RU2791981C2 - Method for dynamic adjustment of antenna array with electronic scanning of ship radar station - Google Patents

Abstract

FIELD: radiolocation.

SUBSTANCE: invention relates to the field of radiolocation for adjustment of antenna arrays (hereinafter – AA). At a distance from a ship, on a stationary base, a radiation source (hereinafter – RS) is installed, operating at a frequency of a radar station (hereinafter – RS), which operates for reception, and geodesic coordinates of RS are determined using user navigation equipment. On the ship, using an onboard inertial navigation system (hereinafter – OINS), geodesic coordinates of the ship are measured: current longitude, latitude, and altitude above the ellipsoid of a ship central control platform (hereinafter – CCP), as well as coordinates of its position: course, trim, and roll angles. During adjustment, the ship is turned to RS so that a direction to RS passes along the course angle of a viewing sector of the adjusted AA. The main petal of a directional diagram of the adjusted AA should accompany the direction to RS when it is in the viewing sector of AA. During turning, all listed ship coordinates are simultaneously measured using OINS and azimuth, and an angle of RS place in ACS of the adjusted AA. By data of each set of simultaneous measurements, rectangular coordinates of RS radius vector are calculated in an intermediate axis system (hereinafter – IAS) associated with CCP. Coordinates are recalculated in SCS1 as SCS, a center of which is transferred from CCP to a center of ACS of the adjusted AA. By radar measurements of azimuth and the angle of RS place in ACS of AA, from the same set, and taking into account a length of RS radius vector in SCS1, rectangular coordinates of RS radius vector in ACS are calculated. Target three angles of installation of the adjusted AA on the ship, included in a system of equations of connection of rectangular RS coordinates in ACS and in SCS1 are determined by using step-by-step approximate methods for calculation by pairs of sets, followed by averaging, or non-linear filtration methods.

EFFECT: dynamic adjustment of AA with electronic scanning of a ship RS in conditions of sea confusion.

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Description

The invention relates to the field of shipborne radar.

The essence of the invention is the dynamic adjustment of the antenna array (AR) with electronic scanning of the ship's radar station (RLS) as the determination of the three angles of the installation of the AR on the ship: azimuth, elevation and twisting angle of the AR electric axis in the associated coordinate system (SSK according to GOST 20058-80) in sea conditions.

This goal is achieved as follows (Fig. 1):

at a sufficient, from the point of view of the alignment accuracy, distance from the ship, a radiation source (IS) operating at the frequency of the radar is installed, and its geodetic coordinates are accurately determined;

during adjustment, the turn of the ship in relation to the AI is changed in any way possible in the entire scanning sector of the AR along the heading angle;

using an onboard inertial navigation system that receives signals from navigation satellites, the current navigational data of the ship are constantly measured (geodetic coordinates of the ship's center of mass (SMC), as well as its position angles: heading, trim and roll);

according to the AI signals received by the AR, the current azimuth and elevation angle of the AI in the AR (ASC) coordinate system are measured, according to which, using the rectangular coordinates of the AR center (the origin of the ASC) in the SSC (the origin is in the CSC), the geodetic coordinates of the AI and the current ship navigation data, the current range of the AI from the center of the AR is calculated and the current rectangular coordinates of the AI in the ASC are determined;

based on the geodetic coordinates of the AI and the current geodetic coordinates of the CMC, the current rectangular coordinates of the radius vector of the AI in a non-rotating semi-coupled CS with the origin in the CMC are calculated, which are then recalculated into the CCS1 (CSC with the origin shifted from the CMC to the center of the AR) using the position angles of the ship and rectangular coordinates of the AR center in the SSC;

the required three angles of the installation of the AR on the ship, which are non-linearly included in the system of equations for the connection of the rectangular coordinates of the AI in the ASC and in the SSC1, are determined from the entire set of measurements by a suitable computational method.

The method can be used to align the electrical axis of any AR, rigidly mounted on movable carriers, with increased requirements for the accuracy of the AR beam setting. Applicable for alignment of a shipborne radar, which has several simultaneously operating radars.

Most of the known methods of antenna alignment [1, 2] assume the immobility of the adjusted antenna. Ensuring this requirement for a ship's AR requires the immobilization of the ship and is therefore associated with many difficulties. Shipborne radars with high-precision AR beam setting must undergo regular verification, because an unaccounted for angular change in the position of the AR on the ship during its operation, even by a few arc minutes, may be unacceptable. Therefore, the main requirement for mounting the AR is strength, assuming that errors in the angles of installation of the electrical axis of the AR can be separately measured and taken into account. Therefore, the method for adjusting the AA should allow it to be carried out at any location of the ship and not require expensive additional equipment.

