RU2524482C1 - Method for single-position radar location of mobile objects on road network - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method comprises measuring the angle of arrival of an electromagnetic wave (bearing) α_meas(t) from an object from one measuring point, the position of which is known, wherein signals emitted by the object include an identification code thereof; while emitting the signal, measuring at the object, the velocity ν_meas of said signal along a road network element; encoding a signal that is proportional to the measured velocity and transmitting the obtained code over a radio link to the measuring point where, after receiving and decoding, a value of the measured velocity is obtained; after a time Δt, re-measuring the bearing α_meas(t+Δt), with identification thereof from the identification code of the object; determining the length of the path Δe=Δtν_meas traversed over time Δt; based on the measured bearing α_meas(t) and parametric models of the bearing αⁱ(e), $$i=\overline{\mathrm{1,}I},$$

given in the function of a natural parameter, for each road network element, determining the values of the natural parameter $$e_i^{*},$$

$$i=\overline{\mathrm{1,}I},$$

corresponding to points of intersection of the position line for the measured bearing α_meas(t) and the road network element; for each of said elements, determining bearing candidates $${\alpha }^i\left(e_i^{*}+\Delta e\right),$$

$$i=\overline{\mathrm{1,}I},$$

corresponding to movement of the object by a distance Δe, and determining the number i* of road network elements on which the object is located based on the condition of minimal mismatch between said candidates and the measured bearing α_meas(t+Δt); determining coordinates of the object as coordinates of the point of intersection of the position line corresponding to the measured bearing (α_meas(t) or α_meas(t+Δt)) and the i*-th road network element.

EFFECT: unique determination of a mobile object associated with a road network.

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Description

The object of the invention is a method of single-position radar of moving objects - radio signal sources on the road network. The proposed method relates to the field of radar and radio navigation, since a class of tasks of this type underlies the determination of estimates of the location of objects.

A known method of radar objects - sources of a radio signal on the plane [1]. Its disadvantage is the need to measure the angles of arrival of electromagnetic waves (bearings) from two spaced measuring points, the position of which is known. This method does not provide an unambiguous determination of the location estimate in the event of failure of one of the direction finders.

There is also a known method of radar objects - sources of a radio signal on the plane [2], which consists in measuring the angles of arrival of electromagnetic waves (bearings) from two spatially spaced measuring points, the position of which is known, determining the coordinates of the location of the object as the point of intersection of the position lines corresponding to the measured bearings. It also focuses on the mandatory use of two spaced direction-finding radios and loses its functionality when one of them fails.

The purpose of the invention: to enable unambiguous location of a moving object tied to a road network (a priori description of which is set, for example, in the form of an electronic map), based on measurements at one measuring point:

- bearing of the object by its electromagnetic radiation at time t;

- bearing of an object by its electromagnetic radiation at a time (t + Δt);

autonomous measurement of the speed of the object along the road at time t; coding a signal proportional to the measured speed; transmitting the received code over the radio data channel to the measuring point, where, after receiving and decoding, the measured speed value is obtained.

The invention consists in the following. Each element of the road network is described by a parametric dependence (Figure 1)

$$x_{\mathrm{one}}=F_{\mathrm{one}}^i\left(e\right),x_2=F_2^i\left(e\right),i=\overline{\mathrm{one,}I},\left(\mathrm{one}\right)$$

where I is the number of road network elements; e - has the meaning of a natural parameter or path length [3-6].

You can approximately go to form (1) if the description of the road network elements is given in the form of arrays

$$\left\{X_r^i,r=\overline{0M_i}\right\},{\left(X_r^i\right)}^T=\left[\begin{array}{cc}{x}_{\mathrm{one}r}^i& x_{2r}^i\end{array}\right],\left(2\right)$$

used, in particular, in the formation of electronic maps. In this case

$$e_{ir}={\displaystyle \sum {}_{m=0}^r\sqrt{{\left(\Delta X_m^i\right)}^T\left(\Delta X_m^i\right)}},e_{i0}=0\left(3\right)$$

Where

$$\Delta X_r^i=X_r^i-X_{r-\mathrm{one}}^i,r=\overline{\mathrm{one,}{M}_i}.\left(\mathrm{four}\right)$$

From (2), (3) follows a discrete analogue (1)

$$\left\{X_r^i,e_{ir},r=\overline{0M_i},i=\overline{\mathrm{one,}I}\right\},\left(5\right)$$

on the basis of which an approximate representation is possible (1).

