RU2666360C1 - Target coordinates determining method and system in the “request-response” system - Google Patents

Abstract

FIELD: radar ranging.SUBSTANCE: invention relates to the field of radar ranging, and can be used in the secondary radar ranging systems during the target coordinates determining in the “request-response” system. Said result is achieved by the fact, that the target coordinates determining method in the “request-response” system using antenna, having preset aiming direction, allows to combine at least three parameters, which reflect the target position, antenna carrier position and the antenna aiming direction, at that, as the parameters using the carrier to the target distance, target altitude, carrier altitude, carrier in space angular position, antenna to the target preset angular direction relative to the carrier. At that, implementing the method system is placed on the carrier and contains antenna, directed to the target, “request-response” system configured to compare at least three parameters, representing the target position, the carrier position, and the antenna aiming direction for the target location determining, digital computing device (DCD) configured to calculate the target coordinates at the carrier and antenna on the carrier any position, as well as aimed at the target antenna altitude sensor and the angular position sensors.EFFECT: achieved technical result of the invention is increase in the target (the respondent) coordinates determining accuracy at any position of the interrogator's antenna relative to the interrogator's carrier and at the interrogator's carrier in space any position.2 cl, 3 dwg

Description

The invention relates to the field of radar and can be used in secondary radar systems when determining the coordinates of a target in a request-response system.

The prior art various methods for determining the coordinates of the target. One way is to survey the surrounding space with a needle-shaped radar beam, fix the reflected signals and determine the coordinates of the target based on the presence of the reflected signal as the current direction of the beam in space and the distance to the target, proportional to the delay in the arrival of the signal reflected from the target. The disadvantage of this method is the complexity of the antenna system, forming a radar beam in the form of a needle, and the high power of the radar transmitter, since the method relates to primary (passive) radar systems.

Another way is to determine the coordinates of the target itself using the equipment of the target and transfer the coordinates to the requesting object. The disadvantage of this method is the low noise immunity of the "interrogator - responder" si system.

Closest to the proposed technical solution is the invention "A method and system for determining the coordinates of a target in a request-response system" (US patent No. 6,933,879, published August 23, 2005, IPC: G01S 13/78, G01S 13/75, G01S 13 / 06), which is selected as a prototype. The following parameters are used to determine the coordinates of the target: the target’s height reported by the target, the height of the medium on which the system is located to determine the target’s coordinates in the request-response system, reported by the carrier’s navigation system and the difference between the direction to the target and the direction of the antenna’s aiming. Using mathematical relations, one defines a sphere with a radius equal to the measured distance to the object (sphere of equal range); a plane in the normal coordinate system (NSC) according to GOST 20058-80, parallel to the XOZ plane of the NSC, and located at the target height (target height plane); a vertical plane (perpendicular to the XOZ plane of the NSC) containing the circle C1 and a line of direction to the corresponding target (azimuth bearing plane to the target).

By solving a system of equations compiled using the above mathematical relationships, the intersection points of the sphere and two planes are determined, which are possible locations of the target. Then, from two points according to criteria determined by the angle of the direction of the antenna to the target and the angle of deviation of the direction of the target from the direction of the antenna to the target, a point is selected that is the location of the target.

The disadvantage of the method and system for determining the coordinates of the target in the system "request-response" is the ability to accurately determine the coordinates of the target only if the direction of the Y axis of the NSC (in which the mathematical relation is set for the target height plane and the mathematical relation for the sphere of equal range) coincides with the direction of the Y axis of the local coordinate system (LSC) of the antenna (i.e., the coordinate system in which the deviation to the target from the direction of the antenna is measured, and the azimuth bearing plane to the target is set). The LSC antenna can coincide with the associated coordinate system (CCK, according to GOST 20058-80) - when the antenna is stationary relative to the carrier, or be its own, different from the connected, coordinate system - when the antenna is mobile relative to the carrier. When the pitch and (or) roll angles of the carrier in the NSC are other than zero, the Y axis of the NSC and the LSC do not coincide, which will inevitably lead to errors in determining the coordinates of the target.

One way to eliminate this drawback can be to obtain information about the current angular position of the antenna on the carrier and the carrier in space (i.e., the position of the coordinate axes of the coordinate systems LSC and NSC), then recalculate the position of the plane of the azimuth bearing from the LSC to the NSC using information about the current position of the coordinate axes of the coordinate systems, and finally, the calculation of the coordinates of the points of intersection of the azimuthal bearing plane, the target height plane and the sphere of equal range. In this case, there are no errors in determining the target coordinates associated with the use of coordinate values from different coordinate systems, since all the expressions used in the final calculation of the target coordinates (for the azimuth bearing plane, the target height plane and the sphere of equal range) are used coordinate values in the NSC. Information about the current position of the coordinate axes can be obtained from sensors included in the system under consideration or external (from the system media).

