JP2981025B2 - GPS data filtering processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS data filtering apparatus.

[0002]

2. Description of the Related Art Conventionally, there is a so-called self-contained navigation device as a navigation device for various moving objects such as automobiles, aircraft, ships and the like. This self-contained navigation device obtains a two-dimensional displacement (vector amount) of a moving object from direction data from a direction sensor and speed data from a speed sensor, and integrates the two-dimensional displacement with a reference point to obtain a current position. Is what you want. However, in the self-contained navigation device, since the detection errors of the respective sensors are accumulated as they are, some error removing means is required.

Therefore, a GPS (Global) using artificial hygiene as a positioning device in which accumulation of errors does not matter.
Positioning System) positioning devices have been developed. This GPS positioning device usually has three or more GPs.
It is configured to receive a radio wave from the S satellite and measure the position of the receiving point from pseudorange data including the time offset of the receiver between each GPS satellite and the receiving point, and the position data of each GPS satellite. .

[0004]

SUMMARY OF THE INVENTION However, GPS
Since the positioning device obtains the azimuth by measuring the change rate (velocity) of the pseudorange data due to the Doppler effect of the radio wave from the GPS satellite, if the moving speed of the receiving point is low, the accuracy of the azimuth data is reduced. There was a problem. Furthermore, when the receiving point is stopped, there is a problem that the speed data becomes larger than the actual speed due to the multipath of the radio wave, indicating incorrect azimuth data.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a GPS data filtering processing device that enables highly accurate current position estimation even when a reception point is in a low speed or stopped state. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a GPS positioning means for receiving a radio wave from a GPS satellite to measure a current position of the self, and an azimuth data from an azimuth sensor. Self-contained positioning means for measuring the current position of the vehicle from speed data from a speed sensor;
Data processing means for selectively outputting data from the positioning means or data from the self-contained positioning means, wherein the data processing means has a PDOP value equal to or less than a predetermined value, and outputs speed data from the GPS positioning means. Is greater than or equal to a predetermined value, and when the difference between the speed data and the speed data from the self-contained positioning means is within a predetermined value, the data from the GPS positioning means is output.

Further, GPS positioning means for receiving a radio wave from a GPS satellite to measure the current position of the vehicle, and self-contained positioning for measuring the current position of the vehicle from direction data from a direction sensor and speed data from a speed sensor. Means and the GPS
Data processing means for selectively outputting data from the positioning means or data from the self-contained positioning means, wherein the data processing means has a PDOP value equal to or less than a predetermined value, and outputs speed data from the GPS positioning means. Is greater than or equal to a predetermined value,
The difference between the speed data and the speed data from the self-contained positioning means is within a predetermined value, and the data from the GPS positioning means is continuously obtained three times within a predetermined time, and three times. When the azimuth data from the continuous GPS positioning means is within a predetermined value, the data from the GPS positioning means is output.

[0008]

The present position measurement by the GPS positioning means and the measurement of the current position by the self-contained positioning means are performed, and the PDOP value is equal to or less than a predetermined value, and the speed data from the GPS positioning means is equal to or more than the predetermined value. When the difference between the speed data from the GPS positioning means and the speed data from the self-contained positioning means is within a predetermined value, the data processing means
Data from the PS positioning means is selectively output. Alternatively, in addition to the above three conditions, the data processing means may obtain data from the GPS positioning means three times consecutively at an interval within a predetermined time, and receive data from the three consecutive GPS positioning means. GPS when azimuth data is within specified value
Data from the positioning means is selectively output. As a result, the data from the GPS positioning means is filtered, and the data from the GPS positioning means is adopted only when the measurement of the current position by the GPS positioning means has high accuracy, and the accuracy of the data from the GPS positioning means decreases. When there is, data from the self-contained positioning means is adopted.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a GPS data filtering apparatus according to the present invention. In FIG. 1, a filtering processing device includes a GPS antenna 3 for receiving a radio wave from a GPS satellite, and the GPS antenna 3
GPS receiver 4 connected to the output side of the receiver, a receiving point (a mobile body such as an automobile) based on a signal from the GPS receiver 4
GPS position measuring means 1 constituted by GPS type position calculating means 5 for recognizing the current position of the vehicle, traveling history based on signals from a direction sensor 6 for detecting a direction and a speed sensor 7 for detecting the speed of a receiving point A self-contained positioning means 2 constituted by a self-contained position calculating means 8 for recognizing the current position of the receiving point from the GPS, a GPS-type position calculating means 5, a speed sensor 7 and a self-contained position calculating means 8 And a data processing means 9 for performing data processing. Further, the data processing means 9 includes a storage device 10 such as a compact disk or a ROM storing map information and the like.
Are connected via the decoder 11 and CR
A display device 12 such as T is connected.

