Method of determining and delivery of coordinate information to consumers in secondary radar location system

Abstract

FIELD: secondary radar location.SUBSTANCE: invention which and can be used in secondary radar systems (SRS), each of which is formed by a combination of a radar interrogator and a number of on-board transponders placed on mobile objects. In the SRS, the determination of the coordinates of the transponders (moving objects carrying the transponders) is carried out and the delivery of coordinate information to consumers - the control point interacting with the interrogator and the on-board equipment of the moving object interfaced with the transponder. In the claimed method, a directional antenna with a high-speed setting of the azimuthal position of the directional pattern lobes is used in the SRS interrogator. When performing radar soundings, in addition to interrogation and response messages, coordinate messages are also used; for each sounding in the interrogator, the information of the transmitted interrogation message includes the coordinates of the interrogator, the sounding azimuth, the parameters of the transmitting direction-finding characteristic, and the structure of the message includes the main and additional synchronization signals, each of which is emitted at its own azimuthal position of the lobe of the transmitting diagram, and the lobes in both positions intersect and are symmetrical relative to the sounding azimuth. In the transponder, based on the received synchronization signals, a quasi-monopulse measurement of the azimuth of the transponder is carried out, a response packet is formed and transmitted, which contains the altitude of the transponder and the measured azimuth value. In the interrogator, using the synchronization signal of each received response message, a range measurement and a monopulse measurement of the azimuth of the responder are performed, the received and measured azimuth values are jointly processed, and a refined azimuth estimate, range estimate, and altitude are transmitted to the interacting control point. In the interrogator, provided that at least one response message is received, a coordinate message is formed and emitted, the information of which includes the values of the azimuth and range of the responder measured in the interrogator, and in the structure - two synchronization signals emitted similarly to the emission of synchronization signals of the interrogation message. In the transponder, based on the received synchronization signals, a quasi-monopulse measurement of the azimuth of the transponder is repeated, the range of the transponder relative to the interrogator is measured, the results of three azimuth measurements and two range measurements are jointly processed, and a generalized estimate of the azimuth and range, together with the coordinates of the interrogator, is transmitted to the interfaced onboard equipment.EFFECT: increasing the accuracy of coordinate information determined in the VRS and delivered to consumers.1 cl, 5 dwg

Description

[0001] Field of technology to which the invention relates

[0002] The invention relates to the field of secondary radar and can be used in secondary radar systems (SRS) for monitoring moving objects - air, surface, ground.

[0003] The VRS includes a radar interrogator and a set of on-board responders located on mobile objects.

[0004] The VRS is, as a rule, a link in an automated control system (ACS) of mobile objects, in which the VRS interrogator interacts with the ACS control point, and each responder is interfaced with the on-board control equipment of the host object.

[0005] One of the main functions of the VRS is to determine the coordinates of the responders (moving objects equipped with responders) and deliver the coordinate information to consumers, which are:

[0006] - an automated control system control point interacting with the VRS interrogator, consuming coordinate information about all mobile objects (their responders) observed by the VRS;

[0007] - on-board equipment of each mobile object monitored by the VRS, interfaced with the VRS transponder, consuming information about its own current coordinates (the coordinates of the transponder).

[0008] Technology Level

[0009] Determination and delivery of coordinate information to consumers in the VRS can be carried out in several known ways [1, …, 4].

[0010] A method for determining and delivering coordinates in a secondary radar system is known [1], which we will define as an analog method. The analog method consists of the following:

[0011] The secondary radar system includes an interrogator and a set of responders placed on mobile objects,

[0012] Each defendant is assigned an individual address and this address is entered into the defendant;

[0013] The interrogator uses a directional antenna, while the responder uses an omnidirectional transmitting and receiving antenna;

[0014] in the interrogator, a periodic survey of the space is carried out, for which a sequence of radar soundings is carried out at different angular positions of the main lobe of the interrogator antenna radiation pattern;

[0015] during probing, a radar request-response is carried out, for which:

[0016] - the interrogator emits a common interrogation signal, which is received by each responder that receives it,

[0017] - the transponder receives the incoming general interrogation signal, emits a general response signal, the same for all transponders, and an information block containing the individual address of the transponder, the flight altitude of the mobile object carrying the transponder, and other flight information,

[0018] - the interrogator receives and processes each incoming general response signal with an information block, and based on the processing results, the individual address and current coordinates of the responder are determined;

[0019] Send the data obtained during probing to the interrogator output for transmission to the control center interacting with the interrogator.

[0020] This method allows the determination of coordinates and individual addresses of transponders (moving objects equipped with transponders) in the interrogator of the secondary radar system and the delivery of coordinate and address information to the ACS control center, but does not ensure the delivery of coordinate information to the on-board equipment of the corresponding moving objects.

[0021] The closest to the claimed method is the method of determining and delivering coordinate information to consumers in a secondary radar system [2, 3, 4], adopted as a prototype method and consisting of the following:

[0022] The secondary radar system includes a monopulse interrogator and a set of responders placed on moving objects;

[0023] Each defendant is assigned an individual address; to contact multiple defendants, a general address is used; each defendant is assigned an individual and general address;

[0024] The interrogator uses a directional antenna rotating around a vertical axis with single-lobe radiation patterns - two receiving lobes, the lobes of which intersect and together form a monopulse pair, and one transmitting lobe, the axis of the lobe of which coincides with the axis of symmetry of the monopulse pair;

[0025] Taking into account the shape of the monopulse pair in the interrogator, a receiving direction-finding characteristic is formed;

[0026] The transponder uses an omnidirectional transmitting and receiving antenna;

[0027] The interrogator organizes periodic space surveys by performing radar soundings using interrogation and response packets;

[0028] The structure of the request packet includes the synchronization signal A and the request information block, and the basic information composition includes the individual address of the requested responder or the general address;