The technical result of the invention is to increase the accuracy of determining the coordinates of the target (responder) at any position of the interrogator antenna relative to the interrogator carrier and at any position of the interrogator carrier in space.

The technical result for the method is achieved in that the method for determining the coordinates of the target in the "request-response" system using an antenna having a given direction of aim allows combining at least three parameters that reflect the position of the target, the position of the antenna carrier and the direction of aiming of the antenna, as parameters, use the distance from the carrier to the target, the height of the target, the height of the carrier. Moreover, the method differs from the prototype in that the parameters additionally use the angular position of the carrier in space, the specified angular direction of the antenna to the target relative to the carrier, and the method includes the following steps in sequence:

- set the antenna in the direction of the target so that the response from the target is in the main lobe of the antenna pattern;

- receive response signals from the target using the “request-response” system and determine, using the CVC, using the mathematical description of the antenna bottom, the deviation of the direction of the response signals in the X0Z plane of the LCS from a predetermined direction uniquely defined in the LCS of the antenna;

- calculate the azimuthal direction to the target in the LSC antenna, using the specified direction uniquely defined in the LSC antenna and the deviation of the direction to the target;

- according to the calculated azimuthal direction to the target, the plane of the azimuthal bearing to the target in the LSC antenna is determined, perpendicular to the X0Z LSC plane;

- determine the plane of the azimuthal bearing to the target in the coordinate system of the NSC by recalculating the coordinates of three points or two vectors defined in the plane of the azimuthal bearing from the LSC antenna to the NSC;

- determine the target height plane in the NSC using the information about the target height received from the target using the request-response system and the sphere of equal range to the target using the target distance obtained by converting the time interval from issuing the request to receiving a response from the target;

- calculate the possible position of the target in the NSC, as the coordinates of the points of intersection of the azimuth bearing plane, the plane of the target height and the sphere of equal distance to the target;

- determine the angles between the target designation vector and each of the directions to the possible location of the target;

- make a selection of the location for which the specified angle is the least;

- the coordinates of the selected location will be the coordinates of the target.

The technical result of the system for determining the coordinates of the target in the system "request-response" is achieved by the fact that the system for determining the coordinates of the target in the system "request-response", placed on the carrier, includes an antenna directed to the target, the system "request-response", made with the possibility of comparing at least three parameters representing the position of the target, the position of the carrier and the direction of the antenna to determine the location of the target, a digital computing device (CVD) configured to calculate nate purpose in any position of the carrier and the antenna on the carrier, and a height sensor. Moreover, the first input-output of the system "request-response" is associated with an antenna aimed at the target. The second input-output of the system "request-response" is connected to the input-output of a digital computing device. The first input of the CVC is connected to the output of the height sensor. Moreover, the system differs from the prototype in that it further includes sensors of the angular position of the antenna directed to the target, and the second input of the CVC is connected to the output of the sensors of the angular position.

The sensors of the angular position of the antenna directed at the target track the direction uniquely determined in the LCS of the antenna (equal signal direction of the antenna bottom), i.e. measure the angular mismatches of the indicated direction in the azimuthal and elevation plane from the direction of the construction axis of the carrier and transmit the measured values to the CVC for use in the calculations.

The invention is illustrated by drawings Fig. 1 - FIG. 3 where

in FIG. 1 shows the local coordinate system (LSC) of the antenna;

in FIG. 2 shows a normal coordinate system (NSC) of a carrier;

in FIG. 3 shows a block diagram of a system for determining target coordinates in a request-response system.

In FIG. 1 (in LSC antennas) are presented:

- the X axis of _LSK , Y _LSK , Z _LSK of the coordinate system of LSK, whose origin coincides with the origin of the coordinate system of the NSK, whose axes X _NSK , Y _NSK , Z _{NSK are} also indicated in the figure. The X axis of the _{LSK is} always directed in the direction of radiation (in the direction of rotation) of the antenna perpendicular to the plane of its aperture, the Y axis of the _{LSK is} directed upward in the plane of the aperture of the antenna, the Z axis of the _LSK also lies in the plane of the aperture of the antenna so that the right axis forms with the X axis of the _LSK , Y _LSK rectangular coordinate system. The LSC coordinate system is rigidly connected to the antenna, therefore the axes of this coordinate system "rotate" with the antenna when the antenna is rotated on the carrier. Determining the direction of the target, due to the properties antenna pattern is always performed in the LCS, the antenna pattern is such as to determine the direction α at a target with a desired accuracy only in the X _LCS 0Z _LCS plane and does not allow to determine the direction to the target in the plane perpendicular to the plane X _LSK 0Z _LSK .