The GPS type position calculation means 5, the self-contained position calculation means 8 and the data processing means 9 are provided with a calculation circuit, a RAM connected thereto, and an R for holding a program of each means.
It consists of a microcomputer with OM. The GPS-type position calculating means 5 calculates the current position of the receiving point based on a signal from the GPS receiver 4 and outputs data to the data processing means 9.
Based on the signal from the speed sensor 7 and the current position of the receiving point, the data is output to the data processing means 9. The data processing means 9 selects data from the GPS positioning means 1 and data from the self-contained positioning means 2, and based on the selected data and map information around the current position drawn from the storage device 10. And the current position of the receiving point is displayed on the display device 12. Note that the GPS-type position calculation means 5, the self-contained position calculation means 8, and the data processing means 9 may be configured using dedicated calculators.

Here, selection of data from the GPS positioning means 1 and data from the self-contained positioning means 2 by the data processing means 9 will be described. The present invention is characterized in that the data processing means 9 selects data from the GPS positioning means 1 when the following three conditions are satisfied.

The PDOP value is equal to or less than a predetermined value.
Speed data from the GPS positioning means 1 is equal to or greater than a predetermined value. The difference between the speed data from the GPS positioning means 1 and the speed data from the speed sensor 7 is within a predetermined value.

The above PDOP (Position Di)
The “lution Precision” value is an index of how the error of the GPS satellite position is reflected on the position of the reception point in the GPS positioning. The larger the value, the larger the error of the positioning. Therefore, in the present invention, PDOP
The condition that the value is equal to or less than a predetermined value is one condition for selecting data from the GPS positioning means 1.
DOP = 4 is preferred. That is, under the arrangement situation of the GPS satellites whose PDOP value is 4, if the average error of the distance measurement to the GPS satellites is 10 m, the standard of the positioning error is 40 m as shown below. , Highly accurate positioning is possible.

Estimated positioning error = PDOP value × average error in distance measurement = 4 × 10 m = 40 m The speed data from the GPS positioning means 1 is determined to be equal to or more than a predetermined value because the GPS positioning is based on the GPS satellites. The azimuth is obtained by measuring the rate of change (speed) of the pseudorange data due to the Doppler effect of the radio wave. If the moving speed of the receiving point is low, the accuracy of the azimuth data will be reduced. To do that. And
It has been found that the minimum speed at which the accuracy of the azimuth data can be maintained high is preferably about 30 km / h.

Further, by assuming that the difference between the speed data from the GPS positioning means 1 and the speed data from the speed sensor 7 is within a predetermined value, it is possible to eliminate an azimuth data error due to multipath of radio waves. The predetermined value is 3
It is preferably about km / h.

In the present invention, when five conditions, which are obtained by adding the following three conditions to the above three conditions, are satisfied, the data processing means 9 sets the GPS positioning means 1
May be selected.

The data from the GPS positioning means 1 is obtained three times consecutively at an interval within a predetermined time. 3
The azimuth data from the GPS positioning means 1 which has been repeated consecutively is within a predetermined value.