Errors in the installation angles of the AR are important components of the systematic errors in measuring the angles of objects. Unlike systematic errors due to errors in the amplitude-phase distribution on the AR and significantly different for different directions, errors in three installation angles are parametrically included in the equations for recalculating the coordinates of an object from the ACS to a non-rotating semi-coupled CS of the ship and, being measured, can be easily mathematically taken into account .

The method of aligning the radar antenna closest in terms of the set of features is described in the description of patent RU2527939 [3]. In it, the high accuracy of the radar antenna alignment is based on knowing the coordinates of the antenna being adjusted and the reflecting object using signals from navigation satellites (errors in units of meters). Angular corrections are determined based on a comparison of the object's position coordinates obtained in two ways: by measurement and by calculation. The implementation of this method of alignment involves the use of a flying object with a satellite navigator installed on it, as well as a radio transmitter, with the help of which data of its current location could be transmitted to the radar from an airborne object. The object must have sufficient RCS so that at a distance of several kilometers the random error in measuring its angular coordinates with the help of radar is small. As indicated in [4]: “measurements by the flyby method using manned aircraft are associated with great organizational and technical difficulties in conducting the experiment ... The low level of automation of processing the results made the flyby method one of the most expensive and technically complex.” The adjustment method described in the description of patent RU2527939 indicates the steps for determining errors in azimuth and, by analogy, can be used to determine errors in elevation, but does not apply to determining the angle of twist of the antenna.

The proposed method is as accurate as the flight method, but simpler and cheaper in relation to the task of aligning a ship's radar. The method does not require: a controlled flying object, the current measurement of navigation data on it, their transmission via radio communication to the radar. The only additional equipment of the proposed method is an AI operating at the frequency of the radar, which must be fixedly installed at a distance that ensures the smallness of positioning errors on navigation satellites compared to the allowable errors in measuring the angles of the aligned radar, and with the lowest elevation above sea level to ensure the minimum impact of multipath propagation of radio waves on the accuracy of measuring the elevation angle due to reflections from the water surface. When using AI, it is easier to provide a higher level of the received signal, from which the radar determines the angular coordinates of the object, and, consequently, a higher measurement accuracy than with active radar. The high-precision determination of the ship's navigational data is carried out using standard on-board navigation equipment. The presence of data on the position of the ship, taken into account in the calculations, does not require measures to immobilize it and allows you to adjust the ship's radar in conditions of sea waves. The ship must be close to a piece of land that is suitable for AI installation on it. During the adjustment, the turn of the ship should be provided: under its own power in a circle, with the help of a pulling or pushing tug, or in another way. During the turn of the ship, the direction to the AI must pass the entire scanning range of the AR along the heading angle, and the radar must be within the main lobe of the AI antenna.

The calculation of the angles of installation of the AR on the ship (azimuth, elevation and angle of twisting of the AR normal in the SSC) is based on the following. Based on the measurements and recalculations of coordinates described above, there are two sets of rectangular coordinates of the AI: 1) in SSK1 (SSK, the origin of which is transferred from the CMC to the origin of the ASC), 2) and in the ASC. Recalculation of the first coordinates into the second ones is performed by multiplying by the rotation matrix AR from the initial position to the final one.

.

.

), угол места (

) и угол скручивания (

), которые математически подобны трём последовательным поворотам на углы рыскания, тангажа и крена по ГОСТ 20058-80. Матрица

вычисляется, согласно п.1.1 Приложения 2 указанного ГОСТ [5]: In the initial position of the AR, the origin of the ASC associated with the AR is determined by rectangular coordinates in the SSC, and the directions of the ASC axes coincide with the directions of the axes of the same name of the SSC1. To transfer the AR to the final position, three successive turns are performed (Fig. 2): by the azimuth angle (

), elevation angle (

) and twist angle (

), which are mathematically similar to three successive turns by yaw, pitch and roll angles according to GOST 20058-80. Matrix

is calculated according to clause 1.1 of Appendix 2 of the specified GOST [5]:

.

.

