JPS60173485A - Position measurement system - Google Patents

Abstract

PURPOSE:To measure the position of a moving body with high precision by proper position measurement systems by estimating the transmission time of an acoustic wave, light, or electromagnetic wave from the moving body by a hyperboloid position measurement system, and then employing a spherical position measurement system. CONSTITUTION:Sensors S1-Sn receive the acoustic wave, light, or electric wave, etc., from the moving body 1 and a moving body position calculation system 2 calculates the position of the moving body 1 by the hyperboloid position measurement system. Then, the transmission time of the acoustic wave, light, or electromagnetic wave from the moving body 1 is estimated from said calculation result, and this is used by the system 2 to calculate the position of the moving body 1 by the spherical position measurement system. Therefore, even when the transmission time of the acoustic wave, light, or electromagnetic wave from the moving body is known, the position measurement arithmetic is carried out by the spherical position measurement system and the position of the moving body is measured with high precision by the proper distance measurement systems according to the state.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention uses a plurality of sensors to receive sound waves, electromagnetic waves, etc. from a moving object that emits energy radiation such as sound, light (heat), or electromagnetic energy. The present invention relates to a positioning method for accurately determining the position of the moving body based on the reception time at the sensor.

[Background of the invention]

Conventionally, as positioning methods, a hyperboloid positioning method and a spherical positioning method are known.

Hyperboloid positioning method uses sound waves between multiple sensors.

Utilizing the difference in reception time of light (heat) or electromagnetic waves,
In this method, the location of the moving object is determined by the intersection of multiple hyperboloids in space, where the reception time difference is constant. In this method, it is difficult to accurately determine whether the calculated location of the moving object is at the time of the visit. There are problems in that it is difficult to know and it takes a long time to process the position calculation.

The spherical positioning method is based on the assumption that the transmission time of sound waves, light (heat), or electromagnetic waves from a moving object is known, and the propagation time of sound waves or electromagnetic waves from each sensor is the same. This is a method in which a spherical surface is drawn and the positions of the moving object are determined by points on multiple spherical surfaces. Although this method shortens the calculation time, there is another problem in that it cannot be used unless the time of transmission of the sound waves or electromagnetic waves from the moving body is known.

However, due to the geometric positional relationship between the moving object and the sensor group,
Either of the above two lateral methods will provide good position estimation accuracy, but as mentioned above, both methods have certain constraints, so select one of the positioning methods according to these constraints. The reality is that we have no choice but to do so. this is,
This is not a problem in systems with few propagation error factors such as acoustic waves or electromagnetic waves, but in systems with many propagation error factors, it becomes a serious problem in terms of accuracy.

[Purpose of the invention]

The present invention has been developed in view of the above circumstances, and its purpose is to solve the above-mentioned problems in conventional positioning methods17 and to provide a highly accurate positioning method.

[Outline of the invention]

The main point of the present invention is to use the hyperboloid positioning method to detect sound waves of a moving object.
By estimating the transmission time of light (heat) or electromagnetic waves, etc., and using this to enable the use of the spherical positioning method, it is possible to use the bilateral method.Furthermore, the position estimation error of the bilateral method can be estimated. The point is that it is possible to select which method to use.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a configuration diagram of a radio wave positioning system showing an embodiment of the present invention. In the figure, 1 is a moving body, Sl + S2
+...S represents a sensor for receiving radio waves from the mobile object 1, and 2 represents a mobile object position calculation system. The mobile object position calculation system 2 includes a storage device 3. It consists of a processing device 4 and a display device ff5. Also, do, d2119.10. ,.

indicates the distance between the moving body l and each sensor.

Radio waves emitted from the mobile body 1 are received at a station Sl that is a distance do away from the mobile body 1. The sensor S+ receives the radio wave at the time 1. is transmitted to the mobile body position calculation system 2. Above reception time 1. If the propagation speed of radio waves is V, then the following equations are satisfied: t + =d + /V, +T+n + . Here, T is the transmission time of the radio wave from the mobile object 1, and nI is noise due to various factors.