For each element of the road network, the dependence of the bearing values on the natural parameter is calculated

$${\alpha }^i\left(e\right)=arctg\left[\frac{F_2^i\left(e\right)-x_{2un}}{F_{\mathrm{one}}^i\left(e\right)-x_{\mathrm{one}un}}\right],i=\overline{\mathrm{one,}I},\left(6\right)$$

where x _1un , x _2un - coordinates of the measuring point.

Relations (6) constitute converted a priori data on the structure of the road network in relation to the measuring point. Note that the characteristics (6) are unique and each of them describes the corresponding element of the road network.

The carried out measurements:

- α _ISM (t), α _ISM (t + Δt) - bearings of the object at time t and (t + Δt), respectively, determined from one spatial point at which the measuring point is located;

- ν _ISM - the velocity of the object along the road, the value of which on [t, t + Δt], is assumed to be unchanged.

Note that the bearings α _ISM (t), α _ISM (t + Δt) are determined at the measuring point by the signal emitted by the object and the identification code containing it, the speed is determined by the object, and the signal proportional to it is encoded and the received code is transmitted via the radio data channel to the measuring point, where after receiving and decoding determine the value of the measured speed.

According to the measured bearing α _ism (t) from the solution of the equations

$${\alpha }^i\left(e\right)={\alpha }_{\mathrm{and}sm}\left(t\right),i=\overline{\mathrm{one,}I}\left(7\right)$$

many roots are defined for road network elements

$$e_i^{*}\left(t\right)=e_i^{*},i=\overline{\mathrm{one,}I},\left(8\right)$$

corresponding to many estimates of the possible location of the object

$$x_{\mathrm{one}i}^{*}=F_{\mathrm{one}}^i\left(e_i^{*}\right),x_{2i}^{*}=F_2^i\left(e_i^{*}\right),i=\overline{\mathrm{one,}I}\left(9\right)$$

Coordinates (9) determine the intersection point of the line of position of the direction finder corresponding to the bearing α _ism (t), and elements of the road network (Figure 1).

Such a plurality of location estimates, in particular, occurs if, in a two-point direction finding system that implements the known location method, one of the direction finders fails.

We show that the measurement of the velocity parameter ν _ism (t) = ν _ism makes it possible to make the location estimate unique. After encoding a signal proportional to ν _ISM , transmitting the received code via the radio channel for transmitting data from the object to the measuring point, receiving and decoding determine:

- the value of the increment of the natural parameter or the path traveled by the object in time Δt

$$\Delta e={\nu }_{\mathrm{and}sm}\Delta t;\left(10\right)$$

- the set of possible bearing values corresponding to the time instant (t + Δt)

$${\alpha }_{\Delta }^i={\alpha }^i\left(e_i^{*}+\Delta e\right)\left(\mathrm{eleven}\right)$$

Note that for various elements of the road network, dependencies (6) are different. Thus, the values of (11) will differ from each other.

The decision on the location of the object is carried out as a result of comparing the bearing values possible for each element of the road network, determined from (11), and the measured value of the bearing α _ISM (t + Δt) identified by the identification code with the object,

$$i^{*}=\arg {\min }_{i=\overline{\mathrm{one,}I}}\left\{{\left({\alpha }_{\mathrm{and}sm}\left(t+\Delta t\right)-{\alpha }_{\Delta }^i\right)}^2\right\}.\left(12\right)$$

Thus, an assessment of the location of an object is defined as

$$x_{\mathrm{one}}^{*}=F_{\mathrm{one}}^{i*}\left(e_{i*}^{*}\right),x_2^{*}=F_2^{i*}\left(e_{i*}^{*}\right).\left(13\right)$$

It should be noted that an autonomous measurement (measurements ν _ISM ) with subsequent coding of a signal proportional to ν _ISM , transmitting the received code over the radio data transmission channel to the measuring station is fragmented and is carried out only at the beginning of the process of tracking the object and after the object passes any intersection point of road network elements. As soon as the distinction problem is solved (the element of the road network on which the object is located is determined), further tracking can only be carried out based on the results of bearing measurements.

A comparative analysis of the proposed method and the known method of location location of an object on a plane.

1. The measurement of bearings in the inventive method is carried out from one spatial point at which the measuring point is located, whereas in the known method there are two direction finders and they are spaced apart in space.

2. The measurement of bearings in the present method is carried out by one direction finder for two points in time according to signals containing the identification code of the object, while in the known method of measurement is carried out simultaneously by two direction finders.

3. In the claimed method additionally carry out an autonomous measurement of the speed of the object along the road.

4. In the inventive method, a signal proportional to the measured speed is encoded and the received code is transmitted over the radio data channel to the measuring point, where, after reception and decoding, the measured speed value is determined.

