RU2545526C1 - Method for radar location of objects on road network - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method includes measuring signals proportional to the arrival angles of an electromagnetic wave from a radio signal source at two spaced-apart measurement stations, the position of which is known. The obtained signals which are proportional to the arrival angles of the electromagnetic wave are converted to signals which are proportional to the posterior probability of finding an object at elements of the road network. The most probable element of the road network is determined based on selecting the maximum signal from the obtained set. For said element of the road network, signals which are proportional to the arrival angles of the electromagnetic wave are converted to signals which are proportional to the length thereof from a given reference point to the point of finding the radio signal source and the uniquely defining value of the coordinates of the object.

EFFECT: high accuracy of determining coordinates of an object - radio signal source.

6 dwg

Description

An object of the invention is a method for radar-tracking objects - radio signal sources located on a 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 low accuracy, due to the possibility of false estimates of location coordinates, suggesting that the object is outside the road network.

There is also known a method of radar location of objects - sources of a radio signal on a plane [2], which consists in measuring the angles of arrival of an electromagnetic wave from an object - a source of a radio signal in 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 received corners. Its disadvantage is also low accuracy, due to the possibility of false estimates of location coordinates, suggesting that the object is outside the road network.

The purpose of the invention: improving the accuracy of determining the coordinates of the location of the object - the source of the radio signal located on the road network, due to the rational use of a priori data on its structure and eliminating the possibility of false estimates of location outside such a network.

Justification of the invention. A priori data on the road network are as follows. Each of its elements is described by a parametric dependence (Figure 1)

where I is the number of road network elements; l≥0 - 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

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

Where

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

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

,

,

, от которой отсчитывают его длину.It should be noted that, by virtue of (3), a reference point is determined for each element of the road network

,

,

, from which its length is counted.

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

where x _11ip , x _21ip and x _12ip , x _22ip are the coordinates of the first and second measuring points, respectively.

Relations (6) constitute converted a priori data on the structure of the road network in relation to measuring points.

,

. Тогда с учетом (6) отношения правдоподобия, соответствующие проведенным наблюдениям, могут быть представлены в виде [2]Let the bearings of the object α _1meas , α _2meas obtained in the measuring points, are characterized by the dispersion of the measurement, respectively

,

. Then, taking into account (6), the likelihood ratios corresponding to the observations made can be represented in the form [2]

The posterior probability of an event associated with the object belonging to the i-th element of the road network is evaluated in accordance with (7) as the result of indirect measurements

where p _i is the a priori probability of the event associated with the object belonging to the i-th element of the road network.

The choice of the number of the road network element is carried out according to the criterion of the maximum of posterior probability in accordance with the decision rule

The length of the section of the i ^* -th element of the road network from the reference point, for which l = 0 is assumed, to the point determining the possible position of the object is estimated in accordance with the ratio

in the form of the result of indirect measurements. Note that estimate (10) meets the maximum likelihood criterion.

An illustrative assessment of the accuracy of the proposed method.

Consider a straight section of the road network element (Figure 2). Let the true position lines A ₁ B ₁ and A ₂ B ₂ intersect at an angle γ, and their position with respect to the section of the road network element is determined by the angles γ ₁ and γ ₂ (in the conditions of FIG. 2, γ ₂ <0). Obviously, γ = γ ₁ -γ ₂ .

The standard errors (RMS) of the position line for the first (σ ₁ ) and second (σ ₂ ) measuring points are associated with the RMS of measuring the primary parameters by the relations [2]

We will assume that the distance between the measuring points and the object is quite large. Then the area of the region of the uncertainty of the location of the object (approximately assumed by the parallelogram) corresponding to the known location method can be determined by the relation

where χ - choose, based on the given probability of finding the object in the region of uncertainty, for example, for the rule of three sigma χ = 6.

