RU2695642C1 - Method for determining the location of a ground-based radiation source - Google Patents

Abstract

FIELD: radio equipment.

SUBSTANCE: invention relates to radio engineering and can be used to locate a ground-based radiation source based on results of its two-dimensional direction finding from an aircraft board. Result is achieved by the fact that the method of determining the location of a ground-based radio-frequency source involves two-dimensional direction finding of a source using a direction finder located on an aircraft, synchronously with this measurement of own spatial coordinates of aircraft and determination from them and results of direction finding for all time of flight coordinates of source in horizontal coordinate plane based on ensuring minimum error, at that before beginning direction finding, determining the height of the area in places of the possible position of the source, coordinates of the source are determined additionally with due allowance for this height, additionally the height of the radiation spot is determined as the height of the area at the point of the obtained coordinates of the source. Source coordinates are determined by method of least squares of weighted distances from source at given height to lines of two-dimensional bearings, as well as by maximum likelihood method as a position of minimum sum of squares of differences between measured and calculated to places of possible source position of components of vectors of two-dimensional bearings.

EFFECT: technical result is determination of elevation of radiation point and high accuracy of determining coordinates of radiation source in hilly area in 1,6-2,2 times.

3 cl, 6 dwg

Description

The invention relates to the field of radio engineering and can be used to determine the location of a ground-based radiation source based on the results of its two-dimensional direction finding from an aircraft.

There is a method of multiple direction finding of a ground target, in accordance with which a target is detected on an aircraft by its radio emission with measurement of the angle of arrival of radio waves in the horizontal plane, the coordinates of the flight points are measured simultaneously, from the totality of all during the flight measurements by processing them, based on ensuring a minimum error , determine the coordinates of the source on the plane.

Processing of the measurement results is carried out by the method of least squares of angles to the lines of bearings, while the coordinates of the reference point are determined as the intersection points of any pair of bearings, the angle between which lies in the range from 30 to 120 degrees, then the bearing to the reference point and the distance from it to each direction finding point, after which the coordinates are refined according to the results obtained through algebraic transformations [Melnikov Yu.P. Aerial radio intelligence (methods for evaluating effectiveness). - M .: Radio engineering, 2005, p.148-158].

There is a known variant of processing the measurement results by the maximum likelihood method, while the coordinates are determined by the minimum sum of the squares of the differences between the measured and calculated to the places of the possible position of the source bearings with determining the minimum position by numerical methods [Rabtsun A.V. Estimation of the maximum likelihood of coordinates of signal sources in multi-position direction finding. "Radio Engineering", 1987, No. 9, p. 9-10].

Bearing line means a straight line passing through the direction finding point and the source of radio emission.

This method does not provide determination of the coordinates of the radiation source according to the results of a single direction finding, on the line of the direction finding base and near it in a straight flight, the height of the radiation site, the disadvantage is also the low accuracy of positioning due to the use of angular measurements in only one horizontal plane.

A known method for determining the coordinates of a ground-based source of radio emission during direction finding from an aircraft, including periodic direction finding of a source in the azimuth plane of the direction finder, forming an auxiliary plane orthogonal to it in the direction of the bearing in the normal earth coordinate system taking into account the spatial position of the aircraft, then determining the source position lines, as the intersection lines of independent pairs of auxiliary planes, pairwise positioned Contents source as lines of intersection points with the position of the surface of the earth and locating the source by weighting pairwise ranking results. The intersection points are determined using an iterative procedure for their search, and the convergence step is selected depending on the roughness of the Earth’s surface in the direction finding zone [RU, No. 2610150, G01S 1/08, G01S 5/02, publ. 02/08/2017].

The disadvantages of the method are the need to measure bearings at least twice, the significant cost of performing iterative procedures, the low accuracy of determining coordinates due to the use of angular measurements in only one horizontal plane and not strict, outside the specified accuracy criteria, empirical solutions that do not guarantee a positive effect outside narrow borders. The coordinates are not determined on the line of the direction finding base and near it during a straight flight.

Of the known closest to the proposed technical essence is a method for determining the location of a ground target, including two-dimensional direction finding of a source using a direction finder located on an aircraft, simultaneously measuring the spatial coordinates of the aircraft and determining the coordinates of the source by processing all of the results during the flight direction finding measurements based on ensuring the minimum error [V. Ufaev Determining the location of ground targets based on the results of two-dimensional direction finding from flight-lifting means // Antennas. 2015. Issue. 5 (216). S.58-61].