[0029] The structure of the response packet includes the R synchronization signal and the response information block; the basic information composition includes the individual address of the responder and the flight altitude of the mobile object carrying the responder;

[0030] in the interrogator, for each radar sounding, the sounding azimuth and the maximum sounding range are determined;

[0031] on radar sounding:

[0032] - in the interrogator, a query message is formed and, when the axis of the transmitting diagram petal is oriented in the direction of the probing azimuth, a query message is transmitted,

[0033] - each responder that has received the request message sends the data received in the request information block to the interfaced on-board equipment of the mobile object, forms and transmits a response message,

[0034] - in the requester upon receipt of the received reply parcel:

[0035] extract the individual address of the defendant and the height from the parcel,

[0036] based on the delay time of the synchronization signal R of the response packet relative to the synchronization signal A of the request packet, the range of the responder is estimated,

[0037] According to the ratio of the amplitudes of the synchronization signal R received through each of the petals of the monopulse pair, the parameters of the receiving direction-finding characteristic and the value of the probing azimuth, a monopulse estimate of the azimuth of the responder is performed,

[0038] send the individual address of the responder, the altitude, the range estimate and the azimuth estimate to the interrogator output for transmission to the control center interacting with the interrogator;

[0039] The interrogator completes radar probing after the time for possible receipt and reception of a response message from the maximum probing range has elapsed and moves on to the next probing.

[0040] Figure 1 illustrates a cyclogram of the radar probing process in the prototype method. For illustration purposes, three transponders are located within the interrogator's antenna beam during probing.

[0041] At the beginning of probing, the interrogator emits a query packet consisting of a synchronization signal A and an information block (Fig. 1, diagram a).

[0042] Each of the responders, having received and processed the request message, forms and emits a response message consisting of a synchronization signal R and an information block (Fig. 1, diagrams b, c, d).

[0043] The specified response parcels are received and processed in the requester (Fig. 1, diagram a).

[0044] As a result of processing the interrogation packet with the interrogation information block in the responder, the received data is extracted from it and transmitted to the interfaced on-board equipment of the mobile object, which may contain coordinate information about the location of this responder obtained in the interrogator during previous probing.

[0045] As a result of processing each response parcel with a response information block in the requester:

[0046] - the received data, including the individual address of the responder and its altitude, are extracted from it and transmitted to the interacting control point (ICP);

[0047] - the time delay between the moment of emission of the synchronization signal A of the request packet and the moment of reception of the synchronization signal R of the response packet is used to measure the range to the responder;

[0048] - using the known procedure of monopulse reception (see, for example, [5], § 5.17), measure the amplitudes of the synchronization signal R received in the channels of each of the receiving directional patterns, and, based on their difference and the receiving direction-finding characteristic, determine the sign and magnitude of the deviation of the azimuth of the transponder from the probing azimuth; by summing the deviation and the probing azimuth, obtain an estimate of the azimuth of the transponder;

[0049] - estimates of the range and azimuth of the responder are transmitted to the VPU.

[0050] The prototype method, like the analogous method, allows for determining the coordinates and individual addresses of transponders (moving objects equipped with transponders) in the interrogator of a secondary radar system and delivering coordinate and address information to one of the consumers - the interacting ACS control point.

[0051] Due to the presence of information blocks in the interrogation packets, the prototype method, unlike the analog method, allows for the delivery of coordinate information also to another consumer - the on-board equipment of the mobile object interfaced with the responder.

[0052] At the same time, the prototype method has a drawback, which is the relatively low accuracy of determining and delivering coordinate information to consumers, which is predetermined by two factors.

[0053] The first factor is determined by the nature of the linear error in estimating the azimuth of the responder in the interrogator.

[0054] The monopulse azimuth estimate is performed in the interrogator in angular units. The error in this estimate is a random variable, typically with a zero mathematical expectation and a root-mean-square value of 4-7 arcminutes, practically independent of range.

[0055] To determine the boundaries of the error spread ellipsoid, the user needs to convert the angular error of the azimuth estimate from angular units to linear units using the formula:

[0056]

[0057] where D is the range of the responder relative to the interrogator,

[0058] σ ау - root mean square error in angular units,

[0059] σ ал - root mean square error in linear units.

[0060] As can be seen from formula (1), the linear error σ ал increases proportionally to the increase in range D. For example, with the standard standard for VRS standard standard error of azimuth estimation in angular units σ ау ,=4' and range D=40 km error in linear units σ ал turns out to be relatively acceptable and equal to 47 m, but when the range increases to 400 km, the error increases to an unacceptable 468 m.

[0061] Another factor is determined by the presence of a delay between the moment of measurement of coordinates in the interrogator during radar probing and the moment of delivery of coordinate information to the on-board equipment interfaced with the responder during one of the subsequent probings.

[0062] The delay can range from the duration of radar sounding (usually 3-5 ms), if transmission can be carried out during the nearest sounding, to the duration of the survey (usually 10 s) when the interrogator is loaded or the moving object is maneuvering in azimuth.

[0063] Due to the movement of the moving object during the delay, an additional error in the position estimate occurs, which is random for the user. Specifically, in the above-mentioned delay range of 3-4 ms to 10 s and at a moving object speed of up to 300 m / s, the error can range from 1 m to 3000 m.

[0064] Disclosure of the essence of the invention

[0065] The aim of the invention is to increase the accuracy of estimating the coordinates of moving objects determined in a secondary radar system and delivered to consumers.

