JPH10246766A - Location system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effect location of high precision with simple constitution by providing a moving body management center at a fixed position, constructing a differential reference station, and performing location by a differential system. SOLUTION: A moving body management center 10 is provided at a fixed position to construct a differential reference station therein. Measurement is performed by means of a GPS satellite in the differential reference station. A measuring approximate distance is found from an obtained measured result and a satellite position. Furthermore, a theoretically approximate position is found even from an exact position found by a survey and the satellite position. The correction value of the measured approximate position is found from a difference between these approximate positions, and erroneous correction information is transmitted to moving bodies 7-9. The moving bodies 7-9 calculate the correction value to the erroneous correction information. The differential reference station finds the average of the correction value collected from a plurality of the moving bodies 7-9, data exceeding a threshold value is excluded, average processing is performed, the obtained correction value is utilized at the time of calculating the erroneous correction information, and precision is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a location system using GPS satellites.

[0002]

2. Description of the Related Art In a GPS-only location system using GPS satellites, the nominal position error accuracy is as large as 100 m, and accurate location is not possible.

Here, in order to improve GPS positioning accuracy, positioning by a differential system is known. Since this positioning requires measurement of an error included in positioning information transmitted from a GPS satellite, a differential reference station equipped with a high-accuracy GPS tracking device is indispensable.

Further, since the position of the reference station has been accurately confirmed by surveying, if positioning is performed, GP
The error included in the positioning information transmitted from S can be checked. Therefore, if the error information obtained by the differential reference station is transmitted to the mobile as error correction information, the positioning accuracy of the mobile can be improved.

[0005] The position accuracy of this method is about 10 m, and it can be said that the positioning system is sufficient for performing high-accuracy location.

[0006]

However, it is difficult to use the differential reference station because it has not been developed yet.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a location system capable of providing a highly accurate location by a differential system with a simple configuration.

[0008]

A location system according to the present invention includes a mobile unit and a mobile unit management center for the mobile unit. The mobile unit management center is provided at a fixed position.
A differential reference station is constructed in the mobile management center, and location is performed by the differential method.

[0009]

According to a first aspect of the present invention, there is provided a location system comprising a mobile unit, a mobile unit management center for the mobile unit, a mobile unit management center provided at a fixed position, and a differential reference station at the mobile unit management center. Build and perform differential location.

As a result, a highly accurate location can be achieved without using an existing differential reference station which is difficult to use due to lack of maintenance.

[0011] In the location system according to the second aspect, the differential reference station may have a high precision GPS.
A general-purpose GPS receiver was used instead of the tracking device, and a plurality of general-purpose GPS receivers were used in order to suppress errors caused by noise generated in the general-purpose GPS receiver.

As a result, accurate correction information can be obtained at low cost. In the location system according to the third aspect, the mobile performs positioning based on the error correction information sent from the differential reference station, and notifies the differential reference station of a correction value for the error correction information. The accuracy of the transmitted error correction information can be improved.

[0013] In the location system according to the fourth aspect, the destination can be displayed very accurately on the electronic map of the specified mobile by setting the address by the mobile manager.

In the location system according to the fifth aspect, the location system is provided with a function of registering a telephone number and an address, and the destination is displayed on the electronic map of the mobile specified by setting the telephone number by the mobile administrator. Can be displayed accurately.

In the location system according to the present invention, the messages of the mobile manager and the driver of the mobile can be displayed on both electronic maps.

Next, an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) In FIG. 1, 1 is an antenna, 2 is a general-purpose GPS receiver, 3 is a positioning operation unit, 4 is an error correction information calculation unit, 5 is an operation unit, and 6 is a differential reference station. As shown in FIG. 3, the differential reference station 6 is installed at a mobile management center 10 (fixed position) that manages the mobiles 7, 8, and 9.

The operation of the differential reference station 6 configured as described above will be described with reference to the flowchart of FIG. At the differential reference station 6,
Positioning is performed using GPS satellites (A01). Where GP
In the positioning performed using the S satellite, a position at which the approximate distance (the distance calculated from the position of the satellite and the position of the terminal) matches the pseudo distance (the distance calculated from the arrival time of radio waves from the satellite) is determined. ing.

The radio wave arrival time from the satellite is measured with a slight delay due to the influence of the atmosphere, and the positioning information sent from the satellite includes a position error and the like, so the positioning result includes an error. In the positioning calculation, the terminal position is determined such that the pseudo distance and the approximate distance are equal. Therefore, these error factors can reduce the error by correcting the observed pseudo distance.

Therefore, the differential reference station 6 measures the approximate distance (A) from the obtained positioning result and the satellite position.
02). Further, a theoretical approximate distance (A03) is obtained from the accurate position obtained by the survey and the satellite position.
A correction value of the measured approximate distance is determined from the difference between these approximate distances (A04). The error correction information obtained in this way is transmitted to the moving body 7.

(Embodiment 2) By using the error correction information, the positioning accuracy can be improved. However, since the differential reference station 6 uses the general-purpose GPS receiver 2, the accuracy of the error correction information is not as good as that of the high-accuracy GPS satellite tracking device.

