JPH02247590A - Position measurement system - Google Patents

Abstract

PURPOSE:To narrow the band of a signal and to take a measurement with high position accuracy by calculating the distances from a master station and slave stations to a mobile station from time differences which are obtained at the respective stations and then determining the position of the mobile station. CONSTITUTION:When a known time difference ts1 is generated because of the distance between the master station 1 and a 1st slave station 3 and a known time difference ts2 is generated because of the distance the master station 1 and a 2nd slave station 4, the distances l1, l2, and l3 from the master station 1 and 1st and 2nd slave stations 3 and 4 are represented by specific expressions. The time differences ts1, ts2, and t0 are already known and times t1, t2, and t3 are measured to obtain the distances l1, l2, and l3. Thus, the band of sent signals may be narrow because the master station 1 and mobile station 2 send the signals which are amplitude-modulated with a sine wave. Further, the master station 1 and slave stations 3 and 4 measure the time differences with signals obtained by multiplying a measurement signal and a delayed measurement signal, so the time differences are measured with high accuracy and the position accuracy of the mobile station 2 which is determined by the time differences can be improved.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to use Xie Dingbo's position measurement system to determine the position of a mobile station, narrow the signal band, and increase position accuracy. The mobile station receives the amplitude modulated signal of the measurement signal and transmits the amplitude modulation signal of the dispatch measurement signal delayed by a predetermined time, and the master station receives the amplitude modulation signal of the measurement signal. 1 modulation signal is received, the delayed measurement signal is demodulated, the time difference between the signal obtained by multiplying the measurement signal and the signal obtained by multiplying the delayed i11 measurement signal related to II is measured, and multiple slave stations demodulate the measurement signal and the delay measurement signal. Receive the amplitude modulation signal of the delay measurement signal, modulate the measurement signal and the delay measurement signal by 1a, measure the time difference of 4 times between the signal obtained by multiplying the demodulated measurement signal and the signal obtained by multiplying the delay measurement signal by 5tab, The mobile station is configured to calculate the distance to the mobile station based on the time IIl difference in the II8 and each of the plurality of slave stations, and determine the position of the mobile station.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a positioning system, and more particularly, to a positioning system for determining the position of a mobile station.

Conventionally, the position of a mobile station such as a single person in a car is measuredff
There is a measurement system. Such a system does not grow in scale, and the location W! A high level of accuracy is required.

(Prior Art) As a conventional position measurement system, (1) a moving object is equipped with a GPS receiver that receives position signals from the vIJ star using GPS (Global Positioning System), and at least three A method of measuring the position using the position information signals of several GPS satellites;
A method of measuring the position at the intersection of the directions of a moving object from two fixed stations. ■ The moving object receives pulse signals from at least three Loran stations or Detsuka stations, and the pulse signals from each station are measured using the same phase difference. There is a method of measuring the position by hyperbolic navigation to find the distance between.

[Problem to be solved by the invention]

Conventional satellite methods require multiple satellites, making the entire system large-scale and costly.

Method (2) has four problems: the M1a degree worsens as the distance between the moving object and the fixed station increases, depending on the accuracy of the direction finder.

In method (2), if an attempt is made to improve the positional accuracy, the edge of the pulse must be steep, and the positional accuracy is limited by the bandwidth of the pulse signal to be transmitted.

The present invention has been made in view of the above points, and an object of the present invention is to provide a position measurement system with a narrow signal band and high position accuracy.

[Means to solve the problem]

FIG. 1 shows a diagram of the principle of the system of the present invention.

In the figure, a master station 1 transmits an amplitude modulated signal of a sine wave measurement signal.

The mobile station 2 receives the amplitude modulation signal of the measurement signal and performs a predetermined II
The amplitude variation signal of the delayed delay measurement signal is transmitted.

The master station 1 receives the amplitude modulation signal of the delay measurement signal, demodulates the delay measurement signal, and measures the time difference between the signal obtained by multiplying the measurement signal and the signal obtained by multiplying the delayed measurement signal.

1st. The second slave station 3.4 receives the amplitude modulation signal of the measurement signal and the delay measurement signal, and converts the measurement signal and the delay measurement signal into one signal.
! The time difference between the signal obtained by multiplying the leaked and demodulated measurement signal and the signal obtained by multiplying the delayed measurement signal obtained by W correction is measured four times.