5. The claimed method involves a priori information about the structure of the road network, presented, for example, in the form of electronic maps.

Consider an example.

, $$F_2^1\left(e\right)=\frac{e\sqrt{2}}{2}$$

, $$F_1^2\left(e\right)=\frac{e\sqrt{5}}{5}$$

, $$F_2^2\left(e\right)=\frac{e2\sqrt{5}}{5}$$

(фиг.2).Let I = 2 and $$F_{\mathrm{one}}^{\mathrm{one}}\left(e\right)=\frac{e\sqrt{2}}{2}$$

, $$F_2^{\mathrm{one}}\left(e\right)=\frac{e\sqrt{2}}{2}$$

, $$F_{\mathrm{one}}^2\left(e\right)=\frac{e\sqrt{5}}{5}$$

, $$F_2^2\left(e\right)=\frac{e2\sqrt{5}}{5}$$

(figure 2).

In Figure 2, through D1 and D2, the first and second elements of the road network are indicated, respectively.

Obviously, the above description satisfies the condition [3]

, $$i=\overline{\mathrm{1,2}}$$

, то есть е является натуральным параметром. $$\left\{{\left(\frac{d{F}^i}{de}\right)}^T\left(\frac{d{F}^i}{de}\right)\right\}=\mathrm{one}$$

, $$i=\overline{\mathrm{1,2}}$$

, that is, e is a natural parameter.

We define the coordinates of the measuring point as X _1un = g = 7000, x _2un = 0 (hereinafter, the parameters are given in dimensionless units).

Then, in accordance with (6)

$${\alpha }^{\mathrm{one}}\left(e\right)=arctg\left[\frac{e}{e-g\sqrt{2}}\right],{\alpha }^2\left(e\right)=arctg\left[\frac{2e}{e-g\sqrt{5}}\right].\left(\mathrm{fourteen}\right)$$

, ν_изм=10. Откуда в соответствии с (8)Suppose that as a result of the measurements, the following data were obtained: $${\alpha }_{\mathrm{and}sm}\left(t\right)=\frac{3}{\mathrm{four}}\pi$$

, ν _meas = 10. Where in accordance with (8)

, $$e_2^{*}=\frac{\sqrt{5}}{3}g$$

. $$e_{\mathrm{one}}^{*}=\frac{\sqrt{2}}{2}g$$

, $$e_2^{*}=\frac{\sqrt{5}}{3}g$$

.

Then it follows from (10) that

$$\Delta e=10\Delta t\left(\mathrm{fifteen}\right)$$

and

$$a_{\Delta }^i=a^i\left(e_i^{*}+10\Delta t\right).\left(16\right)$$

, $${\overline{x}}_2\left(t\right)=\frac{2}{3}g$$

.The dependency graphs (14) are presented in FIG. 3. Decision making is carried out in accordance with (12). For example, if Δt = 10 and the measurement yields the result α _ism (t + Δt) = 2.4 (Figure 3.), then i * = 2, and the location coordinates for t are determined from (13) in accordance with the relations $${\overline{x}}_{\mathrm{one}}\left(t\right)=\frac{g}{3}$$

, $${\overline{x}}_2\left(t\right)=\frac{2}{3}g$$

.

The structural diagram of a device that implements a method of single-position radar of moving objects on a road network is presented in FIG. 4.

In Fig. 4, the following notation is used: 1 - a moving object, including 1 ₁ - a unit for measuring speed (speedometer) and 1 ₂ - a unit for encoding and transmitting radio signals; 2 - block receiving radio signals and decoding - direction finder; 3 - amplifier with gain k _y = Δt; 4 - block determining the values of the natural parameter corresponding to the points of intersection of the position line of the direction finder and road network elements; 5 - block summation; 6 - block determining the possible values of the bearing; 7 - block comparison; 8 - block selection of the value of the natural parameter; 9 - block estimates the location coordinates.