The above-mentioned predetermined time is preferably about 2 seconds, and three times consecutively within two seconds.
As a requirement that data from GPS is obtained, a state in which data from GPS is received stably for the past several seconds from the present is maintained.

The predetermined value is preferably about ± 10 °, and when the azimuth data is within ± 10 ° three times in a row, the receiving point is in a straight-ahead state. GPS azimuth can be obtained.

Here, the GPS positioning means 1 will be described. FIG. 2 is a block diagram showing the GPS positioning means 1,
GPS antenna 3 has preamplifier 31 and bandpass filter 3
2, a crystal oscillator 35 for outputting a reference frequency signal, which is an overall timing control signal, and a clock signal for controlling the operation timing of the signal processing means 37 based on the reference frequency signal Is provided with a clock oscillation circuit 36 that forms
The mold position calculating means 5 is connected to the signal processing means 37.

The GPS receiver 4 receives a signal carrier of a GPS satellite based on a reference frequency signal oscillated by a crystal oscillator 35,
A frequency synthesizing circuit 41 for generating a signal having the same pattern as data relating to the position of the GPS satellite and the state of the clock in the GPS satellite, and a clock signal output from the clock oscillation circuit 36 and having a code signal having the same pattern as the ranging signal , And the output signals of the frequency synthesis circuit 41 and the code generation circuit 42
A data and carrier detector 43 for correlation detection of data and a carrier wave of orbits of a clock and a GPS satellite in a PS satellite, and a code signal output from the code generation circuit 42 for correlation detection of the distance measurement signal. And a code lock detector 44.

The azimuth sensor 6 constituting the self-contained positioning means 2 is a known geomagnetic sensor or a gyro compass, and detects the moving direction of the receiving point. A known rotation speed sensor or the like is used as the speed sensor 7 for detecting the speed of the receiving point, and the moving distance of the receiving point is calculated by integrating the speed of the receiving point by the speed sensor 7. Then, by accumulating the moving distance in accordance with the change in the moving direction of the receiving point detected by the direction sensor 6, the moving history of the receiving point can be obtained. As a result, the movement path from the reference point is calculated, and the current position is measured.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to FIG. First, the filtering processing device is activated, and radio waves from GPS satellites
When it is confirmed that the signal is received by the antenna 3 (S
1) The data processing means 9 determines whether or not the PDOP value is equal to or less than a predetermined value (in this case, 4 or less) (S).
2). When the determination is Yes (PDOP value is 4 or less), the data processing means 9 determines whether or not the speed data from the GPS positioning means 1 is a predetermined value or more (in this case, 30 km / h or more). This is performed (S3). When this determination is Yes, the data processing means 9
The difference between the speed data from the positioning means 1 and the speed data from the speed sensor 7 is within a predetermined value (in this case, 3 km / h or less)
Is determined (S4). If the determination is Yes, the data processing means 9 determines whether or not this reception is the first time (S5), and if the determination is No, the data from the GPS positioning means 1 The data processing means 9 determines whether or not it is obtained within the time (in this case, within 2 seconds) (S6). When this determination is Yes, the data processing unit 9 determines whether or not the continuous azimuth data from the GPS positioning unit 1 is within a predetermined value (in this case, within 10 °) ( S7) If the determination is Yes, the reception counter is incremented by one (S8) and GP
It is determined whether or not the data from the S positioning means 1 has been obtained three times in a row (S9). The direction data from 1 is selected by the data processing means 9 (S11).

On the other hand, if the data is not received by the GPS antenna 3 (S1), the data processing means 9 does not select the data from the GPS positioning means 1 and the above-mentioned (S2)
No determination is made in either (S3) or (S4)
In this case, the data processing means 9 does not select the data from the GPS positioning means 1 also. Further, when the reception is the first time (S5), the azimuth data from the GPS positioning means 1 is recorded (S12), the reception number counter is incremented by one (S13), and the data processing means 9 is used by the GPS positioning means 1. The filtering of the data from the GPS positioning means 1 is performed again without selecting the data from. In addition, the above (S
If the determination is No in any of 6) and (S7), the number of receptions is set to N = 2 (S14), the azimuth data from the GPS positioning means 1 is recorded (S15), and the data processing means 9 again executes the GPS positioning means. Filter the data from # 1. Further, when the data from the GPS positioning means 1 is not continuous three times (S9), the data processing means 9 does not select the data from the GPS positioning means 1.

