JPH05203716A - Electronic navigation system for positional detection of mobile station - Google Patents

Abstract

PURPOSE:To provide more precise positional detection of a mobile station by increasing the amount of information on transmission position contained in transmitted signal from one transmitter in a stationary station from which the mobile station receives information, relating to an electronic navigation system in which a mobile station receives and processes radio signal the transmitter on a reference stationary station transmits for detecting its own position, in mobile radio communication system such as Automatic Vehicle Monitoring system. CONSTITUTION:The output of one transmitter TX on a stationary station B at reference position is transmitted by antennas ANT1-ANTn at multiple positions n, and in the reception signal of a mobile station M within the same area constituted of the output signal from that transmitter, each antenna number (sub-area sign), multiple number n, of transmitter TX's output of the stationary station and transmitter number (area number) are contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called distributed transmission type AVM for monitoring the positions of mobile stations moving one after another in areas of a plurality of distributed transmitters in a mobile radio communication system.
Like the (Automatic Vehicle Monitoring) system,
In order for the mobile station to know its position, the mobile station receives and processes a radio signal transmitted by a transmitter of a fixed station that serves as a reference, and thus relates to a radio navigation system in which the mobile station detects its position. In particular, the present invention relates to an electronic navigation system that detects the position of a mobile station moving in the same area by radiating the output of one transmitter of a fixed station at a reference position with an antenna. As an electronic navigation system, it is desired that the position detection accuracy of mobile stations be improved as much as possible.

[0002]

2. Description of the Related Art In a distributed transmission type AVM system for mobile radio communication, which is an example of a conventional electronic navigation system, a radio signal transmitted by a transmitter TX of each fixed base station B is transmitted by the transmitter of the base station B. It is a radio signal in which a TX number is coded and a carrier of radio frequency is a kind of so-called FSK modulation of FM modulation, and the output of the transmitter TX of the base station B is as shown in FIG.
As shown in (b), one omnidirectional antenna ANT radiates it. Then, the mobile station M existing in the area formed by the radio signal receives the signal,
It demodulated, processed the signal, and detected the position of its own M.

[0003]

In the conventional electronic navigation system, the output of one transmitter TX of each fixed base station B is one as in the AVM system of the distributed transmission method of mobile radio communication described above. The omnidirectional antenna ANT allows the mobile station M whose position is unknown to be uniformly radiated to the surroundings in order to know its own position and form a monitoring area. Therefore, the mobile station M receives from the base station B. In the signal, the number of position information output from the transmitter TX of the base station B is only one transmitter number (area number). Therefore, the accuracy of the position detection of the mobile station M that has processed the position information is limited to that the number of the position information output from the transmitter TX of the fixed station B is one. An object of the present invention is to increase the number of pieces of position information included in the output signal of one transmitter TX of the fixed station B at the reference position received by the mobile station M to improve the accuracy of detecting the position of the mobile station M. It is in.

[0004]

As shown in the principle diagram of FIG. 1, the basic configuration of the present invention for achieving this object is to output a plurality of n outputs of one transmitter TX of a fixed station B at a reference position. Are radiated by the antennas ANT1 to ANTn whose positions are different from each other, and the area constituted by the transmission output thereof is divided into a plurality of n to form a sub-area, which is fixed in the reception signal of the mobile station M receiving this. The number of each antenna (subarea code) and the number of the transmitter (area number) at a plurality of n positions in the transmission output of station B
Configure to include and.

[0005]

In the present invention, the output of one transmitter TX of the fixed station B at the reference position is divided into a plurality of n directional antennas ANT1 to ANTn having different installation positions and radiated, and a plurality of directional antennas ANT1 to ANTn are radiated within one area. Since it is divided into n to form a sub-area, the accuracy with which the mobile station M receives this radiation signal and detects its own position is
This is an improvement over the conventional case where the output of the transmitter TX of the fixed station B comprises only one area.

