JPS62119476A - Position measuring system - Google Patents

Abstract

PURPOSE:To enable a position to be accurately measured without such a complex processing as a lane discrimination or the like by using pseudo noise signs (PN signs) composed of digital codes as a medium for measuring the arrival time of waves. CONSTITUTION:Waves modulated by pseudo noise signs are transmitted from a master station M to slave stations S1-Sn, receiving the waves, produce pseudo noise signs synchronizing those in the received waves at least at an initial stage and transmit the waves modulated by the pseudo noise signs to the measuring station O. The measuring station O obtains the differences in the arrival time of the waves from the master station M from the pseudo noise signals involved in the respective waves and, based thereon, calculates the position of the measuring station O by a hyperbolic system.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a position measurement method, and in particular, a method using a radio wave Kv@ with a pseudo-noise signal as a measurement medium. 9. The distance to fixed points (three or more) can be measured, and the position of the variable point can be determined from the difference in distance to two fixed points. That is, 2
As is well known, the locus of a point with a constant difference in distance is a hyperbola, so as shown in Figure 6, the distances from the measurement point X to the fixed points A, B, and C are measured. , fixed point A.

The difference in distance at Bt is constant (at that time, the measured fluctuation point
A point drawn by a point with a constant value determined by the position of lIMB)
The intersection point between the hyperbola (b) drawn by the point where the difference in distance between the fixed points A and C is one foot (a constant value determined by the position of the measured fluctuation point X at that time) is the position of the measured fluctuation point X. Become. The method of calculating the position of the measured fluctuation point in this manner is known as the hyperbolic method.

(Prior Art) The position measurement system using the above hyperbolic method (hereinafter referred to as a positioning system. Hereinafter, "position measurement" is expressed as "one position") has a plurality of known installation points (
This corresponds to the fixed point. ) and a slave station (the master station is the t-1 station and there are two or more slave stations).
and the measurement station installed at the measured point (corresponding to the fluctuation point), and the distance between the main station, valley slave station, and measurement station is calculated from the propagation time of the radio wave. A system for positioning the above-mentioned point to be measured is known.

This positioning system uses a pulse time difference method that uses a nollus signal as the measurement medium and calculates the distance by determining the time difference between the transmission and reception of the pulse signal, and a sine wave signal as the measurement medium. A sine wave phase difference method is well known in which the distance is calculated from the phase difference between the transmitted signal and the received signal.

(Problems to be Solved by the Invention) In the above-mentioned conventional method, the arm-to-shoulder time difference method cannot significantly improve measurement accuracy because waveform distortion occurs in the pulse signal due to radio wave propagation. If the number of slave stations is increased in order to increase the speed, the measurement cycle becomes longer because each slave station requires a different 9-cycle transmission cycle, which is extremely inconvenient for measuring positions that change over time, for example. be.

In addition, in the sine wave phase difference method, when widening the measurement range, it is necessary to set the period of the sine wave signal to be long (because the same phase point of the transmitted wave and the received wave appears every period of the sine wave signal). , the range that can be measured without performing lane identification, which will be described later, is the range equivalent to one cycle of the sine wave signal.)
Increasing the period of the sine wave signal lowers the measured product. Therefore, in order to maintain a high degree of measurement accuracy, it is necessary to shorten the period of the sine wave signal and to use a sine wave signal with a long period for measurement when the time difference between the transmitted wave and the received wave exceeds one period of the sine wave signal. Lane identification processing using wave signals is required, and two or more types of signals are required for the side legs, making it necessary to control switching of measurement ranges, etc., making processing extremely difficult.
1.It becomes miscellaneous.

(Objective of the Invention) The present invention is proposed to solve the above-mentioned conventional problems, and is to provide a position measurement method that can maintain a high level of measurement accuracy and that does not require lane identification. With the goal.

(Summary of the Invention) For the above purpose, the present invention provides a main station installed at a fixed point, a slave station installed at each of a plurality of fixed points where the positional relationship between the main station and the installation point is known, A system is configured with a measurement station installed at a measured point (variation point), and the main station transmits radio waves modulated with pseudo noise codes to the slave station and the measurement station, and the slave station receives the radio waves and transmits them into the received radio wave. Generates a pseudo-noise code that is synchronized at least in its starting period with the pseudo-noise code of The time difference is determined based on the pseudo noise signal contained in each radio wave, and based on this, the position of the measuring station is calculated using the hyperbolic method.

(Configuration of the embodiment) Figures 1 to 4 are diagrams explaining the configuration of the embodiment of the present invention. Figure 1 is a system configuration diagram, and Figure 2 is a main station professional diagram. FIG. 3 is a block diagram of the slave station, and FIG. 4 is a professional diagram of the Fi side foot station.