The coordinates of the source are determined by the method of least squares of the weighted distances to the lines of two-dimensional bearings using the formulas for the abscissa and ordinate, respectively

,

,

,

,

,

,

,Where

,

,

,

,

,

,

,

,

,

,

,

,

,

– собственные пространственные координаты

пункта пеленгования по ординате, абсциссе и аппликате,

,

– составляющие вектора двухмерного пеленга по этим координатным осям.

- own spatial coordinates

direction finding by ordinate, abscissa and applicate,

,

- components of the two-dimensional bearing vector along these coordinate axes.

,There is a known variant of determining coordinates by the maximum likelihood method as the position of the minimum sum of the squares of the differences between the measured and calculated to the places of the possible position of the source components of the vectors of two-dimensional bearings, while the position of the minimum is determined by numerical methods, and the calculated components are found by the formulas

,

– наклонная дальность до источника на горизонтальной земной поверхности,

– абсцисса и ордината мест возможного положения источника.Where

- the inclined range to the source on a horizontal earth's surface,

- abscissa and the ordinate of the places of the possible position of the source.

The disadvantages of this method are the low accuracy of determining coordinates in hilly terrain, due to the initial assumption that the source is on a flat earth surface without taking into account the relief, the lack of determining the height of the radiation site.

The technical result of the present invention is to determine the height of the radiation site and improve the accuracy of determining the coordinates of the source on the horizontal coordinate plane.

The specified technical result is achieved by the fact that in the known method for determining the location of a ground source of radio emission, including two-dimensional direction finding of a source using a direction finder located on an aircraft, simultaneously measuring the spatial coordinates of the aircraft and determining from them and direction finding results for the entire duration of the flight coordinates of the source in the horizontal coordinate plane based on ensuring the minimum error, according to the invention, up to direction finding beginnings determine the height of the terrain in places of the possible position of the source, the coordinates of the source are determined additionally taking into account this height, the height of the radiation site is additionally determined as the height of the terrain at the point of the received coordinates of the source.

The specified technical result is also achieved by the fact that the coordinates of the source are determined by the method of least squares of the weighted distances from the source at a given height to the lines of two-dimensional bearings, while the source coordinates are initially estimated at the height of the radiation site equal to the average height of the terrain in the working area, and then the height is specified according to the coordinates obtained, the coordinates at the specified height and height according to the adjusted coordinates, and the abscissa and the ordinate of the source are determined by the formulas corresponding nno

,

,

,

,

,

,Where

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

– собственные пространственные координаты

пункта пеленгования по ординате, абсциссе и аппликате,

,

– составляющие вектора двухмерного пеленга по этим координатным осям,

– задаваемая высота места излучения.

- own spatial coordinates

direction finding by ordinate, abscissa and applicate,

,

- components of the vector of a two-dimensional bearing along these coordinate axes,

- set height of the radiation site.

The specified technical result is also achieved by the fact that the coordinates of the source are determined by the maximum likelihood method as the minimum position of the sum of the squares of the differences between the measured and calculated components of the vectors of two-dimensional bearings to the places of the possible position of the source, while the minimum position is determined by numerical methods, and the calculated components are determined by the formulas

,

,

– наклонная дальность до источника,

– абсцисса и ордината мест его возможного положения,

– функция рельефа местности, как зависимость высоты от координат источника.Where

- inclined range to the source,

- the abscissa and the ordinate of the places of its possible position,

- the function of the terrain, as the dependence of the height on the coordinates of the source.

The solution to the technical problem is based on taking into account the topography of the terrain, the height of the places of the possible position of the source as a function of its coordinates on the horizontal coordinate plane, and the introduction of corrections taking into account this information in the operation of the prototype method. The necessary data on the terrain is contained in digital maps, for example, the GIS "Panorama" GIS system provides the construction and use of three-dimensional models of the earth’s surface [GEOINFORMATION SYSTEM "PANORAMA X64" (GIS Panorama). Building a 3D model. PARB.00227-019807. http://gistoolkit.ru/download/doc/model3d.pdf].

The essence of the corrections consists in the introduction of the third coordinate, the height of the radiation site, and the determination of two-dimensional bearings and distances to the bearing line taking this factor into account.

с последующим умножением на задаваемую высоту и добавлением к суммам предусмотренным ранее.A modification of the calculation formulas of the prototype method when determining the coordinates by the least squares method consists in the accumulation of additional quantities

followed by multiplication by a specified height and adding to the amounts provided earlier.