The position of the mobile station 2 is determined by calculating distances t'l+ and lz+L3 from each of the master station 1 and the plurality of slave stations 3.4 to the mobile station 82 based on the time differences obtained from each of the master station 1 and the plurality of slave stations 3.4.

[Effect]

In the present invention, the master station 1. Since the mobile unit 82 transmits a signal whose amplitude is modulated with a sine wave, the band of the transmission signal can be narrow. Since the second slave stations 3 and 4 each measure the time difference using a signal obtained by multiplying the measurement signal and the delay measurement signal, the time difference can be measured to a high degree, and the accuracy of the position of the mobile station 2 determined from the time difference is improved.

(Example) FIG. 2 shows a block diagram of one embodiment of the master station.

In the figure, llll11 section 20 is a highly stable reference signal oscillator 2.
A predetermined frequency (for example, 10KH
z), and this measurement signal is supplied to an AM modulator (MOD) 21 and a transmitter 29, and is also supplied to an AM modulator (MOD) 21 and a transmitter 29.
11 section 20 supplies a switching signal synchronized with the measurement signal to a switch (SW) 22.

The AM modulator 21 is supplied with a divided signal with a frequency of, for example, 10 MHz, which is obtained by dividing the highly stable reference signal of frequency 01 outputted from the oscillator 24 by a frequency division Ia 25, and this frequency divided signal is amplitude-modified by the measurement signal II ( AM modulation) and mixer (M
IX) 26. The mixer 26 receives AM from the reference signal.
! ! [Add signal! s mixing and frequency conversion, and the obtained high frequency signal of frequency f1 in the LIHF or VHF band has unnecessary frequency components removed by a bandpass filter 27, is amplified by an amplifier 28, and is supplied to the switch 22. The switch 22 connects the amplifier 28 to the antenna 30 when a switching signal is supplied, and the high frequency signal is transmitted from the antenna 30.

The switch 22 connects the antenna 30 to the bandpass filter 31 when no switching signal is supplied, and the received high frequency signal received by the antenna 30 at this time is passed through the bandpass filter 31.
．． It is supplied to a mixer 33 through an amplifier 32, where the reference signal is reduced and mixed and converted to a frequency of 10 MHz.
AMIII device (OEM) 3 through bandpass filter 34
5.

Frequency 10KHz obtained by demodulating with AM demodulator 35
The delay measurement signal is multiplied by m by a transmitter 37, shaped into a waveform by a waveform shaping circuit 38, and then supplied to the time determining section 23. The time measurement unit 23 uses the signal obtained by multiplying the measurement signal from the control unit 23 by m by the transmitter 29 as a reference, and uses the time difference a (I! as indicated by the 31i1(A) GC) with the delay measurement signal from the mobile station 2 as a reference.
0 difference j+) is measured and supplied to the position calculation section 39.

The position calculation unit 39 is the first. The time difference t2 shown in FIGS. 3(8) and 3(C) is transmitted from the second slave station via the terminal 40. t= is supplied, and this time difference jl * j2 * t3 is calculated as the distance 1111i+, tz, t between the master station, each slave station, and the mobile station, respectively.
The position of the mobile station is determined by calculating the intersection of circles having a distance of tllt2°L3 centered on the parent bird and the 1st and 2nd slave stations.

FIG. 4 shows a block diagram of one embodiment of a mobile station.

In the figure, a high frequency signal from a master station received by an antenna 42 is supplied from a switch 43 to an amplifier 44, where it is amplified, and a mixer 45 delimits and mixes it with a local oscillation signal from a local oscillator 46 to generate an intermediate frequency signal. It is considered a signal. This intermediate frequency signal is supplied to the AMtlXll unit 48 and the sub-section 20 of the master station
The output measurement signal is demodulated and supplied to the control section 49. The control unit 49 switches the switch 43 for a predetermined period of time after receiving the measurement signal to use the antenna 42 for transmission.

Further, the intermediate frequency signal is delayed by #l1ijo (for example, 300 μsec) as shown in FIG. 3(D) in the delay circuit 51, and then supplied to the mixer 52, where it is added and mixed with the local oscillation signal and measured to be transmitted from the master station. It is assumed to be a high frequency signal having the same frequency as the signal (ie, an AM modulated signal of the delay measurement signal). This high frequency signal is transmitted from the antenna 42 via a bandpass filter 53, an amplifier 54, and a switch 43.

