JPH0443729A - position determination device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a position determination device, and more specifically, it is suitably used to identify the position of a mobile station in a vehicle dispatch system consisting of a mobile station radio and a base station radio. The present invention relates to a position determination device.

2. Description of the Related Art A conventional position determination device includes a temperature compensation circuit and a slope correction circuit for correcting the difference in slope of the electric field strength signal versus output voltage characteristic of an A/D converter between individual devices. The distance of the mobile station was determined based on the magnitude of the digital signal output from the device. A conventional position determination device using this type of temperature compensation circuit and tilt correction circuit will be described below.

FIG. 2 shows the configuration of a conventional position determination device. In FIG. 2, I is an antenna that receives radio waves transmitted from a mobile station (not shown). 2 is a BPF, 3 is an amplifier, and 4 is an IF block, which form a receiving circuit. 5 is an amplifier, 6 is a temperature compensation circuit, 7 is a slope correction circuit, 8 is an LPF, 9 is an A/D converter, and 10 is a central processing section.

Next, the operation of the above conventional example will be explained.

In FIG. 2, the field strength signal related to the position of the mobile station output from the IF block 4 is converted into a digital signal via an amplifier 5, a temperature compensation circuit 6, a slope correction circuit 7, an LPF 6, and an A/D converter 9. After being converted into , it is introduced into the central processing unit 10 .

The central processing unit IO divides the distance to the mobile station into several stages based on this digital signal and determines the distance to the mobile station.

In this way, the position of a mobile station can also be determined by the conventional position determination device described above.

Problems to be Solved by the Invention However, the conventional position determination apparatus described above has a problem in that the position determination error caused by fading is large when the mobile station is moving. Another problem is that the temperature compensation circuit and the tilt correction circuit occupy a large area on the printed wiring board.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent position determination device that can eliminate fading and has a simple circuit configuration.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a field strength signal extraction means for receiving a radio signal and extracting a field strength signal proportional to the input field strength from the received signal; fading removal means for removing a fading component; amplification means for amplifying a field strength signal from which a fading component has been removed; a high frequency component removal means for removing a high frequency component from the amplified field strength signal; The apparatus includes an A/D conversion means that converts an electric field strength signal into a digital signal, and a determination means that determines the electric field strength from the converted digital signal.

Effect Since the present invention is configured as described above, the determination means
It has the effect of being able to determine the distance to the mobile station based on the digital signal of the amplified field strength signal from which fading components have been removed from the A/D conversion means.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. 2 indicate the same components as in FIG.

In FIG. 1, an antenna 1 receives radio waves transmitted from a mobile station (not shown).

2 is a BPF, 3 is an amplifier, and 4 is an IF block, which form a receiving circuit (field strength signal extraction means). 11
is a fading removal circuit (fading removal means), 5
8 is an amplifier (amplification means), 8 is an LPF (high frequency component removal means), 9 is an A/D converter (A/D conversion means), and 1o is a central processing unit (determination means).

Next, the operation of the above embodiment will be explained.

In FIG. 1, a radio signal transmitted from a mobile station (not shown) is received by an antenna l. This received signal is BP
The signal is introduced into the fading removal circuit 11 as an electric field strength signal via F2, amplifier 3, and IF block 4. A fading removal circuit 1 removes fading components from the field strength signal and sends it to an amplifier 5. The field strength signal from which the fading component has been removed is amplified by the amplifier 5, and then the high frequency component is removed by the LPF 8 and is introduced into the A/D converter 9.

The A/D converter 9 converts the amplified field strength signal from which fading components have been removed into a binary digital signal and introduces it into the central processing unit 1o. The central processing unit 10 determines the distance to the mobile station based on this digital signal.

In this way, according to the above embodiment, the central processing unit 10
The distance to the mobile station can be determined based on the binary digital signal of the amplified field strength signal from which fading components have been removed.

Effects of the Invention As is clear from the above embodiments, the present invention determines the position based on the field strength signal after removing the fading component from the field strength signal. This has the advantage that position determination errors caused by fading can be reduced.

Furthermore, since the signal processing of the field strength signal after the fading component has been removed is simplified, there is an advantage that the temperature compensation circuit and slope correction circuit according to the prior art can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a position determining device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional position determining device. 1...Antenna, 2...BPF, 3...Amplifier,
4...IF block, 5...Amplifier, 8...LP
F, 9...A/D converter, 10...Central processing unit, 1
1... Fading removal circuit agent Patent attorney Shigetaka Awano is one person

Claims (1)

[Scope of claims] Field strength signal extraction means for receiving a radio signal and extracting a field strength signal proportional to the input field strength from the received signal; Fading removal means for removing a fading component from the field strength signal; Fading component Amplifying means for amplifying the field strength signal from which the field strength signal has been removed; High frequency component removing means for removing the high frequency component from the amplified field strength signal; and A/D converting the field strength signal from which the high frequency component has been removed into a digital signal. A position determination device comprising: a conversion means; and a determination means for determining electric field strength from a converted digital signal.