On the object 1 in the speed measuring unit 1 ₁ measure the speed of movement of the object along the road network element. The measurement result from the output of block 1 _{1 is} transmitted to the input of the coding and transmission of radio signals 1 ₂ . Further, from the output of block 1 _{2, a} radio signal containing a code for the speed of movement of an object along an element of the road network is transmitted via a radio data channel to the input of block 2 for receiving radio signals and decoding — direction finder. Block 1 ₂ provides the emission of a radio signal continuously, supporting the functioning of the radio channel. In block 2, based on the processing, taking into account the identification code of the object, a signal is proportional to the speed measured at the object, and the values of bearings α _ISM (t + Δt) and α _ISM (t) of the object are determined. A signal proportional to α _MOD (t), with the output 2 ₂ is fed to the input unit 4 determine the natural parameter values corresponding to points of intersection of the line position finder and elements of the road network. The functioning of the side 4 is carried out in accordance with (6) - (8). The output 2 _{3 of} block 2 is connected to the input of amplifier 3, the output of which, in turn, in accordance with (10), a signal is generated proportional to the estimate of the distance traveled over Δt. A signal proportional to the estimate of the distance traveled by Δt from the output of block 3 is fed to input 5 ₀ of summation block 5. In block 5, the estimate of the distance traveled is summed with the values of the natural parameter, which from the outputs 4 ₁ ... 4 _{I of} block 4 are fed to the inputs 5 ₁ ... 5 _{I of} block 5. The predicted values of the natural parameters for each element of the road network from outputs 5 _{I + 1} ... 5 _2I arrive respectively at the inputs 6 ₁ ... 6 _I block 6 determine the possible values of the bearing. The bearing values for t + Δt, possible for each element of the road network, are calculated in accordance with (6), (11) and from the outputs 6 _{I + 1} ... 6 _{2I of} block 6 go to the inputs of comparison block 7. In block 7, the bearing values, possible for each element of the road network, are compared with the measured bearing value α _ism (t + Δt) of the object corresponding to the established identification code received at input 7 _{0 of} block 7 from output 2 _{1 of} block 2. Comparison is carried out in accordance with the rule (12). Its result is a signal proportional to the index of the road network element on which the object is located. This signal is supplied to the inputs 8 ₀ , 9 _0, respectively, of a block 8 for selecting the value of a natural parameter and a block 9 for estimating the location coordinates. In block 8, from the values of the natural parameter arriving at the inputs 8 ₁ ... 8 _I from the outputs 4 ₁ ... 4 _{I of} block 4, a choice is made of its value that corresponds to the index defined in block 7. A signal proportional to the selected value of the natural parameter from the output of block 8 is fed to input 9 _{1 of} block 9. In block 9, in accordance with (13), the coordinates of the location of the object are determined.

Information sources

1. Radio engineering systems / ed. Yu.M. Kazarinova. M .: Academy.

2. Kondratiev B.C., Kotov A.F., Markov L.N. Multiposition radio engineering systems. M .: Radio and communication. 1986.

3. Dubrovin B.A., Novikov S.P., Fomenko A.T. Modern Geometry: Methods and Applications. M .: Nauka, 1986.660 s.

4. Khutortsev V.V. The principles of spatial differential filtering of the parameters of the trajectories of objects moving along one-dimensional manifolds // Radio engineering and electronics. 1993.V. 38. No. 6. S.1026-1036.

5. Khutortsev VV Spatial differential filtering of Markov processes on one-dimensional stochastic manifolds // Automation and Telemechanics. 1994.V.8. No. 6. S.117-125.

6. Khutortsev V.V. The principles of spatial differential adaptive filtration of Markov processes on one-dimensional manifolds // Radio engineering and electronics. 1994.V. 39. No. 8. S.1637-1646.

Claims (1)

A single-position radar method for moving objects on a road network, which consists in measuring the angle of arrival of an electromagnetic wave (bearing) α _ISM (t) from an object from one measuring point, the position of which is known, characterized in that the signals emitted by the object contain its identification code, simultaneously a radiation signal measured object velocity ν _edited its displacement along the element of the road network, a signal proportional to the measured speed, and encode the resulting code is transmitted via the data radio channel at the measuring point, upon receiving and decoding the obtained value of the measured speed, the duration of a time interval Δt is measured repeatedly _edited bearing α (t + Δt), identifying it by the object identification code, determine the length of the path traversed Δe = Δtν _edited for time ∆t, according to the measured bearing α _ism (t) and the parametric models of the bearing α ⁱ (e), $$i=\overline{\mathrm{one,}I}$$

defined in the natural parameter function for each element of the road network, determine the values of the natural parameter $$e_i^{*}$$

, $$i=\overline{\mathrm{one,}I}$$

corresponding to the intersection points of the position line for the measured bearing α _ism (t) and elements of the road network, for each of these elements possible values of bearings are determined $${\alpha }^i\left(e_i^{*}+\Delta e\right)$$

, $$i=\overline{\mathrm{one,}I}$$

corresponding to the displacement of the object by a distance Δe, and from the condition of minimum mismatch between them and the re-measured bearing α _ism (t + Δt) determine the number i * of the road network element on which the object is located, determine the coordinates of the location of the object as the coordinates of the point of intersection of the position line corresponding to the measured bearing (α _ISM (t) or α _ISM (t + ∆t)) and the i * th element of the road network.

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