The uncertainty of the height is overcome by its sequential refinement at the initial set value equal to the average height of the terrain, when the minimum average errors of the initial determination of coordinates are achieved.

The paradox of this solution is that with the help of operations (formulas) designed for a known target height, the desired effect is achieved with height uncertainty.

This is explained by the fact that taking into account information about the height relative to the principle adopted in the prototype: the height is the same and equal to zero, allows you to more accurately calculate both two-dimensional bearings and the distance from the measured bearings from the lines, and as a result, to achieve a technical result: to determine the height of the place radiation source and improve the accuracy of determining its coordinates.

These advantages, as well as features of the present invention are illustrated by the accompanying figures.

Figure 1 presents a structural diagram of an information-measuring system for implementing the inventive method;

figure 2 - terrain along the ordinate axis;

figure 3 is a cross-section of the terrain in the working area;

figure 4 - dependence of the mean square errors of determining the coordinates on the range of the system from one direction finding point, on the left - in the horizontal plane, on the right in height;

figure 5 - dependence of the mean square errors of determining the coordinates on the range of the system of two bearing points, left - in the horizontal plane, right height;

figure 6 - dependence of the mean square errors of determining the coordinates of the range of the system of three bearing points, left - in the horizontal plane, right height.

The information-measuring system of FIG. 1 contains 1 — a direction finder, 2 — an on-board navigation system, 3 — a coordinate calculator, 4 — a height estimation unit, 5 — a medium-height memory (memory), 6 — a switch. The output of the direction finder 1 and the on-board navigation system 2 is connected respectively to the first and second input of the coordinate calculator 3, the third input of which is connected to the output of the switch 6, the first input of which is connected to the output of the height estimation unit 4, and the second to the output of the medium-height storage device 5 The output of the coordinate calculator 3 is connected to the input of the height estimation unit 4 and is the first output of the information-measuring system, the second output of which is the output of the height estimation unit 4.

The direction finder 1 provides periodic two-dimensional direction finding with the presentation of the results in the form of components of the bearing vector along the coordinate axes. Bearing vector is understood to be a single vector directed from the position of the aircraft to the source. The measurement of the components of the bearing vector is provided, for example, by a phase method using a three-dimensional antenna array [V. Ufaev Determining the location of ground targets based on the results of two-dimensional direction finding from flight-lifting means // Antennas. 2015. Issue. 5 (216). P.58-61] or by methods of amplitude two-dimensional direction finding [Kozmin V.A., Ufaev V.A., Ufaev A.V. Methods of amplitude two-dimensional direction finding // Antennas. 2017. Issue. 6 (238). S.38-44].

In the on-board navigation system 2, synchronously with direction-finding, the aircraft’s own spatial coordinates are measured in the horizontal plane and in height. The center of the coordinate system is combined with the center of the working area at zero height. Measurements are performed by known methods and devices [Control systems and on-board digital computer systems of aircraft. Ed. N.M. Lysenko. M .: VVIA them. prof. NOT. Zhukovsky, 1990, p. 244-259].

Coordinate calculator 3 is used to determine the coordinates of the source in the horizontal plane based on the results of all during the flight measurements of bearings input 1, own spatial coordinates of the aircraft, input 2 and information about the elevation of the possible position of the source, input 3.

The unit for estimating the height 4 provides a determination of the height of the places of the possible position of the source based on its coordinates on the horizontal coordinate plane. It can be performed on the basis of a storage device into which information about the terrain is preliminarily entered with a given step of quantization of coordinates or directly as a functional converter with the implementation of the terrain function based on the results of preliminary conversion of digital cartographic information.

In the storage device 5 enter the value of the average height of the terrain in the working area of the information-measuring system.

The switch 6 provides the supply to its output information either from the unit for estimating the height 4 or from the storage device 5.

The operation of the information-measuring system and the process of determining the location of a ground source of radio emission occurs as follows.

высоты от координат излучателя: абсциссы

и ординаты

. Соответствующим образом конфигурируют блок оценки высоты 4, а в ЗУ 5 запоминают среднее значение высоты в рабочей зоне.Prior to the start of the flight, determine the height of the terrain in places of a possible position of the source as a function of the terrain in the form of a dependence

heights from emitter coordinates: abscissas

and ordinates

. The height estimation unit 4 is configured accordingly, and the average value of the height in the working area is stored in the memory 5.