As shown in FIG. 1, the positioning system according to the embodiment of the present invention is composed of one main station M, a plurality of slave stations S, ~S, and one measurement station O. ~Sn is installed at a known fixed point, and measurement station O is installed at a variable point (positioning point) to be measured. In addition, in the case where there are a plurality of positioning points, the main station M and the slave stations S, to Sn can be shared by the measuring stations placed at each side position. In addition, since it is a measurement station oFi reception-only station, there is no limit to the number of measurement stations that can be installed.
If a PN code is provided, each ship will be able to perform self-positioning. The main station M generates a pseudo-noise code (hereinafter referred to as a PN code) with a digital code structure, as shown in Figure 2. P
N code generator 11, carrier wave generator 12 that generates a carrier wave
, a multiplier 13 that multiplies the PN code from the PN code generator 11 and the carrier wave from the carrier wave generator 12 to generate a high frequency signal modulated by the PN code, and the high frequency signal from the multiplier 13 is power amplified. The antenna 15 transmits a high frequency signal from the power amplifier 14 into the air as a radio wave.

As shown in Fig. 3, slave station S (subscripts 1 to n are omitted when there is no need to distinguish between slave stations) receives radio waves from master station M, and also receives radio waves from its own station. An antenna 21 that sends out into the air, a circulator 22 that branches the transmission path of the outgoing radio waves and the incoming radio waves, and has a passband of the frequency band of the outgoing radio waves of the main station M, and eliminates noise and transmits the incoming radio waves from the main station M. a bandpass filter 23 that only transmits the signal, a local oscillator 24, a mixer 25 that mixes the incident radio wave from the main station M with the signal from the local oscillator 24 and receives the PN code from the main station M, and this mixer DLL (Delay L) for generating a PN code synchronized with the PN code received at 25.
ock Loop) circuit 26, a carrier wave generator 27, a multiplier 28 that multiplies the PN code generated by the DLL circuit 26 and the carrier wave from the carrier wave generator 27 to generate a high frequency signal modulated by the PN code; It is composed of a power amplifier 29 that amplifies the power of the high frequency signal from the multiplier 28 to generate radio waves.

The DLL circuit 26 generates a PN code that has the same arm turn as the PN code generated in the main station M (although it does not necessarily have to be the same pattern, it will be explained as being the same for a while). A generator 261, a multiplier 262 that multiplies the PN code from the PN code generator 261 by the PN code from the mixer 25, and processes the signal from the multiplier 262 by a known correlation synchronization method to generate a PN code. The generation operation of the PN code in the generator 261 is controlled to generate the corresponding P
A PN code synchronizer 263 synchronizes the PN code from the N code generator 261 with the PN code from the mixer 25.

As shown in FIG. 4, the side station O includes a main station receiver plate that receives signals from the main station M, and slave station receivers SR and ~SRn that receive signals from slave stations S and ~Sn, respectively. The antenna 31 and each receiving section receive the radio waves from the main station M and the substation S, respectively.

Output information from SR1 to SRn (time difference measuring device 5 described later)
A computing unit 32 for processing the output data (output data 1 to 5n) is provided in common to each of the receiving units MR, SR, to SRn. Note that the slave station receivers SR (subscripts 1-n are omitted when there is no need to distinguish between the slave station receivers) have the same configuration, and in FIG. 4, the slave station receivers SR
1, its internal configuration is shown.

The main station receiving section and the slave station receiving section SR each have a bandpass filter 33.43, a local oscillator 34.44, a mixer 35.45, and a DLL circuit 36.46 (PN code generators 361, 461, multiplier 362°462, PN
code synchronizers 363, 463), and the functions of each part are the reception section of the slave station S (bandpass filter 23, local oscillator 24, mixer 25, and DLL circuit 26 (PN code generator 261, multiplier 262, PN code synchronizer 261, multiplier 262, code synchronizer 263)
It is the same as each constituent part of (the part consisting of). However, the pass frequency band of the band pass filter 33.43 and the excavation frequency of the local oscillator 34.44 are the main station M and the slave station S, respectively.
It is set corresponding to the frequency of the signal ('α wave) from the

In addition to the above configuration, time difference measuring devices 51 to 5n are provided corresponding to each slave station receiving section SR4 to SRn.
It is connected between the output line of 6 and each output line of the DLL circuit 46 of the valley slave station receivers SR1 to SRn, and is connected between the output line of the DLL circuit 46 of the valley slave station receiving units SR1 to SRn. Calculate the time difference between

(Operation of the embodiment) FIG. 5 is a time chart showing the time relationship of signal transmission and reception in the embodiment of the present invention. The operation of the embodiment having the above configuration will be described below with reference to FIG.

In the main station M shown in FIG. 2, a PN code generator 11
generates a PN code with a digital code structure. This PN code is different from the conventional sine wave signal, and its period T (FIG. 5) can be extremely long, for example, about 1100 k (on the contrary, in the case of a sine wave signal, it is at most 1 kfn).