- circle K-1-C-2-L from the intersection of a sphere of the same range D from the carrier to the target with the azimuth bearing plane to the target in the LSC. The plane in which the circle lies is perpendicular to the X-axis of the _LSK 0Z _LSK in the LSK, and the Y-axis of the _LSK lies in the azimuth bearing plane;

- the location of the target C, located on a sphere of equal range D and, therefore, on the circle K-1-C-2-L;

- two vectors 01 and 02 lying in the plane of the azimuthal bearing to the target, the coordinates of the ends of which [X1_LSK, Y1_LSK, Z1_LSK; X2_LSK, Y2_LSK, Z2_LSK] together with the coordinates of their intersection points [0, 0, 0] form three points that completely determine the position of the bearing plane in space, with X1_LSK = X2_LSK = X_LSK and Z1_LSK = Z2_LSK = Z_LSK;

In FIG. 2 (in the NSC media) are presented:

- the local coordinate system (LSC) of the antenna and the normal coordinate system (LSC) of the carrier, the coordinates of the LSC and the NSC are the same, and the carrier is located at the origin of the NSC;

- circle K-1-C-2-L, lying in the plane of the azimuth bearing on the target (in LSC). The plane in which the indicated circle lies is generally not perpendicular to the XOZ plane of the NSC;

- two vectors 01 and 02 lying in the plane of the azimuthal bearing to the target, the coordinates of the ends of which [X1_NSK, Y1_NSK, Z1_NSK; X2_NSK, Y2_NSK, Z2_NSK] together with the coordinates of the points of their intersection [0, 0, 0] form three points that completely determine the position of the bearing plane in space;

- the circle A-C-B from the intersection of the plane of the same target height at _c = A-A _la with a sphere of the same range. The plane in which the circle lies is parallel to the X0Z plane of the NSC.

The method of determining the coordinates of the target in the system "request-response" is as follows.

1. When the cycles “Request media” - “Response to the target” are performed, the system determines the direction to the target in the azimuthal plane of the LSC (makes direction finding of the target in the azimuthal plane). The result of determining the direction to the target is the value of the angle α of the projection deviation (onto the plane X _LSC 0Z _LSC ) of the direction to the target from the axis 0X _LSC . In this case, due to the properties of the antenna pattern, determining the direction to the target in the elevation plane of the LSK is difficult or impossible. This means that the target can be located on the circle K-1-Ts-2-L in any place, mainly between vectors 1 and 2. In the process of executing the cycles “Media Request” - “Target Answer”, media queries of a certain type are used, answers to which contain information about the absolute height of the target. The absolute height of the medium is received from a height sensor mounted on the medium.

2. To obtain the expression of the azimuth bearing plane to the target in the NSC, necessary for calculating the coordinates of the target, two vectors 1 and 2 are formed, which belong to the azimuth bearing plane and begin at the beginning of the LSC coordinate system. For example, it can be a vector, limiting the useful radiation patterns in elevation sector antenna LCS plane and having the same magnitude and opposite in sign to the tilt plane X _LCS 0Z _BFV. Since the position of the azimuthal bearing plane depends only on the direction of the vectors, and does not depend on their length, vectors 1 and 2 of unit length can be used. For the width of the useful sector of the antenna radiation pattern (LH) of the antenna 60 ° in the elevation plane of the LSK, located symmetrically relative to the plane X _LSK 0Z _LSK , the coordinates of the ends of these vectors will be (the beginning of the vectors are located at the point with coordinates [0, 0, 0] ^T ):

Vectors 1 and 2 uniquely determine the azimuth bearing plane in any right-angled coordinate system, including the LSC and the NSC. To determine the azimuth bearing plane in another right-angled coordinate system, it is enough to convert the coordinates of the ends of these vectors from LSC to the desired coordinate system. Such a conversion from LSC to NSC can be performed, for example, in accordance with GOST 20058-80, by using the transformation matrix of the vector components:

The matrix of the transformation of the components of the vector, in turn, is formed by sequentially multiplying the matrices of “rotations” of the LSC coordinate system, reflecting the “rotation” of the LSC coordinate system by the angles of azimuthal and azimuthal displacement of the LSC relative to the NSC, by the roll, pitch and yaw angles of the SSC relative to the NSC (information on appropriate angles is received from the angular position sensors of the antenna mounted on the carrier):

where ψ, ϑ, γ, β, ε are the values of the rotations by the yaw, pitch and roll angles of the coordinate system of the SSC relative to the SSC, by the angles of the azimuthal and elevation offset of the SSC relative to the SSC, respectively.