[0006]

FIG. 2 shows a case where the number of divisions of one area constituted by an output signal of a transmitter TX of a base station B of a distributed transmission type AVM system for mobile radio communication according to an embodiment of the present invention is four. As shown in Fig. 3 (a), one directional antenna ANT1 to ANT4 with four different installation positions is used for one area of 360 ° circumference.
In the case of 90 ° division, the transmitter TX of the base station B is shown in (a) and the receiver RX configuration of the mobile station M is shown in (b). In the transmitter TX of the base station B in FIG. 2A, first, as in the conventional case, the "modulation signal generation unit (FSK)" is used to input a signal that codes the transmitter number, for example, number 1, and perform FSK coding. For example, a carrier wave having a radio frequency of 800 MHz is generated in the "carrier wave generation unit", and a kind of frequency shift (FSK) modulation of FM modulation is performed in the "modulation unit (FM)". And the output of the "modulator (FM)"
The “hybrid circuit” divides the signal into four, and the four divided outputs are input to the four “modulators (AM)”. And 4
In each of the "modulators (AM)", a signal that encodes the number indicating the position information of the four directional antennas ANT1 to ANT4 of the transmission output is input, and for example, four low frequency waves of several hundred Hz are input. Each output f1 of the "modulation signal generator (low frequency)" that is converted to the modulation signal of
AM modulation, for example, is performed by ~ f4. Then, the radio signal FM-modulated by the transmitter number is AM-modulated by the four directional antennas ANT1 to ANT4, which represent the positional information of the transmission output, and the four signals in the 800MHz band are double-modulated. Wireless signal is amplified by each power amplifier to a predetermined power value, and each amplified output is amplified by four directional antennas ANT1 to ANT4 at different positions.
And radiate radio signals respectively. The radio signals radiated from the four directional antennas ANT1 to ANT4 respectively form sub-areas. If the mobile station M exists in the area of the base station B, the mobile station receives the radio signal at the receiver of the receiver RX, and the FM component therein is the demodulator (F
The M component is demodulated, and the AM component is further demodulated by the demodulation unit (AM) to obtain the information of the transmitter TX number (area number) and antenna number (subarea) of the base station B. From this fact, it is known that the mobile station M exists in the area constituted by the radio signal of the base station B, and whether the mobile station M is in the sub-area constituted by the radio signal output from any antenna. I understand. In addition, directional antennas ANT 1 to ANT
The sub-areas of the radio signals radiated from 4 may partially overlap each other, but even if the mobile station M cannot demodulate the AM component due to the interference that occurs,
Since the FM component can be demodulated, the number (area number) of the transmitter TX of the base station B can be received even in the worst case. In the above embodiment, the output of the transmitter of the base station B is transmitted by arranging four directional antennas in a radial pattern.
May be transmitted in any direction, or at any position. Also,
In the embodiment, the carrier wave is FM-modulated by the transmitter number and AM-modulated by the antenna numbers ANT1 to ANT4. However, the modulation method is not restricted and it is easy to separate each other.
Any type of modulation method may be used.

[0007]

As described above, according to the present invention, the accuracy of detecting the position of the mobile station can be improved by increasing the number of antennas having different installation positions for radiating the output of one transmitter of the base station. When applied to the AVM of the mobile radio communication system, the effect of improving the accuracy of position detection of the mobile station can be obtained.

[Brief description of drawings]

FIG. 1 is a principle diagram showing a basic configuration of an electronic navigation system for detecting the position of a mobile station according to the present invention.

FIG. 2 is a circuit configuration diagram of a base station device and a mobile station device of an AVM system for mobile radio communication according to an embodiment of the present invention.

FIG. 3 is a diagram of antenna arrangements of transmitters of base stations according to an embodiment of the present invention and a conventional example.

[Explanation of symbols]

ANT1 to ANTn are a plurality of n antennas with different transmission positions that divide and radiate the output of the transmitter TX of the fixed station B.

Claims (2)

[Claims] 1. One transmitter of a fixed station (B) at a reference position
(TX) outputs multiple (n) antennas (AN) with different transmission positions.
T1 to ANTn), and a plurality of (n) outputs of the fixed station transmitter (TX) are included in the received signals of the mobile station (M) that moves in the same area formed by the output signal of this transmitter. An electronic navigation system for detecting the position of a mobile station, characterized in that the number of each antenna and the number of the transmitter (TX) are included. 2. The transmitter (TX) of the fixed station (B) at the reference position of the electronic navigation system for detecting the position of the mobile station.
However, the carrier of the radio frequency modulated by the transmitter number (FM) is further modulated by the number of each antenna at the multiple (n) positions.
The electronic navigation system for position detection of a mobile station according to claim 1, wherein the (AM) and double-modulated radio signal is transmitted by each antenna at a plurality of (n) positions.