, относительно углов

,

и

, нелинейно входящих параметрами в элементы матрицы. Но задача определения этих трёх углов из данной системы трёх нелинейных уравнений имеет бесконечное множество решений, т.к. задание направления на ИИ имеет две угловые степени свободы, а положение АР имеет три угловые степени свободы. Это означает, что требуется, по меньше мере, ещё одна пара прямоугольных координат ИИ (в ССК1 и в АСК), полученная для отличающегося по курсу положения корабля по отношению к ИИ. Для достижения наибольшей точности при усреднении в условиях ошибок установки главного луча ДН АР с электронным сканированием и влияния элементов корпуса корабля нужно сделать много измерений при различных курсах корабля, а затем по всей совокупности данных определить искомые углы установки АР на корабле.The way to calculate the installation angles of the AR on the ship is to solve a system of equations that relate the available rectangular coordinates of the AI in SCK1 and ASC through the conversion matrix

, relative to the angles

,

And

, which are non-linear parameters in the elements of the matrix. But the problem of determining these three angles from a given system of three nonlinear equations has an infinite number of solutions, because setting the direction to the AI has two angular degrees of freedom, and the position of the AR has three angular degrees of freedom. This means that at least one more pair of AI rectangular coordinates (in SSK1 and in ASC) is required, obtained for the position of the ship with respect to the AI that differs in course. To achieve the highest accuracy when averaging under the conditions of errors in the installation of the main beam of the AP AR with electronic scanning and the influence of the elements of the ship's hull, it is necessary to make many measurements at various ship courses, and then, using the entire set of data, determine the desired angles of the AR installation on the ship.

Information sources

1. Zakhariev L.N., Lemansky A.A., Turchin V.I. and other Methods for measuring the characteristics of microwave antennas. Edited by N.M. Zeitlin. - M., Radio and communication, 1985, 114 p.

2. Vasin V.V., Vlasov O.V., Grigorin-Ryabov V.V. etc. Radar devices. - M., Soviet radio, 1970, 27 p.

3. Savvateev V.S., Sukhov V.V. OJSC GSKB Almaz-Antey. A method for adjusting radar stations. Patent No. 2527939 RF, IPC G01S 7/40 (2006.01); dec. 11/15/2012; publ. 09/10/2014, Bull. No. 25. (URL: http://www.freepatent.ru/patents/2527939 - accessed 07/10/2021).

4. Prosvirkin I.A. Flight method for measuring the radiation patterns of large-aperture antennas using an unmanned aerial vehicle and the GLONASS system / Abstract of the dissertation for the competition of the academic st. Ph.D. 2019. (URL: https://www.dissercat.com/content/obletnyi-metod-izmereniya-diagramm-napravlennosti-krupnoaperturnykh-antenn-s-ispolzovaniem – accessed 10.07.2021).

5. GOST 20058-80 Dynamics of aircraft in the atmosphere. Terms, definitions and designations. (URL: https://docs.cntd.ru/document/1200009362 – accessed 07/10/2021).

Claims (1)

A method for dynamically adjusting a fixed antenna array (AR) of a shipborne radar station (RLS) or each of several simultaneously operating ARs as part of a ship's all-round radar as determining three installation angles of the adjusted AR on a ship: azimuth, elevation and twisting angle of the AR electric axis in linked coordinate system (CCS), which consists in measuring the latitude, longitude and height of the position of the radiation source (IS) operating at the frequency of the radar, simultaneously measuring the latitude, longitude and altitude of the central control platform of the ship (CCP), heading angles, trim and roll of the ship and azimuth and elevation angle of the AI in the antenna coordinate system (ASC) of the adjusted AR, characterized in that the AI is installed motionless with a decrease in the influence of multipath signal propagation in the direction of the radar, the radar works for reception, the ship turns so that the direction to the AI passes along the heading angle sector review of the adjusted AR, during the turn, sequences are obtained multiple sets of simultaneous measurements of all the listed coordinates of the ship and the azimuth and elevation angle of the AI in the ASC AR, the rectangular coordinates of the AI obtained for each set of latitude, longitude and altitude of the AI and the latitude, longitude and altitude of the ship are recalculated from a semi-coupled coordinate system with the origin in the CCT in SSK1 as SSK, transferred to the origin of the ASC AR, by the values of the azimuth and elevation angle of the AI in the ASC from the same set of simultaneous measurements and based on the radius vector of the AI in the SSC1, the rectangular coordinates of the AI in the ASC are calculated, the values of three angles are calculated by step-by-step mathematical methods AR settings on the ship, such that best approximate the expressions for the relationship between the rectangular coordinates of the AI in SCK1 and in the ASC AR, non-linearly containing the installation angles as parameters, to the correct equalities immediately for all sets of simultaneous measurements of the listed ship coordinates and the azimuth and elevation angle of the AI in the ASC of the adjusted AR.

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