It is assumed that the signal transmitted from the moving object 1 is a pulse-like signal, as shown in FIG. 2, and the time interval To between each pulse is constant. Furthermore, it is assumed that the time interval To is sufficiently long compared to the radio wave propagation time.

In the mobile object position calculation system 2, human data is
The data is temporarily stored in the storage device 3, the processing device 4 calculates the position of the moving object, and the calculation result is output to the display device 5. Here, the processing device 4 has a sensor position (X+, 3'l) measured in advance.
, z+) are stored in a usable manner.

By the way, in the hyperboloid positioning method, if the position of the moving object is (x, y, z), t+-11=u (X X+)'+(y)'+)'+(
Z Zl)2■.

” (Xx+)”±(y Vj)2+(z”+)2+n
+J■6 A nonlinear equation is obtained. From this, by the method of least squares, we obtain -''n ex4 unquestioned], 2+(z-2j)2)2)■.

It can be seen that (X, y, z) becomes. In addition, in the spherical positioning method, if it is assumed that the transmission time T is known, n equations such as .

Hereinafter, a method of estimating the transmission time of the mobile object 1 from the hyperboloid positioning method, which is the first point of the present invention, will be explained.

Let T'' be the time when a certain pulse is transmitted.Using the reception time 1.-1. of this pulse, the position (X+y+z) of the p mobile body 1 can be calculated by the hyperboloid positioning method. The time T can be estimated using information from n sensors as . However, the estimated value of T for a single pulse may be significantly different from the true value T due to various error factors. .By the way, the Nogurus time interval is T
o, so that the no-pulse transmission time after T1 can be determined by the heat. In other words, the pulse transmission time T (m) of the mth pulse from T is m From the mobile object position estimation data of the pulse, ΔT('') = T('') + mT.

It can be stopped. From this, T is calculated as Δl m A meal T=−[Σ(T (i) 1Tol) In l=0. The relationship between the error in estimating the timing of T at the time of transmission and the number of times T is estimated using pulses is qualitatively shown in FIG. 3.

That is, the number of times M at which the transmission time estimation error becomes sufficiently small is set, and the estimated value of T after M times is used. In this case, the pulse transmission time after T can be estimated as T (J = T + k T+1. This makes it possible to use the spherical positioning method.

Next, the estimated prediction error index (Geome
tric Delution of Precision
n, hereinafter referred to as "GDOP") will be explained. Regarding this GDOP, the satellite selection method in satellite navigation,
For example, Murata: Global positioning satellite system NAV STA
几/GPS, Measurement and Control, Vol. 21, p. 247 (1982)
, or H, B, Lee: A Novel
procedure for Assessing
Be Accuracy of Hyperbolic
MulBIateration Systems.

I E E E Transac t 1ons O'n
Aerospace and Electron7cs
Systems, VOI, AES 11. AI
(1975).

The above GDOP gives the position estimation error as a function of the geometric relationship between the moving object and the sensor and the error, and in the case of the spherical positioning method, P k = (HTkI (, -: Hb) - It is given by the sum of squares of the diagonal elements of the matrix given by ', where:
Rh is given by an nxn matrix, and σI2 indicates the variance of the error in the reception time measurement of sensor i. Further, Hh is a value determined from the geometrical relationship between the sensor and the moving object, which is given by . Here, 11' is a unit direction vector from the moving body to the sensor.

In addition, in the case of the hyperboloid positioning method, the above ()DOP is PkH
=((LHk)(L RkL)-'(LHk))-'
3, which is the sum of squares of the diagonal elements of the matrix given by , where Hk and Rk are the same as in the spherical positioning method, but L is given by the matrix of . A matrix caused by the combination of sensors in the LH hyperboloid positioning method. In this case, from the time observation equation of sensor i, sensor! It is assumed that the time observation equation of +1 is subtracted to create a hyperboloid regarding sensor i and sensor i+1.