The PN code sent out from the PN code generator 11 modulates the carrier wave signal (frequency fm) from the carrier wave generator 12 in the multiplier 13, and the high frequency signal thus generated is powered by the power amplifier 14. After being amplified, all median lines 1
5 is emitted as radio waves.

That is, the radio wave sent out from the main station M is a high frequency signal of frequency fm modulated with the above-mentioned PN code.

The radio waves transmitted from the master station M in this manner are received by the slave stations S1 to Sn and the measurement station O.

In the slave station S shown in FIG. 3, the radio waves incident on the antenna 21 are branched by the circulator 22 in the direction of the band-pass filter 23, and the band-pass filter 23 splits only the radio waves (frequency fm) from the main station M. is selected. The radio wave (high frequency signal) from the main station M that has passed through the bandpass filter 25 in this way and the signal from the local oscillator 24 are mixed in the mixer 25, and the mixer 25 is configured to handle the difference between the two signals. The frequency signal is sent to the DLL circuit 26. Of course, the signal with this difference in frequency is
Contains the PN code generated within.

In the DLL circuit 26, the PN code generator 261 generates a PN code with the same bit arrangement as the PN code generator 11 of the main station M (although it does not necessarily have to be the same, for the time being it will be explained as being the same). This PN code and the signal from the mixer 25 are multiplied by a multiplier 262, and the result is correlated by a PN code synchronizer 263. Based on the correlation, the PN code generator 261 By controlling the PN code generation operation (correlation synchronization method), the DLL circuit 26 outputs a PN code synchronized with the PN code in the signal output from the mixer 25.

The PN code output from the DLL circuit 26 is sent to a multiplier 28 as a carrier wave signal (frequency fm
), and the high frequency signal generated in this way is power amplified by a power amplifier 29, and then branched by a circulator 22 in the direction of the air Iw 21.
is emitted as radio waves. Note that the frequency of the radio waves from the slave station S has different values (f81
．． fs2,...n,? ”, n) (It is not necessarily necessary to set different values, but for the time being, we will explain that they are different from each other.) As described above, the values are sent from each slave station S, ~8. Each radio wave is received at measurement station O.

At the measurement station 0 shown in FIG. 4, the radio waves from the main station M and the slave stations S, ~Sn, which are incident on the antenna 31, are received by the single station receiving section and the slave station receiving sections SR4 to SRn, respectively. , the main station receiving section and each slave station receiving section SR, ~SR
n outputs a PN code synchronized with the PN code included in each received radio wave. The PN code output operation of the main station receiving section forward and each of the slave station receiving sections SR, -SRn is similar to the PN code output operation of the DLL circuit 26 in the operation of the slave station S.

The radio wave reception times at the master station receiving section MR and each slave station receiving section SR1 to SRn are different from each other because the distances between the main station M and each slave station S1 to Sn and the measurement station 0 are different. Based on the PN code included in each radio wave, the time difference measuring devices 51 to 5n measure the arrival time of the radio wave from the master station M and the arrival time of the radio waves from each slave station S, ~Sn. Understand by the difference between The arrival time difference information of each radio wave obtained by the time difference measuring devices 51 to 5n is input to the calculator 32, and based on this information, the position of the measuring station 0, that is, the position of the positioning fluctuation point is calculated.

The master station M sends out a radio wave, and after each slave station S1 to Sn receives the radio wave, each slave station S, ~Sn sends out a radio wave, and receives the 'radio wave from the master station M and each slave station S, ~Sn. As is clear from the above explanation, the time relationship until the measurement station 0 receives the signals has the same reference point (at the time of transmitting the radio waves from the main station M) due to the synchronization effect of the PN code included in each radio wave.

Now, as shown in FIG. 1, the time taken for the radio waves sent by the master station M to reach the measuring station 0 is tm1 The time taken for the radio waves sent from the master station M to reach the valley slave stations S, ~Sn is t, ~L
n sAssuming that the time taken for the radio waves sent by each slave station S, ~8 to reach the measurement station O is t81~t8n, after the master station M sends out the radio wave, the measurement station 0 receives the signals from the slave stations S, ~S. The time tm81 to tmsn until receiving one wave is clear from FIG. 5 (however, in FIG. 5, two slave stations 81 * 8
Only 2 is shown. )% The following is the standard.

tma1== t1+t111 tm82:t2+ts2 tman''+tsn In other words, at measurement station 0, the main station receiving section outputs the PN code at time t after the main station M sends out the PN code.
tm8.m after the master station M sends out the PN code, and each slave station receiving section SR, to SR outputs the PN code at a time tm8. After ~tffllIn.