[0066] To achieve the said objective, a known method for determining and delivering coordinate information to consumers in a secondary radar system consists in the fact that:

[0067] The secondary radar system includes a monopulse interrogator and a set of responders placed on moving objects;

[0068] Each defendant is assigned an individual address; to contact multiple defendants, a common address is used; each defendant is assigned an individual and common address;

[0069] The interrogator uses a directional antenna with single-lobe radiation patterns - two receiving lobes, the lobes of which intersect and together form a monopulse pair, and one transmitting lobe;

[0070] Taking into account the shape of the monopulse pair in the interrogator, a receiving direction-finding characteristic is formed;

[0071] The transponder uses an omnidirectional transmitting and receiving antenna;

[0072] The interrogator organizes periodic space surveys by performing radar soundings using interrogation and response packets;

[0073] The structure of the request packet includes the synchronization signal A and the request information block, and the basic information composition includes the individual address of the requested responder or the general address;

[0074] The structure of the response packet includes the R synchronization signal and the response information block; the basic information composition includes the individual address of the responder and the flight altitude of the mobile object carrying the responder;

[0075] In the interrogator, for each radar sounding, the sounding azimuth and the maximum sounding range are determined;

[0076] on radar sounding:

[0077] - in the requester, a request package is formed and transmitted,

[0078] - each responder that has received the request message sends the data received in the request information block to the interfaced on-board equipment of the mobile object, forms and transmits a response message,

[0079] - in the requester upon receipt of the received reply parcel:

[0080] extract the individual address of the defendant and the height from the parcel,

[0081] based on the delay time of the synchronization signal R of the response packet relative to the synchronization signal A of the request packet, the range of the responder is estimated,

[0082] According to the ratio of the amplitudes of the synchronization signal R received through each of the petals of the monopulse pair, the parameters of the receiving direction-finding characteristic and the value of the probing azimuth, a monopulse estimate of the azimuth of the transponder is performed,

[0083] sends the individual address of the responder, the altitude and the range estimate to the interrogator output for transmission to the control center interacting with the interrogator;

[0084] in the interrogator, radar sounding is completed and the next sounding is started,

[0085] It is proposed to introduce the following additional sequence of actions:

[0086] The interrogator uses an antenna with a fast-acting setting of the azimuth position of the directional pattern lobes;

[0087] In addition to the sync signal A, the sync signal B is included in the structure of the request packet;

[0088] To perform radar soundings, in addition to the request and response packets, a coordinate packet is also used as part of the C synchronization signal, the D synchronization signal, and the coordinate information block; a general or individual address is included in the basic information composition;

[0089] a monopulse pair of intersecting lobes and a receiving direction-finding characteristic are formed in the interrogator for each radar sounding, and the axis of symmetry of the monopulse pair is oriented in the direction of the sounding azimuth;

[0090] in the interrogator for each radar sounding, in addition:

[0091] - determine the azimuths P and S, when successively installing the lobe of the transmitting directional pattern in the direction of which, a quasi-monopulse pair of intersecting lobes is formed, symmetrical with respect to the probing azimuth,

[0092] taking into account the shape of the quasi-monopulse pair, a transmitting direction-finding characteristic is formed,

[0093] - the request information block of the request package includes the coordinates of the interrogator, the sounding azimuth, the parameters of the transmitting direction-finding characteristic,

[0094] - define the probing cutoff moment as the moment of completion of the reception of a conditional response packet transmitted from the maximum probing range;

[0095] on radar sounding:

[0096] - in the interrogator, when transmitting the interrogation packet, the axis of the lobe of the transmitting directional pattern is set in the direction of azimuth P and the synchronization signal A is emitted, set in the direction of azimuth S and the synchronization signal B is emitted, set in the direction of the probing azimuth and the interrogation information block is emitted,

[0097] - in each responder that has received the interrogation message, based on the ratio of the amplitudes of the synchronization signals A and B, the parameters of the transmitting direction-finding characteristic and the value of the probing azimuth, a quasi-monopulse estimate of the azimuth of the responder relative to the interrogator is produced, this estimate is included in the response information block,

[0098] - in the requester upon receipt of each response parcel additionally:

[0099] carry out joint processing of the responder azimuth estimate made in the interrogator and the estimate received from the responder, form a refined responder azimuth estimate and include it in the data sent to the interrogator output,

[0100] defines the delay time in the interrogator from the moment of receiving the R synchronization signal of the response packet to the moment of probing cutoff,

[0101] fill out the responder form, including the individual address of the responder, the delay time in the interrogator, the azimuth estimate and the range estimate of the responder made in the interrogator;

[0102] - in the interrogator, if there is at least one response message received during probing, a coordinate message is formed and transmitted, for which:

[0103] The coordinate information block includes the defendants’ forms,

[0104] transmission of the coordinate package begins at the moment of sounding cutoff, during transmission, the lobe of the transmitting radiation pattern is set in the direction of azimuth P and the synchronization signal C is emitted, set in the direction of azimuth S and the synchronization signal D is emitted, set in the direction of the sounding azimuth and the coordinate information block is emitted;

[0105] In the interrogator, completion of radar sounding and transition to the next sounding is carried out by:

[0106] - in the absence of a coordinate package - at the moment of probing cutoff,

[0107] - if there is a coordinate parcel - at the moment of completion of its transmission;

[0108] in each respondent that received the coordinate parcel:

[0109] - extract from the coordinate information block the form with the individual address of this defendant,

[0110] - based on the delay time of the synchronization signal C of the coordinate package relative to the synchronization signal R of the response package, excluding the delay time in the interrogator, the range to the interrogator is estimated,

[0111] - based on the ratio of the amplitudes of the synchronization signal C and the synchronization signal D, a quasi-monopulse estimate of the azimuth of the responder relative to the interrogator is repeated,

[0112] - carry out joint processing of range estimates received from the interrogator and performed in the responder, azimuth estimates received from the interrogator and performed in the responder, form a generalized range and azimuth estimate,

[0113] - send a generalized estimate of the range and azimuth together with the coordinates of the interrogator to the mating on-board equipment of the moving object.

