JP3099249B2 - GPS receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a GPS (Global Positi
oning System: a navigation system using a navigation satellite).

[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.

[0003] Positioning by GPS is a method of measuring the delay time of a radio wave from an artificial satellite and obtaining the current self-position from the distance from a very accurate satellite orbit. The navigation message transmitted from the satellite includes the orbit information of the transmitted satellite itself,
Clock correction values, general orbit information of all GPS satellites, and the like are included. The general orbit information of all the GPS satellites is called almanac and includes information such as directions and elevation angles of available satellites. That is, if a navigation message is received from one satellite, the orbit of another satellite can be known from the almanac.

[0004] Then, by using the almanac obtained by receiving the navigation message from one satellite, the position of the other satellite is grasped, and the inclination of the current own receiving antenna is detected.
A technique has been developed in which a control unit instructs a reception antenna to be tilted so as to be in an optimal reception state, and the display unit displays the instruction.

FIG. 3 is a block diagram showing a basic configuration of a conventional GPS receiver using the above-described almanac. Reference numeral 1 denotes a receiving antenna for receiving a signal from a satellite.
(Hereinafter simply referred to as an antenna), 2 is a frequency conversion unit for converting a high frequency signal received by the antenna 1 into a frequency that can be easily handled, 3 is a signal processing unit for obtaining a pseudo distance with a message sent from a satellite, and 4 is An arithmetic processing unit for performing an arithmetic operation for obtaining the current self-position from the information obtained by the signal processing unit 3; a control unit 5 for performing various controls based on the information obtained by the arithmetic processing unit 4; Is an operation unit for giving an instruction of control performed by the control unit 7, a display unit such as a display for displaying information specified by the control unit 5, and 8 is an inclination angle detection unit for detecting the inclination of the antenna 1.

[0006] The conventional GPS receiver configured as described above operates as follows.

First, there are four GPS satellites having satellite numbers S1 to S4 in an arrangement as shown in FIG. 4A, for example, above the point where the observer intends to perform positioning. It is assumed that the positioning is started with the antenna 1 facing the zenith. Then, it is assumed that a signal from the second satellite S2 having the highest elevation angle can be received. This signal is received by the antenna 1 in FIG. 3, passed through the frequency conversion unit 2, the signal processing unit 3, and the arithmetic processing unit 4 and given to the control unit 5 as various information.

Here, the control unit 5 can grasp the positions of the other satellites S1, S3, S4 from the almanac among the obtained information. In order to receive the signals of these satellites, the antenna 1 is not directed to the zenith as shown in FIG.
If the beam pattern of the antenna 1 is directed to all the GPS satellites by tilting as shown in (b), the elevation angles of all the GPS satellites become higher, and signals can be received in a better state.
Then, the inclination angle of the antenna 1 is detected by the inclination angle detection unit 8 in FIG. 3, and the information is compared with the inclination angle of the antenna 1 optimal for signal reception by the control unit 5. The observer instructs the observer to tilt the antenna 1 based on the information shown on the display unit 7 and performs positioning by using a signal received at an optimum antenna tilt angle.

[0009]

However, in the above-mentioned prior art, a portable receiver having an integrated antenna can easily change the inclination angle of the antenna. However, it is difficult to easily change the inclination angle of the antenna in a receiving device of an antenna separated type, particularly, a type in which the antenna is installed at a position away from the display unit.

[0010] In view of the above, it is an object of the present invention to provide a GPS receiver capable of easily changing the inclination angle of an antenna.

[0011]

According to the present invention, there is provided an antenna for receiving a navigation message, a signal processing unit for analyzing the received navigation message, a tilt angle detecting unit for detecting a tilt angle of the receiving antenna, A tilt angle changing unit that adjusts the tilt angle of the receiving antenna, and a control unit that controls input / output of each unit. The control unit determines the position of another GPS satellite different from the above from information obtained by the signal processing unit. Understand, determine the tilt angle of the receiving antenna so as to be in an optimal receiving state for positioning, and compare the determined tilt angle with the tilt angle of the receiving antenna detected by the tilt angle detecting unit. If they do not match, the control unit instructs the tilt angle changing unit to inform the tilt angle changing unit that the tilt angle of the receiving antenna is adjusted to the optimum tilt angle for reception.

