JP3304027B2 - GPS receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a GPS orbiting the earth.
GPS (Global Posi
tioning System) Receiver.

[0002]

2. Description of the Related Art A GPS receiver receives radio waves from a plurality of satellites and obtains a navigation message (orbit information and time information) from an artificial satellite to determine an absolute position on the earth and a Doppler shift frequency. Is a system that can calculate the speed by measuring the speed.

Hereinafter, a conventional GPS receiver will be described with reference to the drawings. In FIG. 2 , reference numeral 1 denotes an antenna for receiving a radio wave from a satellite;
It is a detection unit that outputs to The positioning unit 3 determines the position of the receiver by setting simultaneous equations from the position of the satellite and the propagation time of the radio wave from the satellite to the receiver. GPS satellites are launched in six orbits at an altitude of about 20,000 km on Earth,
Currently, a total of 25 satellites are operating. The receiver can perform positioning calculation by simultaneously receiving at least three or more of these satellites. Then, the positioning calculation result and the navigation message are stored in the storage unit 4, and the tracking satellite selection unit 6 uses the current time of the RTC (Real Time Clock) 5 and the data of the storage unit 4 to determine the visible satellite at the current time. By making the determination and determining the satellite number to be set in the detection unit 2, it is possible to quickly receive the satellite and speed up the start of the positioning calculation without performing unnecessary scanning of the satellite.

[0004]

The object of the invention is to be Solved However, in the structure as described above, by any chance, if the stored information was wrong with the serial憶部, actually will select the satellite can not be received by the tracking satellite selecting unit, forever It is conceivable that the state in which satellites cannot be received continues for a long time.

[0005] The present invention is intended to solve the above problems, aims to save data of the receiver to provide a GPS receiver that can launch even if, immediately positioning calculation incorrect And

[0006]

In order to achieve the above object, a GPS receiver according to the present invention has a plurality of channels.
Detector, and the position of the satellite obtained by the detector and the satellite
A positioning unit that performs positioning calculation from the radio wave propagation time of the star;
Save the positioning results obtained at the positioning unit and the orbit information of the satellite.
A storage unit, an RTC indicating the current time, and a
Select the satellite to be tracked from the orbit information and the RTC
A tracking satellite selection unit, wherein the detection unit includes the plurality of channels.
Randomly scan at least one of the channels
One of the satellites other than the satellite selected by the tracking satellite selection unit.
When receiving any of the above satellites and receiving any satellite
The satellite's elevation angle is calculated and the satellite is out of the visible range.
If the initial position of the receiver saved in the storage unit is
Judging that it is positive, random scanning of all channels
Equipped with an initial position error detection unit
And features .

[0007]

[0008]

According to the above configuration, it is possible to always receive any satellite, it is possible to find the correct time from the time information in received satellite.

Further, when the initial position abnormality detecting section detects an abnormality in the initial position data, the satellite can be received without being dragged by the abnormal data in the initial position by performing random scanning on all the channels. It is possible to shorten the rise time of the positioning calculation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below in detail with reference to the drawings. Figure 1 is a diagram showing the configuration of a GPS receiver in real施例of the present invention. In FIG. 1, reference numeral 1 denotes an antenna for receiving a radio wave from a GPS satellite, and reference numeral 2 denotes a detection unit having a plurality of channels, which demodulates a radio wave of a spread spectrum satellite and collects navigation messages and satellite time information. 3 is to solve the simultaneous equations from the satellite position calculated from the navigation message (orbit information) collected by the detector 2 and the propagation time of the radio wave from the satellite to the receiver (Equation 1). Is a positioning unit that obtains the position of the receiver. Further, the positioning unit 3 can also calculate the velocity from the Doppler shift frequency obtained by the detection unit 2.

[0011]

(Equation 1)

The storage unit 4 stores positioning results, satellite orbit information, and the like. RTC5 is a counter indicating the current time of the receiver. The tracking satellite selection unit 6 obtains the position of the satellite from the orbit information of the satellite stored in the storage unit and the current time of the RTC 5, further determines the visible satellite from the position of the receiver stored in the storage unit 4, and determines the visible satellite. Determine the satellite to track. At this time, at least one channel of the detection unit 2
A satellite not selected by the tracking satellite selection unit 6 is scanned. Thus, even if the RTC time is wrong, one or more satellites can always be received. Since accurate time information is transmitted from the satellite, the tracking satellite selection unit 6 performs the calculation again using the time obtained from the satellite, so that the satellite in the visible range can be surely set to the detection unit 2 and the positioning calculation is performed. Rise time can be shortened.

[0013] Next, initial position abnormality detecting unit 7, the exact time of the satellite received, seeking the position of the satellite from the orbit information and recalculates the elevation angle of the satellite from the initial position of the receiver. If the initial position is correct, it should be within the visible range because it is a received satellite. If it is out of the visible range, the initial position is determined to be incorrect, and an instruction is issued to switch all the channels of the detector 2 to random scanning.
This ensures that you are not dragged to the wrong initial position,
A new satellite can be received.

[0014]

As described above, according to the present invention,
Among the detectors having a plurality of channels, at least one channel is randomly scanned and a tracking satellite selector is selected.
Receive one or more arbitrary satellites other than the satellite selected in
Calculate the elevation angle of the satellite, and determine that the satellite is out of the visible range
The initial position data saved by the initial position
Data abnormality is quickly detected and all channels are randomized.
Switch to scanning, reduce satellite scanning time and start positioning.
The effect of shortening the rising time is obtained.

[0015]

[Brief description of the drawings]

1 is a configuration diagram of a GPS receiver in real施例of the present invention.

FIG. 2 is a configuration diagram of a conventional GPS receiver.

[Explanation of symbols]

1 ... antenna, 2 ... detector, 3 ... positioning,
4 ... storage unit, 5 ... RTC, 6 ... tracking satellite selection unit, 7 ... initial position abnormality detection unit.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01S 5/00-5/14 G01C 1/00-1/14 G01C 21/00-21/24 G01C 23/00-25 / 00

Claims (1)

(57) [Claims] A detection unit having a plurality of channels; a positioning unit for performing positioning calculation based on a satellite position obtained by the detection unit and a radio wave propagation time of the satellite; A storage unit for storing the obtained positioning result and the orbit information of the satellite, an RTC representing the current time, and a tracking satellite selection unit for selecting a satellite to be tracked from the orbit information and the RTC of the storage unit; The detection unit randomly scans at least one of the plurality of channels, receives one or more arbitrary satellites other than the satellite selected by the tracking satellite selection unit, and receives an arbitrary satellite. When the satellite is received,
Calculation, and if the satellite is outside the visible range,
The initial position of the receiver saved in the storage unit is determined to be incorrect.
To switch all channels to random scanning
G provided with an initial position abnormality detection unit for performing
PS receiver.