, абсциссу

и аппликату

, где

– номер позиции пеленгования.During the flight using the on-board navigation system 2 periodically measure the spatial coordinates of the aircraft:

abscissa

and applicate

where

- number of direction finding position.

Synchronously with this using the direction finding 1 perform two-dimensional direction finding with the presentation of the results in the form of components of the bearing vector along the coordinate axes.

The true values of the components in ordinate, abscissa and applicate are determined by the relative position of the aircraft and the radiation source

(1)

(one)

, сопровождаются погрешностями с постоянной и одинаковой дисперсией составляющих двухмерного пеленга.Measurements, mark them with a bracket above

are accompanied by errors with constant and uniform dispersion of the components of the two-dimensional bearing.

The source coordinates are determined by measuring two-dimensional bearings and the aircraft’s own coordinates, taking into account the terrain (height) of the terrain, based on ensuring a minimum error. This operation is carried out in the coordinate calculator 3.

In accordance with the general definition of the distance from a point to a straight line in space [Bronstein I.N., Semendyaev K.A. Math reference. –M .: Nauka, 1986, p. 205], the distances to the line of the measured two-dimensional bearing in the coordinate planes are equal

,

,

,

,

, (2)

, (2)

– задаваемая высота места излучения.Where

- set height of the radiation site.

Given the definition (2), by the method of least squares of the weighted distances from the source at a given height to the lines of two-dimensional bearings, the unknown abscissa and the ordinate of the source position are determined by the formulas

. (3)

. (3)

The initial values in operation (3) are obtained by functional transformation of measurements and summing the results according to the formulas

(4)

(four)

,

,

– весовые коэффициенты.Where

,

,

- weighting factors.

Weighting factors are inversely proportional to the estimated variance of the distances (2) to the bearing line.

…

целесообразно проводить рекуррентно, путём накопления преобразованных результатов измерений по соответствующим для них формулам. В этом случае не требуется регистрации всех предыдущих результатов измерений, достаточно преобразовать вновь полученные результаты и добавить к уже имеющимся семи соответствующим величинам.Determination of the initial values in formulas (3)

...

it is advisable to carry out recursively, by accumulating the converted measurement results according to the corresponding formulas. In this case, it is not necessary to register all previous measurement results, it is enough to convert the newly obtained results and add to the existing seven corresponding values.

Since initially the height of the radiation site is unknown, the processing is performed in stages.

, при этом минимизируются погрешности первичной оценки. В этом случае через переключатель 6 на вычислитель координат 3 из ЗУ 5 поступает значение средней высоты рельефа местности. Преобразованием по формуле (3) получают первичную оценку горизонтальных координат

и по ним в блоке оценки 4 уточняют высоту места излученияInitially, the source coordinates on the horizontal coordinate plane are estimated using formulas (3) when setting the height of the radiation site equal to the average height of the relief of the working area

, while minimizing errors in the initial assessment. In this case, through the switch 6 to the coordinate calculator 3 from the memory 5 the value of the average height of the terrain is received. A transformation according to formula (3) gives an initial estimate of the horizontal coordinates

and according to them in the evaluation unit 4 specify the height of the radiation

. (5)

. (five)

Then, the adjusted height value is used as the specified height of the radiation site and the horizontal coordinates of the emitter, which are output to output 1 of the information-measuring system, are refined using formulas (3). Then, according to them, in the evaluation unit 4, by the formula (5), the height of the radiation site is specified with the output of the output of the 2 system.

The coordinates of the source using the maximum likelihood method determine how the minimum position of the sum of the squares of the differences between the measured and calculated to the places of the possible position of the source components of the vectors of two-dimensional bearings by the formula

. (6)

. (6)

, после чего по формулам (1) определяют расчётные двухмерные пеленги с переходом к завершающему преобразованию (6). Минимизацию двухмерного функционала в (6) выполняют численными методами, например на основе квантования рабочей зоны с заданным исходя из требуемой инструментальной точности шагом. После получения координат (6) по формуле (5) определяют высоту места излучения.In this case, the values of the terrain function are received from the height estimation unit 4 through the switch 6

then, using formulas (1), the calculated two-dimensional bearings are determined with the transition to the final transformation (6). Minimization of the two-dimensional functional in (6) is performed by numerical methods, for example, based on quantization of the working area with a given step based on the required instrumental accuracy. After obtaining the coordinates (6) by the formula (5) determine the height of the radiation site.

The use of this processing option is advisable with relatively weak restrictions on hardware and computing resources and the need to ensure a minimum of a minimum of coordinate determination errors.

