JP3231125B2 - GPS receiver - 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 receiver and, more particularly, to a technique for improving the initial setting of a GPS receiver.

[0002]

2. Description of the Related Art In a positioning means using a GPS system, when determining a satellite to be received and when calculating a reception position from a radio signal received from a GPS satellite, information on a rough reception position is required. It is known that the approximate position is initialized at the time of positioning. The approximate position used for such initial setting is, for example, when determining a satellite to be received, an angle between a line segment connecting the satellite and the approximate position of the GPS receiver and an tangent plane of the earth at the approximate position is determined. Asked,
It is used to select a GPS satellite whose intersection angle is equal to or larger than a predetermined angle, or to correct the installation position of a GPS receiver.

However, such approximate position information is
In a configuration in which the GPS receiver is externally input, the setting becomes complicated. For example, Japanese Patent Laid-Open No. 4-25878 discloses a GPS receiver that has a function of calculating a rough position, so that initial setting can be easily performed. Possible receivers have been proposed.
The GPS receiver disclosed in this publication receives a signal from a GPS satellite and detects a position of the GPS satellite, a storage unit storing information on the shape of the earth, and a satellite position detector. From the position of the GPS satellite detected by the means and the shape information of the earth read from the storage means, the position of the intersection where the straight line connecting the position of the GPS satellite and the center of the earth intersects the earth surface is calculated. Computing means for initially setting the intersection position as the approximate receiving position.

However, in the GPS receiver disclosed in this publication, there is no problem when the approximate position is obtained from one satellite, but in particular, when the approximate position is obtained from a plurality of satellites, this will be described below. There were technical challenges.

[0005]

That is, in the GPS receiver disclosed in the above publication, when the approximate position is obtained from a plurality of GPS satellites, a straight line connecting the position of each GPS satellite and the center of the earth is obtained. The position of the intersection where this straight line intersects the earth's surface is calculated, and the average of the position of the intersection for each GPS satellite calculated in this way is determined as the approximate position. Is that the shape of the earth is an ellipsoid, and the equation for finding the intersection of the ellipse and the straight line must be solved by the number of satellites, which makes the calculation process very troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a GPS receiver capable of obtaining approximate positions from a plurality of satellites by relatively simple arithmetic processing. Is to do.

[0007]

In order to achieve the above object, the present invention receives a signal from a GPS satellite,
Satellite position detecting means for detecting the position of a PS satellite, storage means for storing the shape information of the earth, and a figure formed by these satellites based on the coordinate positions of a plurality of GPS satellites detected by the satellite position detecting means. A coordinate center position is calculated, and an intersection point where a straight line connecting the coordinate center position and the earth center intersects the earth surface is calculated from the coordinate center position and the shape information of the earth read from the storage means. Computing means for initially setting the intersection position as the approximate receiving position.

[0008]

According to the GPS receiver having the above structure, the arithmetic means calculates the center position (center of gravity) of coordinates formed by a plurality of satellites in advance, and calculates the position of the center of gravity and the shape information of the earth read from the storage means. Therefore, the approximate position is calculated by calculating the position of the intersection where the straight line connecting the position of the center of gravity and the center of the earth intersects the surface of the earth, so that the calculation of the position of the intersection can be obtained by one calculation.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows the G according to the present invention.
1 shows an embodiment of a PS receiver. GPS shown in the figure
The receiver is a GP that receives radio signals transmitted from satellites.
An S antenna 1, a satellite signal detector 2 for receiving a signal received by the antenna 1 and detecting a signal from a satellite, a satellite position calculator 3, a satellite orbit information storage unit 4, a satellite automatic selector 5, , An earth shape storage unit 6, an arithmetic unit 7, a rough position storage unit 8, a positioning arithmetic unit 9, and a display unit 10.

The satellite signal detector 2 receives radio signals of the GPS satellites SV _{1 to} SV ₃₂ received by the antenna 1 and decodes an encrypted satellite number, satellite orbit information, transmission time information, and the like. And stores the decoded satellite orbit information of the successfully decoded satellite in the satellite orbit information storage unit 4.
To the satellite position calculator 3
Output to In the satellite position calculator 3, the satellite position detector 2
, The positions of each of the satellites SV _{1 to} SV ₃₂ are obtained and output to the arithmetic unit 7.

[0011] satellite orbit information storage unit 4, in the first use state of the GPS receiver, nothing since not stored, the radio waves from GPS satellites (SV ₁ ~SV ₃₂₎ received successively by the antenna 1, The received satellite radio signal is decoded by the satellite signal detector 2 to extract the orbit information of each of the satellites SV _{1 to} SV ₃₂ , which are sequentially stored in the satellite orbit information storage unit 4. The automatic satellite selector 5 selects a satellite currently receivable by the GPS receiver based on the satellite orbit information stored in the satellite orbit information storage unit 4 and determines which satellite number and which channel are to be received by the satellite. The signal is output to the signal detector 2.