One filtering process is performed as described above, and data from the GPS positioning means 1 is selected only when the filtering conditions (the above five conditions) are satisfied. By repeating this filtering process, GPS data having a large error when the moving speed of the receiving point is low or when there is a multipath of radio waves is eliminated, and a highly accurate current position estimation can be performed.

Also, as described above, the GPS positioning means 1
Is selected by the data processing means 9 (S1).
Each time 1) is performed, the azimuth sensor 6 constituting the self-contained positioning means 2 can be corrected based on the azimuth data. As a result, the frequency of correction of the direction sensor increases, and the positioning accuracy of the self-contained positioning means 2 improves.

In the flow chart shown in FIG. 3, the above-mentioned conditions are adopted as the filtering conditions, but in the present invention, the above conditions are adopted as the filtering conditions.
May be adopted.

[0028]

As described in detail above, according to the present invention, P
The DOP value is equal to or less than a predetermined value, the speed data from the GPS positioning means is equal to or more than the predetermined value, and the difference between the speed data from the GPS positioning means and the speed data from the self-contained positioning means is within the predetermined value. Only when the data from the GPS positioning means is selected, and in other cases, the data from the self-contained positioning means is selected, so that the current position can be estimated with high accuracy even when the receiving point is at a low speed or in a stopped state. Becomes Further, as a condition for selecting data from the GPS positioning means, data from the GPS positioning means is obtained three times consecutively at intervals within a predetermined time, and three consecutive GPS data are obtained.
By adding the condition that the azimuth data from the positioning means is within a predetermined value to the above three conditions, it is possible to estimate the current position even higher. In addition, by performing the filtering process of the data from the GPS positioning means,
The frequency of correction of the azimuth sensor increases, and the positioning accuracy by the self-contained positioning means improves.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a GPS data filtering processing device according to the present invention.

FIG. 2 is a block diagram showing GPS positioning means in the present invention.

FIG. 3 is a flowchart for one embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 GPS positioning means 2 Self-contained positioning means 3 GPS antenna 4 GPS receiver 5 GPS position calculating means 6 Direction sensor 7 Speed sensor 8 Self-supporting position calculating means 9 Data processing means 10 Storage Device 11 ... Decoder 12 ... Display device

Claims (2)

(57) [Claims] 1. GPS positioning means for receiving a radio wave from a GPS satellite to measure its own current position, and self-contained positioning for measuring its own current position from azimuth data from an azimuth sensor and speed data from a speed sensor. And data processing means for selectively outputting data from the GPS positioning means or data from the self-contained positioning means, wherein the data processing means has a PDOP value equal to or less than a predetermined value,
When the speed data from the S positioning means is equal to or more than a predetermined value and the difference between the speed data and the speed data from the self-contained positioning means is within a predetermined value, the data from the GPS positioning means is output. GP characterized by having
S data filtering processor. 2. GPS positioning means for receiving a radio wave from a GPS satellite to measure its own current position, and self-contained positioning for measuring its own current position from azimuth data from an azimuth sensor and speed data from a speed sensor. And data processing means for selectively outputting data from the GPS positioning means or data from the self-contained positioning means, wherein the data processing means has a PDOP value equal to or less than a predetermined value,
The speed data from the S positioning means is equal to or more than a predetermined value, the difference between the speed data and the speed data from the self-contained positioning means is within a predetermined value, and the data from the GPS positioning means is an interval within a predetermined time. 3 times in a row and 3
An apparatus for filtering GPS data, wherein the data from the GPS positioning means is output when the direction data from the GPS positioning means consecutively is within a predetermined value.