3 Points of possible location of the target should simultaneously belong to:

- the plane of the azimuth bearing on the responding object;

- a sphere with a radius D of the same range to the target;

- planes of the same target height.

Mathematically, this is described by a system of equations:

Where:

- the first equation is the equation of the plane of the azimuth bearing in the coordinate system of the NSC, in matrix form;

- the second equation is the equation of a sphere of the same range to the target in the coordinate system of the NSC;

- the third equation is the equation of the plane of the same target height relative to the carrier in the coordinate system of the NSC.

Given the fact that [X0_NSK; Y0_NSK; Z0_NSK] = [0; 0; 0], and after changing variables

h = A-A _LA

the system of equations takes the form:

It can be shown that the solution to this system of equations will be the coordinates of the possible locations T1, T2 of the target:

4. The selection of one of the two possible locations of the target is carried out according to a given criterion, for example, according to the least deviation of the direction to the target from the direction of the antenna’s turn (from the direction of target designation). The direction of the target designation can be set initially, or it can be determined (as the direction of the antenna’s turn) on the basis of the assumption that the direction of the antenna’s turn is the direction of the X-axis axis vector of _LSC having coordinates [1, 0, 0] ^T in the LSC. In the second case, the coordinates of the vector of the direction of rotation of the antenna from the LSC to the NSC are recalculated using the matrix of the transformation of the components of the vector, the converted coordinates of the vector are taken as the coordinates of the direction vector of the target designation:

The angles between two vectors (direction of target designation and directions to a possible target location) are determined, for example, by calculating the cosines of these angles using the formula (derived from the formula for the scalar product of vectors):

- угол между вектором целеуказания и направлением на i-e местоположение цели и координаты i-го местоположения цели соответственно.Where

- the angle between the targeting vector and the direction to ie the location of the target and the coordinates of the i-th target location, respectively.

After determining the angles between the targeting vector and each of the directions to the possible locations of the target, the selection is made of the location for which the specified angle has the smallest value. The coordinates of the selected location will be the coordinates of the target.

The system for determining the coordinates of the target in the request-response system (Fig. 3), placed on the carrier 1, includes an antenna 2 directed to the target, a request-response system 3, configured to match at least three parameters, representing the position of the target, the position of the carrier and the direction of the antenna to determine the location of the target, as well as digital computing device 4 (DAC) (in the particular case it can be an integral part of the request-response system), configured to calculate the coordinates of the target position of the vehicle and an antenna on a support, the height sensor 5 and an angular position sensor 6, the antenna directed at the target. In this case, the first input-output of the system "request-response" 3 is connected with the antenna 2, aimed at the target. The second input-output of the system "request-response" 3 is connected to the input-output of a digital computing device 4. The first input of the DAC 4 is connected to the output of the height sensor 5. The second input of the DAC 4 is connected to the output of the angle sensors 6.

The system for determining the coordinates of the target in the system "request-response" works as follows.

- expands the antenna (or carrier with the antenna if the antenna is stationary relative to the carrier) in the direction of the target so that the response from the target appears in the main lobe of the antenna pattern;

- during the execution of the “Request from the carrier - Response from the target” cycles, the system receives response signals from the target and, using the DAC, using the mathematical description of the antenna’s bottom, determines the deviation of the direction of the response signals in the X0Z plane of the LSK (in the plane of the yaw angle in the LSK) from some a given direction (for example, from the equal-signal direction of the antenna pattern), uniquely determined in the LSC antenna;

- the system using the CVC determines the target’s height plane in the NSC using the information about the target’s height and the sphere of equal range to the target using the range to the target obtained by converting the time interval from issuing a request to receiving a response from the target;