Here, GD OP when using the spherical positioning method is Gs
, Gl when using the hyperboloid positioning method) If OP is GR, when Gg > Gn, the hyperboloid positioning method is used;
When GH>Gs, it is desirable to use the spherical positioning method. The processing described above can be executed by the processing device 4 in the mobile body position calculation system τ system 2. A flowchart of this process is shown in FIG.

The process shown in FIG. 4 is a process that is repeatedly activated at certain time intervals. First, GDOP is calculated for the hyperboloid positioning method and the spherical positioning method. Gn) In the case of Gs, execute the hyperboloid positioning method and find the moving object position (X+y+z). Furthermore, the radio wave transmission time T from the mobile object is estimated.

Furthermore, if Gs>On, it is checked whether the spherical positioning method can be executed. That is, it is checked whether the estimated value of T obtained in the above process can be used, and if it is usable, the spherical positioning method is executed. If the estimated value of T is not available, a hyperboloid positioning method will be implemented.

In addition, in the estimation process of the transmission time T of the radio wave,
It is preferable to set a flag indicating that the estimated value of T is usable after the estimation process of T is executed a predetermined number of times.

In the above embodiment, which of the hyperboloid positioning method and the spherical positioning method is selected is determined directly by GDOP, but the present invention is not limited to this.
It goes without saying that this does not preclude the use of other appropriate indicators. In addition, in the above embodiments, the present invention is
Although an example in which the present invention is applied to a radio wave side system is shown, it is possible to use sound waves, light, etc. instead of radio waves, as described above.

Through the processing described above, the estimation error of the moving object position is divided into the error due to the hyperboloid positioning method and the error due to the spherical lateral positioning method.
It will be approximately equal to the smaller one.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to estimate the transmission time of sound waves, light (heat), electromagnetic waves, etc. from a moving object using the hyperboloid positioning method, and use this to make it possible to use the spherical positioning method. This makes it possible to use both positioning methods, and furthermore, it is possible to select which method should be used by estimating the position estimation error of both methods, making it possible to achieve a highly accurate positioning method. It is effective.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a radio positioning system showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a signal transmitted from a moving object, FIG. 3 is a graph showing a transmission time estimation error curve, and FIG. 4
The figure is a flowchart of lateral position processing. 1... Mobile object, 2... Mobile object position calculation system, 3
...Storage device, 4.Processing device, 5.Display device, SH-S, ...Sensor. Figure 2 Figure 3 Figure 4- Old

Claims (1)

[Claims] 1. A plurality of sensors receive sound waves, light, or electromagnetic waves from a moving body that emits sound waves, light, or electromagnetic waves, and based on the difference in reception time, the sound waves, light, or electromagnetic waves of the mobile body are determined. In a positioning system that determines a position, or a positioning system that receives sound waves, light, or electromagnetic waves from multiple moving objects with one sensor and determines the position of the sensor based on the difference in reception time, a hyperboloid A positioning method characterized in that the transmission time of the sound wave, light, or electromagnetic wave of the mobile body is estimated by a positioning method, and a spherical positioning method can also be used. 2. A positioning system that receives sound waves or electromagnetic waves from a mobile body that emits sound waves, light, or electromagnetic waves using a plurality of sensors, and determines the position of the mobile body based on the difference in the reception times; , a positioning system in which a single sensor receives sound waves, light, or electromagnetic waves from a plurality of moving objects, and determines the position of the sensor based on the difference in reception time, in which the moving objects are determined by a hyperboloid positioning method. The present invention is characterized by estimating the transmission time of a sound wave, light, or electromagnetic wave, and calculating the position estimation error between using a hyperboloid positioning method and using a spherical positioning method, and determining the positioning method to be selected. Positioning method.