[0114] Brief description of drawings

[0115] Fig. 1 shows diagrams illustrating the cyclogram of the exchange of messages during the time interval of radar probing between the interrogator and three responders that were in the beam of the interrogator’s antenna during probing, when implementing the prototype method:

[0116] - diagram a - emission of a request packet, reception of response packets in the interrogator;

[0117] - diagrams b, c, d - reception of a request packet, emission of a response packet by the first, second and third responders, respectively.

[0118] Fig. 2 shows a functional diagram of a secondary radar system implementing the claimed method, consisting of a interrogator and one responder.

[0119] The following notations are introduced in Fig. 2.

[0120] 1 - requester;

[0121] 2 - defendant.

[0122] Contains requester 1:

[0123] 3 - information processing and technical management module;

[0124] 4 - interrogator antenna;

[0125] 5 - chart management module;

[0126] 6 - sync signal encoding module A;

[0127] 7 - sync signal encoding module B;

[0128] 8 - module for generating a request information block;

[0129] 9 - request information block encoding module;

[0130] 10 - sync signal encoding module C;

[0131] 11 - D sync signal encoding module;

[0132] 12 - module for forming coordinate information block;

[0133] 13 - module for coding the coordinate information block;

[0134] 14 - transmitter module;

[0135] 15 - receiving device module;

[0136] 16 - R sync signal decoding module;

[0137] 17 - response information block decoding module.

[0138] As part of defendant 2:

[0139] 18 - on-board antenna;

[0140] 19- on-board receiving device;

[0141] 20 - sync signal decoding module A;

[0142] 21 - sync signal decoding module B;

[0143] 22 - request information block decoding module;

[0144] 23 - sync signal decoding module C;

[0145] 24 - D sync signal decoding module;

[0146] 25 - coordinate information block decoding module;

[0147] 26 - azimuth measurement module;

[0148] 27 - range measurement module;

[0149] 28 - R sync signal encoding module;

[0150] 29 - response information block coding module;

[0151] 30 - on-board transmitting device;

[0152] 31 - on-board information processing and interfacing module.

[0153] Fig. 3 shows diagrams illustrating the cyclogram of the exchange of messages during the time interval of radar probing by the interrogator of three responders that were in the beam of the interrogator's antenna during probing, when implementing the proposed method:

[0154] - diagram a - emission of a request packet, reception of response packets and emission of a coordinate packet in the interrogator;

[0155] - diagrams b, c, d - reception of a request message, emission of a response message and reception of a coordinate message by the first, second and third responders, respectively.

[0156] Fig. 4 shows interrogator 1, responder 2, the azimuth of the responder relative to the interrogator is marked and the positions of the interrogator antenna beam oriented in the direction of the probing azimuth, the leading azimuth P and the following azimuth S are given.

[0157] Fig. 5 shows interrogator 1, responder 2, the angular position of the interrogator antenna beam is marked when emitting synchronization signal A of the interrogation package and when emitting synchronization signal C of the coordinate package (Fig. 5-A), the angular position of the interrogator antenna beam when emitting synchronization signal B of the interrogation package and when emitting synchronization signal D of the coordinate package (Fig. 5-B), the position of the interrogator antenna beam when emitting the information block of both the interrogation and the coordinate package (Fig. 5-C).

[0158] Implementation of the invention

[0159] The proposed method is implemented in a secondary radar system comprising a monopulse interrogator and a set of transponders mounted on mobile objects. To illustrate the method, an example with a set of three transponders is provided. A functional diagram of the secondary radar system is shown in Fig. 2 for one interrogator 1 and one transponder 2.

[0160] The interrogator 1 (Fig. 2) includes an interrogator antenna 4 with high-speed pattern formation and switching, i.e., setting the angular position of the lobes of the pattern, for example, a transmit-receive phased array antenna. The formation and switching of the pattern of the interrogator antenna 4 is carried out under the control of the pattern control module 5 in response to commands from the information processing and technical control module 3.

[0161] The following directional patterns are formed in the interrogator antenna 4:

[0162] - transmitting diagram with one main lobe;

[0163] - two receiving diagrams, each with one main lobe.

[0164] The responder 2 (Fig. 2) uses an on-board transmitting and receiving antenna 18.

[0165] In the information processing and technical control module, 3 interrogators 1 organize a radar survey of the space by performing a series of radar soundings.

[0166] When preparing each radar sounding in the specified module, the following sequence of actions is performed:

[0167] - determine the sounding azimuth;

[0168] - determine the maximum probing range (taking into account the value of the closing angle at the probing azimuth and other conditions of placement and operation of the interrogator);

[0169] - determine the moment of the start of probing and, relative to it, the moment of the cutoff of probing, separated from the moment of the start by the probing time To, which is necessary for the reception of a response message from a conditional responder, located at the maximum probing range from the interrogator (see Fig. 3);

[0170] - determine the azimuths of the installation of the main lobes of both receiving radiation patterns, necessary for the formation of a monopulse pair of intersecting lobes with an axis of symmetry oriented in the direction of the probing azimuth;

[0171] taking into account the shape of the resulting monopulse pair of intersecting petals, a receiving direction-finding characteristic is formed;

[0172] - determine the azimuths P and S of the main lobe of the transmitting radiation pattern, necessary for the formation of a quasi-monopulse pair of intersecting lobes with an axis of symmetry oriented in the direction of the probing azimuth;

[0173] - the values ​​of the azimuths for setting the main lobes of both receiving radiation patterns and the azimuth P are sent to the diagram control module 5, where they are generated and sent to the interrogator antenna 4, and in it, commands are executed for setting the axes of the lobes of the receiving and transmitting radiation patterns in the directions of the specified azimuths;

[0174] - taking into account the shape of the resulting quasi-monopulse pair of intersecting petals, a transmitting direction-finding characteristic is formed;

[0175] - determine the composition of the request information block, include in it, among other things, the general address of the requested objects, the coordinates of the requester, the value of the sounding azimuth, the parameters of the transmitting direction-finding characteristic, issue the listed data to the request information block generation module 8, where the specified block is formed and issued to the coding module 9.