In this type of receiver, since the earth shape is approximated to an ellipsoid, the earth shape storage unit 6 stores in advance the earth shape information such as the major and minor radii of the earth and the oblateness. The arithmetic unit 7 obtains the approximate position P shown in FIG. 2 from the satellite position information output from the satellite position calculator 3 and the earth shape information output from the earth shape storage unit 6, Store that value.

The positioning calculator 9 uses the satellite position information output from the satellite position calculator 3 and uses each of the GPS satellites SV _{1 to} SV ₁ .
A pseudo-calculation distance between ₃ and the installation position of the GPS receiver is obtained, and the pseudo-calculation distance is corrected by the approximate position information stored in the approximate position storage unit 8, and the corrected GPS receiver installation position is displayed. Output to the unit 10. In the GPS receiver configured as described above, the GPS receiver is installed at the positioning location, and the orbit information stored in the satellite orbit information storage unit 4 is used, or when the orbit information is not stored. Selects sequentially the radio signals from all the GPS satellites Nos. 1 to 32, receives them with the antenna 1, and selects a plurality of satellites which can receive the signals with the automatic satellite selector 5.

The plurality of satellites selected by the selector 5 are assigned to the satellite signal detector 2, and the plurality of GPS satellites SV ₁
Receiving a signal from Sv ₃ by the antenna 1, the satellite signal assigned satellite signal detector 2, each GPS satellite S
Extraction and transmission time information and orbit information V ₁ ~SV _3,
The orbit information is stored in the satellite orbit information storage unit 4. FIG.
FIG. 6 is an explanatory diagram when the approximate position P is determined by the calculator 7 in the present embodiment, and the approximate position P is determined by the following calculation. The calculation of the approximate position P shown in the figure, three GPS satellites SV ₁
Sv ₃ exemplifies a is selected, the calculation of the approximate position P, firstly, three satellites SV ₁ Sv ₃ selected
Are determined, and then the position of the coordinate center δ of the triangle formed by these three satellites is determined.

The intersection of the straight line connecting the coordinate center δ and the center C ₀ of the earth and the equation of the shape of the ellipsoid of the earth are determined. Are stored in the approximate position storage unit 8. However, this way is selected by all of the satellite SV ₁ Sv ₃₂ satellite automatic selector 5 again can be seen from the approximate position P obtained, the satellite is selected in this way, the satellite signal detector 2 is compared with a satellite that has already been allocated, and if there is a satellite that has not been allocated, additional allocation is performed.

Next, G detected by the satellite signal detector 2
When the number of PS satellites becomes three or more, a pseudo calculation between each GPS satellite and the GPS receiver is performed by the positioning calculator 9 using the satellite position information obtained by the satellite position calculator 3 and the value of the approximate position P. The distance is obtained, an equation is set using the pseudo-calculated distances for all the satellites, and the correction amount (latitude, longitude, height) from the approximate position P is set as an unknown value. In this case, the height correction becomes 0), the correction amount is added to the approximate position P to obtain an appropriate receiver position, and the appropriate receiver position thus obtained is displayed on the display unit 10. To be displayed.

In the GPS receiver constructed as described above, the arithmetic unit 7 calculates the coordinate center δ of a triangle formed by a plurality of satellites in advance, and the coordinate center δ and the earth shape storage unit 6 are calculated.
From the shape information of the earth read out from, the intersection position at which the straight line connecting the coordinate center δ and the earth center C ₀ intersects the earth surface is calculated to obtain the approximate position P, so that the calculation of the intersection position is 1 The initial setting of the GPS receiver can be performed easily and quickly.

In the above embodiment, the case where three GPS satellites are selected and the coordinate center δ of a triangle formed by these three satellites is obtained is exemplified. However, the present invention is not limited to this. Instead, four or more satellites may be selected, the center position of the coordinates may be determined using the four or more satellites, and the approximate position may be determined based on the coordinate center position.

[0019]

As described above in detail in the embodiments,
According to the GPS receiver of the present invention, the approximate position is obtained from a plurality of satellites by relatively simple processing.
Initial setting of PS receiver can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an overall configuration of a GPS surveying receiver according to the present invention.

FIG. 2 is an explanatory diagram when an approximate position is obtained in the GPS receiver.

[Explanation of symbols]

 Reference Signs List 1 antenna 2 satellite signal detector 3 satellite position calculator 4 orbit information storage unit 5 satellite automatic selector 6 earth shape storage unit 7 calculator 8 approximate position storage unit 9 positioning calculation unit 10 display unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01S 5/00-5/14

Claims (1)

(57) [Claims] 1. Receiving a signal from a GPS satellite,
Satellite position detecting means for detecting the position of the PS satellite; storage means for storing the shape information of the earth; and, based on the coordinate positions of a plurality of GPS satellites detected by the satellite position detecting means, a figure formed by these satellites. A coordinate center position is calculated, and an intersection point where a straight line connecting the coordinate center position and the earth center intersects the earth surface is calculated from the coordinate center position and the shape information of the earth read from the storage means. And a calculating means for initially setting the intersection position as a rough reception position.