The effectiveness of the invention is expressed in ensuring the determination of the height of the radiation site and increasing the accuracy of determining the coordinates of the source.

A quantitative assessment of accuracy was performed by modeling in relation to the hilly terrain of Fig. 2 with a hill height of up to 500 m in the working area of 20 · 20 km at an aircraft flight altitude of 2000 m. The terrain function was set analytically

. (7)

. (7)

в центре системы, в двух пунктах

, размещённых на удалении по горизонтали ±5 км от центра рабочей зоны, в трёх пунктах

с эквидистантным расположением на соосной с центром окружности радиусом 5 км и опорным пунктом на оси ординат на удалении +5 км.Accepted flight altitude of the aircraft 2000 m with direction finding in one point

at the center of the system, at two points

located at a horizontal distance of ± 5 km from the center of the working area, at three points

with an equidistant arrangement on a circle with a radius of 5 km coaxial with the center of the circle and a reference point on the ordinate axis at a distance of +5 km.

и по высоте

источника располагаемого на оси ординат, сечение рельефа местности по которой показано на фиг.3.The mean square errors of determining the coordinates in the horizontal coordinate plane were estimated

and in height

the source located on the ordinate axis, the cross-section of the terrain on which is shown in Fig.3.

Two-dimensional direction finding was simulated using a volumetric antenna array of the minimum composition of 4 antennas [Ufaev V.A. Determining the location of ground targets based on the results of two-dimensional direction finding from flight-lifting means // Antennas. 2015. Issue. 5 (216). S.58-61] with an average square error of direction finding 1 deg. Measurements of the aircraft’s own spatial coordinates were believed to be accurate.

, слева – для координат на горизонтальной плоскости, справа – по высоте. Тонкой линией с кружками на фиг.4-6 слева показаны результаты для способа-прототипа, а жирной – для предлагаемого решения с применением метода наименьших квадратов.The results in the form of dependences of the errors in determining coordinates on the distance of the source position to the center of the working area are shown in Figs. 4, 5, 6, respectively

, on the left - for coordinates on the horizontal plane, on the right - for height. The thin line with circles in Figs. 4-6 on the left shows the results for the prototype method, and the thick line for the proposed solution using the least squares method.

Figure 4-6 on the right, the dashed line shows the results when estimating the coordinates using the maximum likelihood method, and the solid bold line shows the least squares method.

Analysis of the results shows that the proposed method relative to the prototype method provides a determination of the height of the radiation site and increase the accuracy of determining the horizontal coordinates of the radiation source using the least squares method on average 1.6-2.2 times. The use of the maximum likelihood method in the specified conditions allows you to further increase the accuracy by 6% -10%.

The claimed method for determining the location of a ground source of radio emission is applicable in systems of radio monitoring, electronic intelligence, navigation and landing of aircraft on drive transmitters.

Claims (12)

1. A method for determining the location of a ground-based source of radio emission, including two-dimensional direction finding of a source using a direction finder located on an aircraft, synchronously with this, measuring the spatial coordinates of the aircraft and determining from them and results of direction finding for the entire time the coordinates of the source are in flight in the horizontal coordinate plane based on ensuring a minimum error, characterized in that prior to the direction finding determine the height of the terrain in places possible second source position, source coordinates determined further in view of this height, further comprising determining the height of the radiation space as the height of the terrain at point received source coordinates. 2. The method according to claim 1, characterized in that the coordinates of the source are determined by the method of least squares of the weighted distances from the source at a given height to the lines of two-dimensional bearings, while initially coordinates of the source are estimated at a height of the radiation site equal to the average height of the terrain in the working area, then specify the height according to the coordinates obtained, the coordinates at the specified height and the height according to the specified coordinates, and the abscissa and the ordinate of the source are determined by the formulas, respectively

, Where

,

,

,

,

,

,

,

,

,

,

- own spatial coordinates

direction finding by ordinate, abscissa and applicate,

,

- components of the vector of a two-dimensional bearing along these coordinate axes,

- set height of the radiation site. 3. The method according to claim 1, characterized in that the coordinates of the source are determined by the maximum likelihood method as the minimum position of the sum of the squares of the differences between the measured and calculated to the places of the possible position of the source components of the vectors of two-dimensional bearings, while the minimum position is determined by numerical methods, and the calculated components are determined according to the formulas

, Where

- inclined range to the source,

- the abscissa and the ordinate of the places of its possible position,

- the function of the terrain as a dependence of the height on the coordinates of the source.

Images