[0176] The cyclogram of the information exchange between the interrogator and three responders in radar probing according to the proposed method is shown in the diagrams of Fig. 3.

[0177] Radar probing begins with the interrogator emitting a interrogation packet (Fig. 3, diagram a).

[0178] The procedure for transmitting a query packet is initiated at the start of probing. It includes the sequential transmission of the query packet elements—sync signals A and B, and the query information block—performed in three steps, observing the time intervals between packet elements established by the query packet structure.

[0179] Step 1. From the information processing and technical control module 3 (Fig. 2) a signal to start the synchronization signal A is sent to the module 6 for encoding the synchronization signal A. Based on this signal, the synchronization signal A is formed and encoded in module 6 and transmitted over the air via the module of the transmitting device 14 and the interrogator antenna 4, the lobe of the diagram of which is pre-set in the direction of azimuth P.

[0180] Step 2. After the emission of the synchronization signal A and before the start of the emission of the synchronization signal B, the value of the azimuth S is sent from the information processing and technical control module 3 to the diagram control module 5, in module 5 a command is generated and sent to the interrogator antenna 4, according to which the axis of the lobe of the transmitting radiation pattern is set in the direction of the azimuth S. Then, from the information processing and technical control module 3, a signal for starting the synchronization signal B is sent to the module 7 for encoding the synchronization signal B. Based on this signal, the synchronization signal B is formed and encoded in module 7 and transmitted over the air via the module of the transmitting device 14 and the antenna of the interrogator 4.

[0181] Step 3. After the transmission of synchronization signal B and before the transmission of the interrogation data packet, the data processing and technical control module 3 sends the sounding azimuth value to the pattern control module 5. In module 5, a command is generated and sent to interrogator antenna 4, which sets the lobe axis of the transmitting radiation pattern in the direction of the sounding azimuth. Next, the data processing and technical control module 3 sends a signal to the interrogation data block encoding module 9 to initiate the specified block. Using this signal, module 9 encodes the interrogation data block and transmits it over the air via transmitter module 14 and interrogator antenna 4.

[0182] The described order of radiation is illustrated in Fig. 4, 5 using the example of interrogator 1 and one of the responders 2.

[0183] Fig. 4 shows the radar sounding azimuth at which the responder 2 enters the lobe of the transmitting diagram of the interrogator antenna 4, as well as the positions of the said lobe in the directions of azimuth P, azimuth S and sounding azimuth.

[0184] As can be seen from Fig. 4, the petals sequentially oriented in the direction of the azimuths P and S form a quasi-monopulse pair of intersecting petals that is symmetrical with respect to the probing azimuth, the presence of which predetermines the possibility of performing in the transponder 2 a quasi-monopulse measurement of the azimuth of the transponder relative to the interrogator.

[0185] Fig. 5-A, 5-B illustrate that the synchronization signals A, B, successively transmitted by the interrogator, reach the responder 2 through different levels of the lobe of the transmitting directional pattern of the antenna of the interrogator 1. The magnitude and sign of the resulting difference in the amplitudes of the synchronization signals at the reception point uniquely determine the deviation of the reception direction from the probing azimuth. Dependency:

[0186]

[0187] where β отв. - azimuth of the respondent,

[0188] β зонд. - sounding azimuth,

[0189] U A - the amplitude of the synchronization signal A at the reception point,

[0190] U B - the amplitude of the synchronization signal B at the reception point,

[0191] represents the request direction-finding characteristic. The request direction-finding characteristic parameters are determined in the processing and technical control module 3 using formula (2) during the preparation of the current sounding, based on the shape and width of the transmitting beam pattern lobe, set in the azimuth directions P and S.

[0192] From Fig. 5-B it can be seen that the orientation of the lobe of the transmitting radiation pattern in the direction of the probing azimuth during the transmission of the interrogating information block will ensure the delivery of the said block to the responder through a lobe level of the transmitting radiation pattern close to the maximum.

[0193] The interrogation packet emitted by the interrogator is sequentially fed to the input of three responders (Fig. 3, diagrams b, c, d). Each responder performs the following sequence of actions to receive the interrogation packet:

[0194] - receive incoming radio signals through the on-board antenna 18 and the on-board receiving device 19 (Fig. 2) and transmit them to the decoding modules 20, 21, 22, 23, 24, 25;

[0195] - in the module 20 for decoding the clock signal A, the clock signal A is decoded, its amplitude is measured and the results are output to the module 21 for decoding the clock signal B, to the azimuth measuring module 26 and to the on-board information processing and interface module 31;

[0196] - in the module 21 for decoding the synchronization signal B, provided that the decoded synchronization signal A is received from the module 20 and taking into account the time interval between the synchronization signals A and B set in the request message, the synchronization signal B is decoded, its amplitude is measured and the results are output to the module for decoding the request information block 22 and to the azimuth measurement module 26;

[0197] - in the module for decoding the request information block 22, provided that a decoded synchronization signal B is received from module 21, taking into account the time interval established in the request message between the synchronization signal B and the request information block, the request information block is decoded and the decoding results are output to the on-board information processing and interface module 31 for further processing and to the azimuth measurement module 26;

[0198] - in the azimuth measurement module 26, the value of the probing azimuth and the parameters of the transmitting direction-finding characteristic are extracted from the request information block, a quasi-pulse estimate of the deviation of the direction of reception from the probing azimuth is performed based on the difference in the amplitudes of the synchronization signals A and B and the parameters of the transmitting direction-finding characteristic, and, knowing the probing azimuth, a quasi-mono-pulse estimate of the azimuth of the responder relative to the interrogator, this estimate is sent to the on-board information processing and interface module 31.

