JP3097264B2 - 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 for measuring a current position by measuring radio waves from artificial satellites.

[0002]

2. Description of the Related Art In recent years, GPS, which is being developed by the U.S. Department of Defense, has been widely used as a radio positioning system. The positioning by GPS is a method of measuring a delay time of a radio wave from an artificial satellite and obtaining a current position from a distance from an orbit. The navigation message transmitted from the satellite includes the orbit information of the transmitted satellite itself, the correction value of the clock,
It contains general orbit information of all GPS satellites. The general orbit information of all GPS satellites is called almanac,
It contains information such as available satellite directions and elevation angles.
That is, if a signal from one satellite is received, the orbit of another satellite can be known from the almanac.

FIG. 2 shows a basic configuration of a conventional GPS receiver. In FIG. 2, 1 is an antenna for receiving a signal from a satellite, 2 is a frequency converter for converting a high-frequency signal received by the antenna 1 into a frequency that can be easily handled, and 3 is a pseudo-distance between a message sent from the satellite and a pseudo-range. A signal processing unit for obtaining a current position from the information obtained by the signal processing unit 3;
Is a control unit for performing various controls based on the information obtained by the arithmetic processing unit 4, 6 is an operation unit for giving an instruction of the control performed by the control unit 5, and 7 is an information unit for giving the information specified by the control unit 5. This is a display unit for displaying on a display device or the like.

[0004] In the GPS receiver, signals from three or more satellites are required for positioning. Therefore, as the antenna 1, a microstrip antenna having a low directivity and a flat plate type as shown in FIG. 3 is usually used. The microstrip antenna can receive the signal in the best condition when the antenna is oriented perpendicular to the satellite to be received although the directivity is weak.

[0005]

The positioning accuracy greatly depends on the state of the signal from the GPS satellite and the elevation angle of the satellite. However, it is difficult for the observer to know in which direction the optimal satellite is located. Also, even if all the positions of the satellites in the sky are known, the signals of which satellites are currently being received, and tilting the antenna in any direction does not affect the signals of the satellite being received. It is difficult to know if it is possible to receive the

The present invention solves these problems,
It is an object of the present invention to provide a GPS receiver that receives a signal from a satellite in an optimal state and improves measurement accuracy.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention uses an almanac obtained by receiving a signal from one satellite to determine the position of another satellite and to determine the current antenna. Is detected by the control unit, the position of the antenna is instructed by the control unit to be in an optimum receiving state, and displayed by the display unit.

[0008]

According to the present invention, when positioning is performed by a GPS receiving apparatus, the above-described configuration receives signals from satellites in an optimal state, thereby improving positioning accuracy.

[0009]

FIG. 1 shows an embodiment of a GPS receiver according to the present invention. 1 to 7 in the figure are the same as in the conventional example. Reference numeral 8 denotes a tilt angle detection unit for detecting the tilt of the antenna.
In order to detect the tilt angle, a tilt angle sensor using a magnetic fluid is used.

The operation of the embodiment of the present invention will be described with reference to FIG. Here, it is assumed that there are four satellites having satellite numbers 1 to 4 in an arrangement as shown in FIG. 4A above the point where the observer intends to perform positioning. It is assumed that the observer has started positioning with the antenna of the GPS receiving device facing the zenith. Assume that a signal from the second satellite having the highest elevation angle has been received. This signal is received by the antenna 1 in FIG. 1, and is given as various information to the control unit 5 via the frequency conversion unit 2, the signal processing unit 3, and the arithmetic processing unit 4. Here, the controller 5 can grasp the positions of other satellites (satellite numbers 1, 3, and 4) from the almanac among the obtained information. In order to receive the signals of these satellites, the elevation angles of all the satellites with respect to the antenna are higher when the antenna is directed to the zenith as shown in FIG.
Signals can be received in a better state. Therefore, the tilt angle detecting unit 8 in FIG. 1 detects the tilt of the antenna, and the control unit compares the information with the tilt angle of the antenna that is optimal for signal reception. . FIG. 5 shows an example of the display unit 7. Examples of the display device include an LED and an LCD. Here, it is assumed that the control unit 5 wants to instruct the inclination of the antenna to be raised upward in FIG. In this case, the display element 1 is turned on (a). The observer recognizes this and tilts the antenna so that 1 is upward. When the inclination angle is insufficient, the display element 1 is not turned off (b). If the inclination angle is too large, the display element 1 is turned off and the display element 2 on the opposite side of the display element 1 is turned on (c). Then, when the tilt angle reaches the optimum, the display element 2 is turned off and the central display element 3 is turned on (d).
In this way, the observer can change the tilt angle of the antenna to an optimum state.

As described above, according to the present embodiment, the inclination angle detecting section of the antenna is provided to detect the inclination of the antenna, and the information is compared with the optimum receiving antenna inclination angle by the control section. If it is set, it is displayed on the display unit, so that the observer can easily set the antenna setting to the optimum state.

[0012]

According to the present invention as in the above embodiments,
When positioning, receive signals from satellites in an optimal state,
It is possible to provide a GPS receiving device that improves the positioning accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a GPS receiver according to one embodiment of the present invention.

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

FIG. 3 is a perspective view of a microstrip antenna.

FIG. 4 is a schematic diagram showing positions of GPS satellites and observation points.

FIG. 5 is a schematic diagram of a display section for indicating an inclination of an antenna.

[Explanation of symbols]

 Reference Signs List 1 antenna 3 signal processing unit 5 control unit 7 display unit 8 tilt angle detection unit

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01C 15/00 G01S 5/00-5/14 H01Q 3/00-3/46

Claims (1)

(57) [Claims] An antenna for receiving a signal from a GPS satellite, a signal processing unit for analyzing a signal from the antenna, a tilt angle detecting unit for detecting a tilt of the antenna,
The position of an unreceived GPS satellite is grasped from the information obtained by the signal processing unit, the information on the inclination of the antenna obtained from the inclination angle detection unit is compared, and the inclination of the antenna is adjusted to an optimal state for reception. A GPS receiving device comprising: a control unit for instructing; and a display unit for displaying the inclination of the antenna in a state optimal for reception instructed by the control unit.