- based on the calculated azimuthal direction (yaw angle) to the target, using the CVC, the system determines the azimuthal bearing plane to the target in the LCS antenna, perpendicular to the X0Z LSK plane (i.e., the plane that simultaneously belongs to the Y axis of the LCS and the direction vector to the target in LSK). The plane of the azimuthal bearing to the target in the LSC antenna is determined by setting two vectors that intersect at the origin and are oriented so that their azimuthal coordinates in the LSC antenna are the same, and the values of the Y coordinates in the LSC are opposite. The length of the vectors can be taken either equal to the distance to the target, measured during the execution of the cycles "Request from the carrier - Response from the target", or taken equal to one;

- the system using the CVC determines the azimuth bearing plane to the target in the coordinate system of the NSC by recalculating the coordinates of the previously defined vectors from the LSC antenna to the NSC using, for example, the matrix M _{LSK → NSK of} transforming the components of the vector (according to GOST 20058-80). When calculating the transformation matrix of the vector components, the yaw, pitch and roll of the carrier from sensors that determine the position of the carrier, and the yaw, pitch and roll of the given antenna direction (for example, an equal-signal direction) on the carrier are used:

the system finds solutions to a set of mathematical equations

и

в НСК возможных положений Т1 и Т2 цели в пространстве;representing coordinates

and

in the NSC of possible positions of T1 and T2 targets in space;

- from the solutions found (at most - two solutions), the system selects one that satisfies the condition of minimum deviation of the target’s position in space from a given direction (for example, from the direction of target designation, or from the direction in which the antenna is installed), by determining the angles between the directions to the target position in space and in a given direction, with subsequent selection of a direction for which the deviation angle is minimal:

Thus, improving the accuracy of determining the coordinates of the target (responder) at any position of the interrogator’s antenna relative to the interrogator’s carrier and at any position of the interrogator’s carrier in space is carried out by obtaining information from the angular position sensors about the current angular position of the antenna on the carrier and the carrier in space (about the position of the axes coordinate system coordinate system LSC and NSC), recalculation of the position of the azimuth bearing plane from LSC to NSC using information about the current position of the coordinate axes of rdinatnyh systems, and calculating coordinates of the intersection points of the plane azimuth bearing, and the plane of the target height range equal to the scope.

Claims (2)

1. The method of determining the coordinates of the target in the system "request-response" using an antenna having a given direction of aiming, and combining at least three parameters that reflect the position of the target, the position of the antenna carrier and the direction of aiming of the antenna, and the distance from of the carrier to the target, the height of the target, the height of the carrier, characterized in that the parameters further use the angular position of the carrier in space and the specified angular direction of the antenna to the target of the relative but the carrier, the method includes the following sequentially carried out steps: install the antenna in the direction of the target so that the response from the target appears in the main lobe of the antenna pattern; receive response signals from the target using the “request-response” system and determine using the digital computing device (CVD), using the mathematical description of the antenna radiation pattern (LH), the deviation of the direction of the response signals in the X0Z plane of the local coordinate system (LSC) from some given directions uniquely defined in the LSC antenna; calculate the azimuthal direction to the target in the LSC antenna, using the specified direction uniquely defined in the LSC antenna and the deviation of the direction to the target; from the calculated azimuthal direction to the target, determine the plane of the azimuthal bearing to the target in the LSC antenna perpendicular to the plane X0Z LSC; determine the plane of the azimuthal bearing to the target in the normal coordinate system (NSC) by recalculating the coordinates of three points or two vectors specified in the plane of the azimuthal bearing from the LSC antenna to the NSC; determining the target height plane in the NSC using the information about the target height obtained from the target using the request-response system and the sphere of equal range to the target using the target distance obtained by converting the time interval from issuing the request to receiving a response from the target; calculate the possible position of the target in the NSC, as the coordinates of the intersection points of the azimuth bearing plane, the plane of the target height and the sphere equal to the distance to the target; determine the angles between the target designation vector and each of the directions to the possible locations of the target; selecting a location for which the specified angle is the least; the coordinates of the selected location will be the coordinates of the target. 2. The system for determining the coordinates of the target in the system "request-response", placed on the carrier, including the antenna directed to the target, the system "request-response", configured to match at least three parameters representing the position of the target, the position of the carrier and the direction of the antenna to determine the location of the target, as well as a digital computing device (DAC), configured to calculate the coordinates of the target at any position of the carrier and antenna on the carrier, the height sensor, and the first input the output of the request-response system is connected to the antenna aimed at the target, the second input-output of the request-response system is connected to the input-output of a digital computing device, the first input of the CVC is connected to the output of the height sensor, characterized in that it further includes sensors the angular position of the antenna aimed at the target, while the second input of the CVC is connected to the output of the angular position sensors.

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