[0012]

According to the present invention, when performing positioning, a signal from a satellite is received in an optimal state, and even if the position of the satellite moves during positioning, the tilt of the antenna is adjusted to an optimal state each time. Can be easily given, the positioning accuracy can be improved, and the positioning time can be shortened.

[0013]

FIG. 1 is a block diagram showing a configuration of an embodiment of a GPS receiving apparatus according to the present invention.
Is the same as that shown in FIG. 3 above, and the other reference numeral 9 denotes an inclination angle changing unit for changing the inclination of the antenna 1.

The operation of one embodiment of the present invention will be described with reference to FIG.

A signal transmitted from a GPS satellite is received by an antenna 1 in the same manner as in the prior art, and a control unit 5 receives information via a frequency conversion unit 2, a signal processing unit 3, and an arithmetic processing unit 4. The control unit 5 grasps the positions of other satellites based on the almanac in the information received from the satellite first received. And
The inclination angle of the anthena 1 is determined so as to obtain an optimal reception state for positioning. Further, the determined tilt angle is compared with the information on the tilt of the antenna obtained from the tilt angle detecting unit 8, and if they do not match, information is provided to the tilt angle changing unit 9 to optimize the tilt angle of the antenna 1. State.

Even when the position of the satellite changes during reception, the information of the almanac and the inclination angle detector 8 are always kept.
By comparing the information from the antennas 1, the tilt angle of the antenna 1 can be kept in the optimum state.

FIG. 2 is a schematic diagram showing an example of a GPS receiving antenna provided with an inclination angle detecting section 8 and an inclination angle changing section 9. In the figure, 10 is a flat plate type microstrip antenna (hereinafter, referred to as MS antenna), 11 and 12 are actuators for changing the inclination of the MS antenna 10,
Each of them rotates in the direction of the arrow in the figure, and the combination enables the MS antenna 10 to be directed in a required direction. Although not shown, by installing a potentiometer at the same position as the actuators 11 and 12, the rotation angle of the actuator can be detected, and the tilt angle of the MS antenna 10 can be known from the detection information.

[0018]

As described above, the GPS receiving apparatus of the present invention compares the almanac information included in the received GPS satellites with the information from the tilt angle detection unit when performing positioning to determine the optimal reception state. The inclination of the antenna is changed so that the positioning can always be performed with high accuracy and the antenna adjustment time can be shortened.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram illustrating an example of a GPS receiving antenna according to the present invention.

FIG. 3 is a block diagram showing a basic configuration of a conventional GPS receiver.

FIG. 4 is a diagram showing positions of a GPS satellite and an observer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Receiving antenna, 2 ... Frequency conversion part, 3 ... Signal processing part, 4 ... Operation processing part, 5 ... Control part, 6 ... Operation part, 7 ... Display part, 8 ... Inclination angle detection part, 9 ... Change in inclination angle Part, 10 ... Microstrip antenna (MS antenna), 11,12 ... Actuator.

──────────────────────────────────────────────────続 き Continued on 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 (2)

(57) [Claims] 1. An antenna for receiving a navigation message sent from a GPS satellite, a signal processing unit for analyzing the received navigation message, an inclination angle detection unit for detecting an inclination angle of the reception antenna, and the reception antenna A tilt angle changing unit that adjusts the tilt angle of the control unit and a control unit that controls input and output of each unit. The control unit grasps the position of another GPS satellite different from the above from information obtained by the signal processing unit. The tilt angle of the receiving antenna is determined so as to be in an optimal receiving state for positioning, and the determined tilt angle is compared with the tilt angle of the receiving antenna detected by the tilt angle detecting unit, and the tilt angle is determined. If not, the control unit instructs the tilt angle changing unit to indicate the mismatch, and adjusts the tilt angle of the receiving antenna to an optimum tilt angle for reception. 2. The GPS receiver according to claim 1, further comprising a display unit for displaying information specified by the control unit.