Consider the accuracy characteristics of the location for the proposed method. The standard deviation of the location of the object on the site of the road network element for the first and second measuring points is determined by the ratios, respectively

The expression for the mean square error, taking into account both measurements, has the form

Suppose that a section of the road network has a width equal to h. Then the area of the uncertainty area of the location of the object is determined by the ratio

and the relative gain in accuracy is

Or for the case when σ ₁ = σ ₂ = σ

Where

,

,

,

,

для ν=10 представлены на Фиг.3. Из них следует, что минимальный выигрыш в точности имеет место в случае, когда участок элемента дорожной сети совпадает с большей диагональю области неопределенности

, а максимальный - при совпадении этого участка с меньшей диагональю этой области

. При пересечении линий положения под прямым углом выигрыш в точности от γ₁ не зависит и определяется только лишь величиной параметра v (18).Dependence graphs δ (γ ₁ ) for

,

,

,

,

for ν = 10 are presented in FIG. 3. It follows from them that the minimum gain in accuracy occurs when the part of the road network element coincides with a larger diagonal of the uncertainty region

, and the maximum - when this section coincides with a smaller diagonal of this region

. When crossing the position lines at a right angle, the gain does not exactly depend on γ ₁ and is determined only by the value of parameter v (18).

The proposed method may not lead to a gain in accuracy only in cases where the χ parameter values are small and the standard deviation of the position lines is less than the width of the road network element, which is quite rare in practice.

Example.

Let the road network contains two intersecting elements (I = 2) (Figure 4). An object can equally likely be on one of them, i.e. p ₁ = p ₂ = 0.5. Measuring points (IP) are located at points with the coordinates of IP1: x _11ip = x _21ip = 0; IP2: x _12ip = 0; x _22ip = -600.

Hereinafter, numerical data are given in dimensionless units.

Consider a fragment of the plane (Figure 5) in the vicinity of the intersection of the lines of position of the protractors. We will assume that the description of the road network elements is given in the form of data arrays from which subarrays corresponding to the selected fragment can be selected.

In accordance with (3), (4), representation (19) can be reduced to the form (5)

The sequence of application of the proposed method.

1. Conversion of signals proportional to the measured angles of arrival of the electromagnetic wave in accordance with (6), (7), (8) using two-parameter nonlinear functional converters into signals proportional to the posterior probabilities of finding the object of the radio signal source on the elements of the road network.

For the conditions of the example, the result of such a conversion is the signals u ₁ = p _ps1 = 0.708, u ₂ = p _ps2 = 0.292.

2. Comparison of the signals obtained according to claim 1 with each other and determination of the largest of them.

3. Determination of the element of the road network corresponding to the largest signal. In the conditions of the example, i ^* = 1.

4. Conversion of signals proportional to the measured angles of arrival of the electromagnetic wave in accordance with (7), (10) using a two-parameter nonlinear functional converter into a signal proportional to the length of the selected road network element from a given reference point to the point of location of the radio emission source (indirect measurement of the length of the section selected road network item).

In the conditions of the example, an indirect measurement of the length of the section of the first element of the road network (i ^* = 1) from its reference point to the point of location of the object is carried out.

, j=1,2, измерена длина

участка первого элемента дорожной сети от его опорной точки до точки нахождения объекта, координаты которого, отмечены на Фиг.5.In the conditions of the example, for the values of the bearings, α _1meas = 2.824, α _2meas = 0.602 (corresponding to these bearings of the position line LP1, LP2, shown in Figs. 4, 5) under the assumption that

, j = 1.2, measured length

plot of the first element of the road network from its reference point to the point of location of the object, the coordinates of which are marked in Figure 5.

It should be noted that certain coordinates are rigidly attached to the first element of the road network, while the known method, as follows from the structure of the intersection area of the position lines (Figure 5), leads to coordinate values that do not belong to a given road network.

The structural diagram of a device that implements a method of radar objects on the road network, is presented in Figure 6.

In Figure 6, the following notation is used: block 1 — first measuring point; blocks 2 ₁ , ..., 2 _I - two-parameter nonlinear functional converters; block 3 - a decisive device; block 4 - the second measuring point; block 5 - the first switch; blocks 6 ₁ , ..., 6 _I - two-parameter nonlinear functional converters for determining the path length; block 7 - the second switch; block 8 is a one-parameter nonlinear functional converter.