[0199] The procedure for processing the request packet and generating the response packet in the responder is carried out in the on-board information processing and interface module 31 from the moment the decoded synchronization signal A is received. The procedure includes the following actions:

[0200] - extract the data received in the request information block (except for coordinate information) and send it to the on-board equipment interfaced with the transponder;

[0201] - form a response information block, including in it information received from the mated on-board equipment, the individual address of the transponder, the altitude, as well as a quasi-monopulse estimate of the azimuth of the transponder received from the azimuth measurement module 26;

[0202] - with a normalized time shift relative to the moment of receipt of the decoded synchronization signal A, a start signal of the synchronization signal R is generated and sent to the module 28 for encoding the synchronization signal R,

[0203] - with a time shift, relative to the start signal of the synchronization signal R, determined by the structure of the response message, a start signal for this block is generated and sent to the coding module of the response information block 29.

[0204] Then the respondent performs the steps to encode and transmit the response package, including:

[0205] - in the R synchronization signal encoding module 28, the R synchronization signal is encoded according to the trigger signal and sent to the input of the range measurement module 27 and to the input of the on-board transmitting device 30;

[0206] - in the response information block coding module 29, upon the start signal, the specified information block is coded and sent to the input of the on-board transmitting device 30;

[0207] - a response parcel consisting of a synchronization signal R and a response information block is transmitted over the air via an on-board transmitting device 30 and an on-board antenna 18.

[0208] Each response message arriving at the input of interrogator 1 (Fig. 3, diagram a) is received through interrogator antenna 4 and receiving device module 15 (Fig. 2).

[0209] Reception in interrogator antenna 4 is carried out via two channels through two receiving patterns. As noted above, the main lobes of the receiving patterns are preset in azimuth so that, during a given radar scan, they create a monopulse pair of lobes that is symmetrical relative to the scanning azimuth.

[0210] The output of each receiving channel of antenna 4 is connected to its input of the two-channel module of the receiving device 15, the outputs of which are connected to the inputs e, f of the module 16 for decoding the synchronization signal R.

[0211] In module 16, perform the following actions:

[0212] - decodes the synchronization signal R received by module 16 via input e through the first channel of the antenna modules 4 and the receiving device 15, and outputs it via output g to the information processing and technical control module 3;

[0213] - decodes the synchronization signal R received by module 16 via input f through the second channel of the antenna modules 4 and the receiving device 15, and outputs it via output h to the information processing and technical control module 3;

[0214] - I sum up the signals received at inputs e, f, the summed signal is output at output j to the response information block decoding module 17, the synchronization signal R is decoded from the summed signal and output at output i to the information processing and technical control module 3 and to module 17.

[0215] In module 17, the response information block is decoded and sent to the information processing and technical control module 3.

[0216] In module 3, perform the following actions:

[0217] - determine the difference in the amplitudes of the implementations of the synchronization signal R received from module 16 via outputs g, h, taking into account the parameters of the receiving direction-finding characteristic and the known probing azimuth, perform a monopulse estimate of the azimuth of the responder that sent the response message;

[0218] - extract the individual address of the responder and the altitude from the response information block;

[0219] - extract from the response information block the quasi-monopulse azimuth estimate made in the responder, perform joint processing of both azimuth estimates and obtain a refined azimuth estimate;

[0220] - based on the delay time of the decoded synchronization signal R of the response packet relative to the synchronization signal A of the interrogation packet, an estimate of the range of the responder relative to the interrogator is determined;

[0221] - the values ​​of the transponder coordinates - the range estimate, the refined azimuth estimate and the flight altitude together with the individual address of the transponder are issued from the information processing and technical control module 3 to the interacting control point of the ACS as one of the consumers of the coordinate information received in the secondary radar system;

[0222] - transmit from the information processing and technical control module 3 to the interacting control point of the automated control system information received from the on-board equipment interfaced with the responder as part of the response information block.

[0223] The presence in the interrogator of response messages received during this probing determines the need to form and transmit a coordinate message (Fig. 3, diagram a) by performing the following sequence of actions.

[0224] In the information processing and technical management module 3 for each received response package:

[0225] - defines the delay time in the interrogator as the interval from the moment of receiving the synchronization signal R to the cutoff moment (respectively T1, T2 or T3);

[0226] - fill out the respondent form, including the individual address of the respondent and the estimates of the respondent’s coordinates made in the interrogator - range and monopulse estimate of azimuth.

[0227] Further from the information processing and technical management module 3:

[0228] - issue to the module for generating the coordinate information block 12 a general address (if there is only one reply parcel, the individual address of the respondent may be issued instead of the general address) and the forms of each respondent who sent the reply parcel;

[0229] - outputs the azimuth P value to the diagram control module 5.

[0230] In module 12, the formation of a coordinate information block is carried out and the formed block is output to the module for encoding the coordinate information block 13.

[0231] In the diagram control module 5, a command is generated and sent to the interrogator antenna 4, and in it, a command is executed to set the axis of the transmitting diagram lobe in the direction of azimuth P.

[0232] In the information processing and technical control module 3, the following are generated and, starting from the cut-off moment, are sequentially issued (in accordance with the time structure of the coordinate package):

[0233] - in the module 10 for encoding the synchronization signal C - the signal for starting the synchronization signal C, which is then transmitted over the air through the module of the transmitting device 14 and the interrogator antenna 4, the diagram lobe of which is pre-set in the direction of the azimuth P;

[0234] - to the diagram control module 5 - the value of azimuth S, in module 5 they generate and send to the interrogator antenna 4 a command, according to which the axis of the lobe of the transmitting diagram is set in the direction of azimuth S;

[0235] - in the module 11 of encoding the synchronization signal D - the signal for starting the synchronization signal D, which is then transmitted over the air through the module of the transmitting device 14 and the antenna of the interrogator 4, the lobe of the diagram of which is installed in the direction of the azimuth S;

[0236] - to the diagram control module 5 - the value of the sounding azimuth, in module 5 a command is generated and sent to the interrogator antenna 4, according to which the axis of the lobe of the transmitting diagram is set in the direction of the sounding azimuth;

[0237] - in the module for encoding the coordinate information block 13 - the signal for starting this block, the encoded block is transmitted over the air through the module of the transmitting device 14 and the interrogator antenna 4, the diagram lobe of which is installed in the direction of the probing azimuth.

