measured, the gyro angle data of the GPS position data of (t-3) and the GPS position data of (t-2) are taken in, and the difference is within the required measurement accuracy (almost linear movement). In this case, the sum of the INS position data from the time (t-3) to the time (t-2) is added to the GPS position data (t-3) to obtain (t
-2) Position data.

Next, the position data of the moving body obtained by adding the GPS position data of (t-3) and the integration of the INS position data from the time of (t-3) to the time of (t-2) and (t-
The bias of the INS acceleration is obtained from the difference between the position data of the mobile body and the position data of the mobile body obtained in 2), and the velocity error of the INS from the time (t-3) to the time (t-2) is obtained. The speed error of this INS is added to or subtracted from the speed at the time of (t-2) to correct the speed, and the moving distance by the INS from the time of (t-2) to the current time t0 is recalculated. The moving distance is integrated and added to the GPS position data of (t-2) to obtain the current position of t0. That is, the position of the moving body is detected in real time. On the other hand, when the difference in the rotation angle based on the gyro data is equal to or higher than the required measurement accuracy (when the moving body is rotating), the speed is not corrected and the movement distance by the INS from the time (t-2) to the current time t0. Is added up and added to the GPS position data of (t-2) to obtain the position of the moving body at the present time t0. That is, the position of the moving body is detected in real time. When the velocity correction is not performed for such a long time that the required measurement accuracy cannot be guaranteed by the INS independent measurement, the mobile body is temporarily stopped and the current position and the mobile body velocity are corrected from the GPS position data.

Next, when the current time is at a time of a finer time interval between GPS position data measurement times, the current position is the latest GPS position data from the time of the latest GPS position data to the current time. The integrated value of the moving distance by INS is added to obtain the current position, and the position of the moving body is detected in real time. Next, a second embodiment of the present invention will be described. In the second embodiment, the accelerometer of the block 8 shown in FIG. 1 is replaced with an axle tachometer of a moving body. Example 1
According to the time interval of position measurement required instead of INS,
The number of rotations of the axle of the moving body is measured, and the moving amount of the moving body in the moving body coordinate system is obtained. The moving body coordinate system is converted to the local horizontal coordinate system according to the rotation angle of the gyro of the movement amount, and the measurement time is labeled and stored in the position data calculator in the same manner as the INS movement amount data of the first embodiment to perform the position calculation. To do. Furthermore, by checking the detected position data with previously created map data and confirming the current position on the map data, it is possible to easily confirm the position in the field. Further, when detecting the orientation such as the direction and angle of the mobile body, the GPS receiving antennas 1 and 2 installed on the mobile body side are switched, and a plurality of position data and movement amount data corresponding to the respective GPS receiving antennas are obtained. Then, the posture data of the moving body is detected by the triangulation method based on the obtained values.

Although the present invention has been described in detail with reference to several embodiments, the present invention is not limited to these embodiments and various modifications and changes can be made within the scope of the invention by those skilled in the art. It will be obvious to me.

[0019]

According to the method and apparatus of the present invention, the GPS
Since the relative position of the moving body with respect to the reference position is detected by combining the advantages of the interferometric positioning using the carrier phase by the receiver and the positioning by the inertial navigation system, the moving position of the moving body can be accurately and almost continuously in real time. Can be detected.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing a time chart of a GPS clock signal and an INS acquisition clock signal.

[Explanation of symbols]

 1, 2 GPS receiving antenna 3, 12 GPS receiver 4 Data receiving antenna 5 Data receiver 6 Sync signal generator 7 Gyro 8 Accelerometer 9 Geomagnetic compass 10 Position data calculator 11 GPS reference station receiving antenna 13 Data transmitter 14 Data Transmitting antenna

Front Page Continuation (72) Inventor Hiroshi Saito 1230, Mukayama, Naka-machi, Naka-gun, Naka-gun, Ibaraki Prefecture Crop Growth Management System Research Institute, Mito Plant (72) Inventor Hideo Kawakami 5-6-16 Ikegami, Ota-ku, Tokyo No. Ikegami Tsushinki Co., Ltd.

Claims (6)

[Claims] 1. When detecting the position of a mobile unit, a first GPS receiver is installed at a fixed reference position, a second GPS receiver is mounted on the mobile unit, and the carrier wave phase by both GPS receivers is set. The relative position of the moving body by the inertial navigation system, which is obtained from the GPS interferometric positioning using the GPS interferometric positioning and is separately obtained from the position data obtained from the GPS receivers and the GPS time data. A method for detecting the position of a moving body, which comprises calibrating data, using the calibrated position data as relative position data of the moving body, and detecting the position of the moving body in real time. 2. The method for detecting the position of a moving body according to claim 1, wherein the calibration of the position data by the inertial navigation system is repeated at predetermined time intervals. 3. The position of a mobile body according to claim 2, wherein the position data detected in real time is collated with map data created in advance, and the current position is confirmed on the map data. Detection method. 4. The method according to claim 1, wherein the second GPS receiver is equipped with a plurality of receiving antennas, and triangulation is performed based on the obtained relative position data. A method for detecting the position of a moving body, comprising detecting the posture of the moving body in real time. 5. The position of a moving body according to claim 4, wherein at least one GPS receiver among the plurality of GPS receivers is also used for position detection on the map data. Detection method. 6. A position detecting device for detecting the position of a moving body, the device being a first GPS receiver installed at a fixed reference position and capable of GPS interferometric positioning using a carrier phase, and a moving body. A second GPS receiver which is mounted on the vehicle and is capable of GPS interferometric positioning using a carrier wave phase; and a first arithmetic means for calculating the relative position of the moving body with respect to the reference position from the interferometric positioning of both GPS receivers. Second calculating means for calculating a relative position of the moving body with respect to the reference position by the inertial navigation system, and relative position data of the moving body obtained by the second calculating means are obtained from the first calculating means. The relative position data and the calibration time for calibrating the GPS time data are provided, and the output of the calibration means is used as the position data of the moving body to detect the position of the moving body in real time. Position detection device for moving objects.