, пропорциональные апостериорным вероятностям нахождения объекта на I элементах дорожной сети. Сигналы u_i,

с выходов блоков 2₁, …, 2_I поступают на входы 3₁, …, 3_I решающего устройства 3. Решающее устройство 3 в соответствии с (9) сравнивает сигналы u_i,

, выделяет максимальный

, определяет его номер i^* и формирует сигнал, пропорциональный этому номеру. Указанный сигнал поступает на управляющие входы 5₀ и 7₀ коммутаторов 5 и 7 соответственно и управляющий вход 8₀ однопараметрического функционального преобразователя 8. По этому сигналу коммутатор 5 подключает выходы, блоков 1 и 4 ко входам одного из функциональных преобразователей 6₁, …, 6_I соответствующего определенному номеру i^* элемента дорожной сети, т.е. ко входам

,

блока

. Одновременно коммутатор 7 подключает выход этого блока ко входу блока 8 функционального преобразователя. В блоке

в соответствии с (10) проводится преобразование сигналов пропорциональных углам прихода электромагнитной волны в сигнал, пропорциональный длине

i^*-го элемента дорожной сети. Сигнал, пропорциональный

, в блоке 8 преобразуется в соответствии с (1) в сигналы, пропорциональные значениям координат местоположения объекта

According to the results of processing the electromagnetic wave at the outputs of blocks 1 and 4, signals are generated proportional to the angles of arrival of the electromagnetic wave from the object - the source of the radio signal. These signals are fed to inputs 2 ₁₁ , 2 ₁₂ , ..., 2 _I1 , 2 _I2, respectively, of the functional converters 2 ₁ , ..., 2 _I. In blocks 2 ₁ , ..., 2 _{I, the} signals proportional to the angles of arrival of the electromagnetic wave are converted in accordance with (7), (8) into signals u _i ,

proportional to the posterior probabilities of finding the object on I elements of the road network. Signals u _i ,

from the outputs of blocks 2 ₁ , ..., 2 _I go to the inputs 3 ₁ , ..., 3 _{I of the} solving device 3. The solving device 3 in accordance with (9) compares the signals u _i ,

allocates maximum

, determines its number i ^* and generates a signal proportional to this number. The specified signal is fed to the control inputs 5 ₀ and 7 _{0 of the} switches 5 and 7, respectively, and the control input 8 _{0 of the} one-parameter functional converter 8. By this signal, the switch 5 connects the outputs of blocks 1 and 4 to the inputs of one of the functional converters 6 ₁ , ..., 6 _I corresponding to a certain number i ^* of the road network element, i.e. to the entrances

,

block

. At the same time, the switch 7 connects the output of this block to the input of block 8 of the functional Converter. In block

in accordance with (10), signals are transformed proportional to the angles of arrival of the electromagnetic wave into a signal proportional to the length

i ^* th element of the road network. Proportional signal

, in block 8 is converted in accordance with (1) into signals proportional to the values of the coordinates of the location of the object

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

, пропорциональные апостериорным вероятностям p_psi нахождения объекта на элементах дорожной сети, тогда как в известном способе факт привязки объекта к дорожной сети не используется.1. In the inventive method determine the signals u _i

proportional to the posterior probabilities p _{psi of} finding the object on the elements of the road network, while in the known method the fact of binding the object to the road network is not used.

2. The coordinates in the present method are determined on the basis of indirect measurement of the length of the section of the most probable element of the road network from its reference point to the point of location of the object, whereas in the known method the coordinates of the object are defined as the coordinates of the intersection point of the position lines corresponding to the measured bearings.

3. The coordinates of the location of the object, determined by using the proposed method, is rigidly attached to the corresponding element of the road network, while in the known method the point of intersection of the position lines may not be located and, as a rule, not located on the road network.

4. The claimed method rationally uses both information about the structure of the road network, generated, for example, using electronic maps, and the laws of its description, taking into account the relative position of such a network and measuring points.

Information sources

1. Radio engineering systems / ed. Yu.M. Kazarinova. M .: Academy. 2008.

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 method for radar objects on the road network, which consists in measuring the angles of arrival of an electromagnetic wave from an object - the source of the radio signal in two spatially spaced measuring points, the position of which is known, characterized in that the signals proportional to the angles of arrival of the electromagnetic wave are converted into signals proportional to posterior probabilities the location of the object on the elements of the road network, they are compared, the maximum signal is extracted from the obtained set of signals and the dividing the corresponding element of the road network, this network element traffic signals that are proportional to angles of arrival of the electromagnetic wave is converted into a signal proportional to its length from a predetermined reference point to find a point radio source and unambiguously defining the coordinates of the object location.

Images