[0238] The described order of radiation is similar to the order of radiation of fragments of the interrogation package and is illustrated in Fig. 5 using the example of interrogator 1 and one of the responders 2.

[0239] After the transmission of a coordinate message in the interrogator, the current probing is completed and the next probing operation is started (Fig. 3, diagram a). The process of further reception of coordinate messages by the responders (Fig. 3, diagrams b, c, d) does not interfere with the execution of the initial phase of the next probing operation in the interrogator.

[0240] The coordinate package transmitted by the interrogator reaches the inputs of three responders as the radio signal propagates (Fig. 3, diagrams b, c, d).

[0241] In each of the defendants, the following sequence of actions is performed:

[0242] - receive incoming radio signals through the on-board antenna 18 and the on-board receiving device 19 (Fig. 2) and transmit them to the decoding modules 20, 21, 22, 23, 24, 25;

[0243] - in the C sync signal decoding module 23, the C sync signal is decoded, its amplitude is measured, and the results are output to the D sync signal decoding module 24, to the azimuth measuring module 26, and to the range measuring module 27;

[0244] - in the module 24 for decoding the synchronization signal D, provided that the decoded synchronization signal C is received from the module 23 and taking into account the time structure of the coordinate message, the synchronization signal D is decoded, its amplitude is measured and the results are output to the module for decoding the coordinate information block 25 and to the azimuth measurement module 26;

[0245] - in the module for decoding the coordinate information block 25, provided that a decoded synchronization signal D is received from module 24 and taking into account the time structure of the coordinate message, the coordinate information block is decoded and the decoding results are output to the on-board information processing and interface module 31 for further processing and to the range measurement module 27;

[0246] - in the azimuth measurement module 26, based on the difference in the amplitudes of the synchronization signals C and D and the previously obtained parameters of the transmitting direction-finding characteristic, a repeated quasi-pulse estimate of the deviation of the direction of reception from the probing azimuth is performed and, having the previously obtained probing azimuth, a repeated quasi-mono-pulse estimate of the azimuth of the responder relative to the interrogator is performed, this estimate is sent to the on-board information processing and interface module 31.

[0247] - in the range measurement module 27, the form of the given responder is extracted from the received decoded coordinate information block, and from it, the delay time in the interrogator, according to the delay time of the decoded synchronization signal C relative to the synchronization signal R for the interrogator;

[0248] In the on-board information processing and coupling module 31, the probing is completed by performing the following actions:

[0249] - extract from the request information block the coordinates of the location of the requestor in the earth's coordinate system;

[0250] - extract from the coordinate information block the range estimate and the monopulse estimate of the azimuth of the responder relative to the interrogator;

[0251] - jointly process the range estimate extracted from the coordinate information block and the range estimate performed in the transponder to form a generalized range estimate;

[0252] - jointly process the monopulse azimuth estimate extracted from the coordinate information block and the quasi-monopulse range estimates made in the responder upon receiving the interrogation and coordinate messages from the interrogator, forming a generalized azimuth estimate;

[0253] - the coordinates of the interrogator's location point, generalized estimates of the range and azimuth of the responder relative to the interrogator are output to the on-board equipment of the carrier interfaced with the responder as a consumer of coordinate information from the secondary radar system.

[0254] The proposed method, in comparison with the prototype method, provides an increase in the accuracy of determining and delivering to consumers coordinate information about moving objects in a secondary radar system.

[0255] First, the method improves the accuracy of direct coordinate estimation in radar sounding by performing measurements not only in the interrogator, as in the prototype method, but also in the transponder, and by jointly processing the obtained results. Thus, azimuth estimation in the interrogator is achieved by jointly processing two independent measurements—one in the interrogator and one in the transponder; range estimation in the transponder is based on the results of two independent measurements—one in the interrogator and one in the transponder; and azimuth estimation in the transponder is based on the results of three independent measurements, one in the interrogator and two in the transponder.

[0256] Assuming the simplest version of joint processing - equilibrium averaging of measurement results under the assumption of identical variances (root mean square values) of the distribution of errors of each of the results in accordance with the formula for the variance of the sum of independent random variables (see, for example, [6], p. 51) we obtain:

[0257] - decrease in the interrogator's azimuth estimation error of the responder relative to the interrogator by 2 1 / 2 =1.41 times;

[0258] - reduction in the responder's azimuth estimation error relative to the interrogator by 3 1 / 2 =1.73 times;

[0259] - reduction in the responder's error in estimating the range of the responder relative to the interrogator by 2 1 / 2 =1.41 times.

[0260] Secondly, the method eliminates errors associated with the prototype method, which stem from the delay between the moment coordinates are measured in the interrogator and the moment the coordinate information is delivered to the onboard equipment of the mobile object. Such errors are eliminated because, unlike the prototype method, the process of determining coordinates and delivering coordinate information to both users is fully accomplished within a single radar acquisition.

[0261] Literature

[0262] 1. Annex 10 to the Convention on International Civil Aviation, Volume IV "Surveillance and Collision Avoidance Systems", paragraphs 2.1, 3.1.1. ICAO, ed. 5, 2014.

[0263] 2. Annex 10 to the Convention on International Civil Aviation, Volume IV "Surveillance and Collision Avoidance Systems", paragraphs 2.1, 3.1.2. ICAO, ed. 5, 2014.

[0264] 3. ICAO Doc 9924 "Aeronautical Surveillance Manual", Ch. 5.3, Supplement E, Edition 3, 2020.

[0265] 4. ICAO Doc 9684 "Manual of Secondary Surveillance Radar Systems", Ch. 5, Ed. 3, 2004.