On the other hand, in the differential system, an error factor occurring outside the general-purpose GPS receiver 2 can be removed, but an error occurring inside the general-purpose GPS receiver 2 cannot be eliminated.

Therefore, in order to improve the accuracy of the error correction information of the differential reference station 6 using the general-purpose GPS receiver 2, it is necessary to suppress the error occurring in the general-purpose GPS receiver 2.

The error generated in the general-purpose GPS receiver 2 is largely caused by random noise generated in the analog part. Random noise is a random error. Generally speaking, the random error can be reduced by averaging.

In view of the above, a plurality of general-purpose GPS receivers 2 used in the differential reference station 6 are used, and error correction information is averaged to suppress an error factor occurring in the general-purpose GPS receiver 2.

(Embodiment 3) If a plurality of general-purpose GPS receivers 2 are used to increase the accuracy of error correction information, the cost will increase. Therefore, as shown in FIG. 3, a method is used in which a plurality of mobile units 7, 8, and 9 calculate an error with respect to the error correction information sent from the differential reference station 6, and send the error correction information to the differential reference station 6.

By the way, the right and left turns of the moving bodies 7, 8, 9 are as follows.
The determination can be made by an in-vehicle sensor provided on the moving bodies 7, 8, and 9 such as a gyro sensor. And
As shown in FIG. 4, the moving body 7 calculates the difference between the position where the vehicle turns right and left and the positioning position when the correction information is used, and derives the error included in the error correction information from this information. . The mobile unit 7 sends the correction value for the error correction information thus obtained to the differential reference station 6.
Send to

As shown in FIG. 5, the differential reference station 6 collects correction values for the error correction information transmitted from the plurality of mobile units 7, 8, and 9 for a certain period of time (B0).
1). However, there are cases where the mobile units 7, 8, and 9 incorrectly determine the location where the vehicle has made a right or left turn, or a case where an incorrect correction value is sent. However, if the mobile units 7, 8, and 9 have correctly determined the place where the vehicle turns right and left, the correction values sent from the mobile units 7, 8, and 9 are almost the same.

Therefore, an average of the correction values collected from the plurality of moving bodies 7, 8, and 9 is obtained, and data in which the difference between each correction value and the average value exceeds a predetermined threshold value is removed (B
02). An averaging process is performed on the averaged correction information (B03). The correction value thus obtained is used when calculating the error correction information, and the accuracy is improved.

(Embodiment 4) A function of displaying a destination of a moving object is added to the constructed differential location system.

This operation will be described with reference to the flowchart of FIG. The mobile management center 10 checks whether a mobile identification number has been set (C01). With settings,
A request for setting an address is made (C02). If the address is set (C03), the mobile management center 10 investigates the address position (C04), and then generates a position information packet (C03).
05). The mobile unit management center 10 transmits this position information to the specific mobile unit (C06). The mobile units 7, 8, and 9 that have received the position information display the information on the electronic map.

(Embodiment 5) Mobile management center 10
Has a telephone number and address registration function. The mobile management center 10 checks whether or not a telephone number has been set (D
01). If there is a setting, the telephone number in which the address is registered is checked (D02), and if it is registered, the address is searched (C04). Thereafter, a packet is generated (C0
5) Transmit the packet (C06).

(Embodiment 6) Mobile management center 10
In addition, a function to display the messages of the manager of the mobile unit and the driver of the mobile unit on both electronic maps is provided. In the case of a message, a specific character string is placed at the beginning of the message.

The mobile management center 10 checks a specific character string to check whether the message is a message. If the specific character string is detected, it is determined that the message is a set message when the specific character string is detected (E01), and a packet is generated (C05). The generated packet is transmitted to the management center or the mobile (C06), and the message is displayed on the electronic map.

[0034]

According to the present invention, it is possible to construct a high-accuracy GPS location system by a differential system, and pinpoint location without returning work is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a differential reference station according to an embodiment of the present invention.

FIG. 2 is a flowchart of correction information calculation processing according to one embodiment of the present invention;

FIG. 3 is a configuration diagram of a location system according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a process of acquiring a correction value for correction information according to an embodiment of the present invention.

FIG. 5 is a flowchart of a correction value calculation process performed by a reference station according to an embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of the location system according to the embodiment of the present invention.

[Explanation of symbols]

 6 Differential reference station 7, 8, 9 Mobile 10 Mobile management center

Claims (6)

[Claims] 1. A mobile communication system comprising a mobile unit and a mobile unit management center for the mobile unit, wherein the mobile unit management center is provided at a fixed position, and a differential reference station is constructed at the mobile unit management center to provide a location based on a differential system. A location system. 2. In the differential reference station,
2. A general-purpose GPS receiver is used in place of the high-precision GPS tracking device, and a plurality of general-purpose GPS receivers are used to suppress an error caused by noise generated in the general-purpose GPS receiver. Location system. 3. The location system according to claim 1, wherein the mobile unit notifies the differential reference station of a correction value for the error correction information sent from the differential reference station. 4. The location system according to claim 1, wherein a destination can be displayed on an electronic map of the designated moving object among the moving objects. 5. The location system according to claim 4, further comprising a function of registering a telephone number and an address. 6. The location system according to claim 4, further comprising a function of displaying a message on both electronic maps.