The time difference measuring devices 51 to 5n measure the PN code reception time at the main station receiving section and the P at each of the slave station receiving sections SR, -SRn.
Since the difference with the N code reception time is calculated, each output Δ, ~Δ1 is Δ1” tmllll-tm=(tm1-tm)
"t1Δ2""tmll□-1m=(1,2-1
m)+12Δ1=tman-tm=(tlln-trn
)+tn.

By the way, the main station M! : Since the positional relationship with each slave station S, ~Sn is fixed, the values of the above-mentioned times t, ~tn are known. Therefore, in the computing unit 32, each time difference measuring device 51
~5n output Δ, ~Δ. From each above-mentioned time t, ~
By subtracting tn (by subtracting tn, the difference between the radio wave arrival time from the main station M and the radio wave arrival time from each slave station S1 to Sn at measuring station 0 can be obtained, and this radio wave arrival time difference is calculated by adding the speed of light (approximately 3
By multiplying by X 10 m/see ), the difference in distance between the main station M and each slave station S, ~Sn as seen from the measurement station 0 can be calculated. Therefore, positioning using the hyperbolic method described above becomes possible.

That is, when applied to FIG. 6, the main station M, slave station S, and S2 are installed at the fixed points A, B, and C, respectively, and the measuring station O is installed at the measuring point X (however,
When there are two slave stations) and 0) are (tsl tm) xc
The line ←) indicates (t82-tm)×C (where C is the speed of light).

The lines (a) and (b) actually have a width depending on the measurement deviation, and their intersection point X (point to be measured) has an area based on the measurement deviation. In order to improve the positioning accuracy, it is possible to reduce the above area, but for this purpose, the slave station S
The number of units installed may be increased to perform calculations based on a large number of hyperbolic functions.

In the above embodiment, P included in the radio waves transmitted from the main station M
N code and each P included in the transmitted radio waves from slave stations S1 to Sn
It is assumed that all N codes have the same number of turns, that is, the same bit configuration, but as is clear from FIG.
The codes only need to have their starting times based on the same time reference. Therefore, it is sufficient for each PN code to be synchronized at least at its starting point, and the bit configurations do not necessarily have to be the same.

In addition, in the embodiment, the frequencies of the radio waves transmitted by the slave stations S and ~Sn are different from each other, but if the bit configuration of each PN code is made different from each other as described above, the measurement station 0 has a PN
Since the transmitting slave station of the received radio wave can be determined from the bit structure of the code, it is also possible to set the frequency to be the same as the frequency of the transmitting radio wave of each slave station S, ~S.

(Effects of the Invention) As explained in detail above, in the present invention, a PN code is used as a medium for measuring the arrival time of radio waves, and the PN code has a large number of pits. Since the cycle can be set extremely long while keeping the bit length short, highly accurate positioning is possible without complicated processing such as lane identification (compared to the conventional sine wave phase difference method). ), high-precision positioning can be achieved by increasing the code speed of the PN code, and since the correlation synchronization method can be adopted by using the PN code, high reliability can be maintained against interference such as noise (foreign radio waves, etc.) , the measurement cycle does not become longer even if the number of slave stations is increased in order to improve positioning accuracy (compared to the conventional pulse time difference method), and the present invention has extremely remarkable effects. .

[Brief explanation of drawings]

1 to 5 are detailed explanations of the present invention.
The figure is a system configuration diagram, Figure 2 is a block diagram of the main station, and Figure 3 is a block diagram of the main station.
The figure is a block diagram of the slave station, Figure 4 is a block diagram of the measuring station,
FIG. 5 is a time chart showing the time relationship of signal transmission and reception, and FIG. 6 is a diagram showing the principle of the hyperbolic positioning method. (Main symbols) M...Main station, 5 (81~Sn)...Slave station, 0...Measuring station, Dish...Main station receiving section,
SR1 to SRn...Slave station receiving unit, 11, 261, 361, 461...PN code generator, 15.21.31...Antenna, 26.36
．． 46...DI, L circuit, 263, 363, 46
3... PN code synchronizer, 51-5n... time difference measuring device. Figure 2

Claims (1)

[Claims] A master station installed at a fixed point, slave stations installed at multiple fixed points where the positional relationship between the master station and the installation point is known, and a measurement station installed at a variable point where position measurement is to be performed. The master station transmits a radio wave modulated with a pseudo-noise code, and each of the slave stations receives the radio wave from the master station and generates a pseudo-noise whose start period is at least synchronized with the pseudo-noise code in the received radio wave. A code is generated and a radio wave modulated with the pseudo noise code is transmitted, and the measuring station calculates the arrival time difference between the radio wave from the master station and the radio waves from each of the slave stations using the pseudo noise code included in each radio wave. A position measurement method in which the position of the measurement station is calculated based on the noise code and the arrival time difference is detected.