[0266] 5. Theoretical Foundations of Radar. Edited by Ya.D. Shirman. Soviet Radio Publishing House, Moscow, 1970.

[0267] 6. B.R. Levin. Theoretical Foundations of Statistical Radio Engineering. Radio and Communications Publishing House, Moscow, 1989.

Claims

A method for determining and delivering coordinate information to consumers in a secondary radar system, which consists of: The secondary radar system includes a monopulse interrogator and a set of responders placed on moving objects; each defendant is assigned an individual address; to address multiple defendants, a general address is used; for each defendant, an individual and general address is entered; The interrogator uses a directional antenna with single-lobe radiation patterns - two receiving lobes, the lobes of which intersect and together form a monopulse pair, and one transmitting lobe; taking into account the shape of the monopulse pair in the interrogator, a receiving direction-finding characteristic is formed; the responder uses an omnidirectional transmitting and receiving antenna; in the interrogator, a periodic review of the space is organized by performing radar soundings using request and response messages; the structure of the request package includes the synchronization signal A and the request information block; the basic information composition includes the individual address of the requested respondent or the general address; the structure of the response package includes a synchronization signal R and a response information block; the basic information composition includes the individual address of the responder and the flight altitude of the mobile object carrying the responder; in the interrogator for each radar sounding, the sounding azimuth and the maximum sounding range are determined; on radar sounding: - a request message is generated and transmitted in the requester, - each responder that has received the interrogation message sends the data received in the interrogation information block to the interfaced on-board equipment of the mobile object, forms and transmits a response message, - in the requester upon receipt of the received reply parcel: extract the individual address of the defendant and the height from the parcel, based on the delay time of the synchronization signal R of the response message relative to the synchronization signal A of the request message, the range of the responder is estimated, based on the ratio of the amplitudes of the synchronization signal R received through each of the petals of the monopulse pair, the parameters of the receiving direction-finding characteristic and the value of the probing azimuth, a monopulse estimate of the azimuth of the transponder is performed, send the individual address of the responder, the altitude and the range estimate to the interrogator's output for transmission to the control center interacting with the interrogator; in the interrogator, radar sounding is completed and the next sounding is carried out, characterized in that: the interrogator uses an antenna with a fast-acting setting of the azimuth position of the directional pattern lobes; in addition to the sync signal A, the structure of the request message includes the sync signal B; to carry out radar soundings, in addition to the request and response packets, they also use a coordinate packet as part of the synchronization signal C, the synchronization signal D and the coordinate information block; a general or individual address is included in the basic information composition; a monopulse pair of intersecting lobes and a receiving direction-finding characteristic are formed in the interrogator for each radar sounding, and the axis of symmetry of the monopulse pair is oriented in the direction of the sounding azimuth; in the interrogator for each radar sounding, in addition: - determine the azimuths P and S, with the sequential installation in the direction of which the lobe of the transmitting directional pattern forms a quasi-monopulse pair of intersecting lobes, symmetrical with respect to the probing azimuth, - taking into account the shape of the quasi-monopulse pair, a transmitting direction-finding characteristic is formed, - the request information block of the request message includes the coordinates of the requester, the sounding azimuth, the parameters of the transmitting direction-finding characteristic, - the moment of probing cutoff is determined as the moment of completion of the reception of the conditional response message transmitted from the maximum probing range; on radar sounding: - in the interrogator, when transmitting the interrogation message, the axis of the lobe of the transmitting directional diagram is set in the direction of azimuth P and the synchronization signal A is emitted, set in the direction of azimuth S and the synchronization signal B is emitted, set in the direction of the probing azimuth and the interrogation information block is emitted, - in each responder that has received the interrogation message, based on the ratio of the amplitudes of the synchronization signals A and B, the parameters of the transmitting direction-finding characteristic and the value of the probing azimuth, a quasi-monopulse estimate of the azimuth of the responder relative to the interrogator is produced, this estimate is included in the response information block, - in the requester, upon receipt of each response parcel, additionally: carry out joint processing of the estimate of the azimuth of the responder, performed in the interrogator, and the estimate received from the responder, form a refined estimate of the azimuth of the responder and include it in the data sent to the output of the interrogator, determine the delay time in the interrogator from the moment of receiving the synchronization signal R of the response packet to the moment of probing cutoff, fill out the defendant form, which includes the defendant's individual address, the delay time in the interrogator, the azimuth estimate and the range estimate of the defendant, completed in the interrogator; - in the interrogator, if there is at least one response message received during probing, a coordinate message is formed and transmitted, for which: the forms of the defendants are included in the coordinate information block, the transmission of the coordinate package begins at the moment of the sounding cutoff; during transmission, the lobe of the transmitting directional pattern is set in the direction of azimuth P and the synchronization signal C is emitted, set in the direction of azimuth S and the synchronization signal D is emitted, set in the direction of the sounding azimuth and the coordinate information block is emitted; In the interrogator, completion of radar sounding and transition to the next sounding is carried out by: - in the absence of a coordinate package - at the moment of sounding cutoff, - if there is a coordinate parcel - at the moment of completion of its transmission; in each respondent who received the coordinate message: - extract from the coordinate information block the form with the individual address of the given defendant, - based on the delay time of the synchronization signal C of the coordinate package relative to the synchronization signal R of the response package, excluding the delay time in the interrogator, the range to the interrogator is estimated, - based on the ratio of the amplitudes of the synchronization signal C and the synchronization signal D, a quasi-monopulse estimate of the azimuth of the responder relative to the interrogator is performed again, - carry out joint processing of range estimates received from the interrogator and performed in the responder, azimuth estimates received from the interrogator and performed in the responder, and form a generalized range and azimuth estimate, - send a generalized estimate of the range and azimuth together with the coordinates of the interrogator to the mating on-board equipment of the moving object.

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