FIG. 5 shows a block diagram of an embodiment of the slave station.
High frequency signals from the master station and mobile station received by the antenna are passed through a bandpass filter 61. It is supplied to a mixer 63 via an amplifier 62, where it is subtractively mixed with a highly stable reference signal of frequency 01 outputted from an oscillator 64, converted to a frequency of 10MH2, and then passed through a bandpass filter 65 to a band tiIIj! AM after being
It is supplied to the tl adjuster 66. AMv! JI device 66u frequency 10 KHz (7) Perform IIEI on the measurement signal from the master station and the delay measurement signal from the mobile station. The measurement signal and the delay measurement signal are multiplied by m in a transmitter 67, and are waveform-shaped in a waveform shaping circuit 68, and then are
! 13'#J l! 1571.

笾IIl! After receiving the measurement signal, the I71 enters a standby state, has a time measurement section 69 measure the time difference with the delay measurement signal, and supplies it to the master station from the terminal 72. Also 118fFIi
The reference oscillator of the measuring section 69 is the stable oscillator 64 and the branching unit 7.
The signal frequency-divided by 0 is sufficient for the direction 11. 1st.
Each of the second slave stations has B[difference tl.

12 each and supply it to IIII.

Here, as shown in FIG. 3, the distance between the master station and the first slave station causes a difference ts1 of 1 m at the known time, and the distance between the master station and the second slave station causes the difference ts1 at the known time. ! When 1 difference ts2 occurs, the distances 1t+, tz, and ti from each of the master station, first slave station, and second slave station to the mobile station are calculated using the following formula % rIWR difference tS1. t, 2. to is known, and the time difference i1 a t2- 'j3 is measured to find the distance melt +
*t21L3 can be obtained.

In this way, since the iI station and the station ei transmit a signal whose amplitude is modulated with a sine wave, the band of the transmission signal can be narrow. Also, 11 stations and 1st station. Since each of the second slave stations measures the relative rIJ difference using a signal obtained by multiplying the measurement signal and the delay measurement signal, the IIn difference can be measured with high accuracy, and the position accuracy of the mobile station 2 determined from the time difference is improved. Furthermore, the system can be constructed on a relatively small scale, consisting of a master station, a mobile station, and at least two slave stations, and the cost does not increase.

In addition, if three or more slave stations are installed, the number of mobile stations is 11! Accuracy can be increased. In addition, when there are multiple mobile stations, each mobile station has a fixed delay time of 1. A mobile station can be identified by making the numbers different.

〔Effect of the invention〕

As described above, according to the position measuring system of the present invention, the band of the signal to be transmitted can be narrow, the position accuracy can be improved, and the system scale can be small, making it extremely useful in practice.

[Brief explanation of drawings]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a block diagram of an embodiment of the rA station, Fig. 3 is a diagram showing the time sequence of the system of the present invention, and Fig. 4 is a diagram of an embodiment of the mobile station. Block Diagram FIG. 5 is a block diagram of one embodiment of the slave station. In the diagram, 1 is! 1 station, 2 is a mobile station, and 3.4 is a slave station. Patent Applicant: Fujitsu Moku Invention Co., Ltd./) Yokohama Figure 1 = t = m Strike 4 Munname 1 Blade Figure 3

Claims (1)

[Claims] A master station (1) transmits an amplitude modulated signal of a sine wave measurement signal, a mobile station (2) receives the amplitude modulated signal of the measurement signal, and generates a delayed measurement signal delayed by a predetermined time. transmitting an amplitude modulation signal, receiving the amplitude modulation signal of the delay measurement signal at the master station (1) and demodulating the delay measurement signal, and generating a signal obtained by multiplying the measurement signal and a signal obtained by multiplying the demodulated delay measurement signal. A plurality of slave stations (3, 4) receive the amplitude modulation signal of the measurement signal and the delay measurement signal, demodulate the measurement signal and the delay measurement signal, and generate a signal obtained by multiplying the demodulated measurement signal. The time difference between the demodulated delay measurement signal and the multiplied signal is measured, and the distance to the mobile station (2) is calculated based on the time difference at each of the normal station (1) and the plurality of slave stations (3, 4). 2) A position measuring system characterized by determining the position.