Prior art is mainly that the wide area that air-sea moving-target is carried out using ground mechanical scanning radar or phased-array radar is visitedSurvey.In order to realize a wide range of fast search, the narrow beam that radar is sent can not be resident the long period in a certain position, and air-sea movesAlso there is range walk, doppler ambiguity phenomenon in the echo-signal of target, this just has a strong impact on the energy accumulation between target pulse,Cause detection performance to decline, or even the remote or less moving targets of moving-target Radar Cross Section RCS can not be detected.
It is divided into following two for ground mechanical scanning radar or the moving-target test problems of phased-array radar, research methodClass：
(1) tracking (TBD) before detecting：TBD classes method is believed the echo after pulse pressure using the method for non-inherent accumulationNumber handled, but in the case where signal to noise ratio is relatively low, this method accumulation efficiency is not high.
(2) tracking (DBT) after detecting：DBT classes method was mainly studied in long coherent integration time, the distance of moving-targetWalk about and compensate and doppler spread compensation.Existing range walk compensation method main subpackage network shift compensation method, frequency division sometimesEnvelope shift compensation method, envelope interpolation displacement method, coherent Radon converter techniques, Radon-Fourier converter techniques, Keystone becomeChange method etc..Existing doppler spread compensation method mainly has maximum likelihood function method (ML), solution line to adjust method or Chirp-Fourier conversion, Radon-Wigner conversion, Wigner-Hough conversion, Radon-ambiguity conversion, chirplet becomeChange, Fourier Transform of Fractional Order etc..
By patent retrieval, utility model patent 1, patent of invention 4, a kind of passive radar bilateral of difference are retrieved altogetherRoad receiver radio frequency cancellation system (CN 201420048872), a kind of passive radar two-channel receiver radio frequency offset method (CN20141003641) phase-coherent accumulation detection method (CN that is, a kind of while correcting single order and second order range migration201410654337), based on Keystone and weighting rotation FFT object detection method (CN 201510150340) and faintSignal receiving front-end and method of reseptance (CN 201610557183).
Preceding two patents focus on description passive radar two-channel receiver radio frequency cancellation system and method, are offseted by radio frequencySuppress the direct-path signal in external sort algorithm signal, so as to extract the reflected signal of weak target, last patent focuses onHigh-sensitivity radio frequency front end circuit design method is described, it is not high with this patent degree of correlation.The present invention and remaining two patentResearch object is different, and above-mentioned patent studies moving target detection method mainly for ground mechanical scanning radar or phased-array radar,And the present invention proposes a kind of space-based air-sea moving-target wide area detection system, its working system and traditional ground mechanical scanning radarOr phased-array radar is entirely different, there is also notable difference for corresponding moving target detection method.
The content of the invention
It is an object of the invention to provide a kind of space-based air-sea moving-target wide area detection system, by using Digital Array RadarAntenna, bistatic radar configuration and general detect a mine realize the wide area detection of air-sea moving-target up to working system, can overcome traditionallyCause detection property with doppler ambiguity because wave beam residence time is short, target range is walked about when base radar wide area detects air-sea moving-targetThe problem of even failing can be declined.
A kind of space-based air-sea moving-target wide area detection system provided by the invention, it is included：
Launch satellite, it is provided with radiates microwave signal to ground-plane antenna by broad beam, covers whole search coverage；
Satellite is received, it is provided with the antenna sidelobe work that the wave antenna that gone directly to terrace receives the microwave signal by broad beamFor direct-path signal, it is additionally provided with and the antenna main lobe by microwave signal is received through detection by narrow beam to ground digital array antennaRegion inland sea null object reflects formed echo-signal.
Preferably, the digital array antenna module that M × N number of process signal is included to ground digital array antenna, instituteDigital array antenna module is stated each via the first RF receiving and transmission module being internally integrated, the first intermediate frequency amplification module and the first letterNumber acquisition module, it is connected with igh-speed wire-rod production line unit fiber optic communication on the star of the reception satellite.
Preferably, first RF receiving and transmission module carries out amplitude limit, wideband filtered, LNA and Frequency mixing processing successively；InstituteState the first intermediate frequency amplification module and be filtered amplification, numerical control attenuation and filter amplifying processing successively；The first signal acquisition mouldBlock carries out high speed analog-to-digital conversion, numerical control down coversion, filtering extraction and electro-optic conversion processing successively.
Preferably, by it is described to ground digital array antenna receive echo-signal, successively through the first RF receiving and transmission module,After first intermediate frequency amplification module and the processing of the first signal acquisition module, high speed signal on the star is transferred into by fiber optic communicationAfter carrying out opto-electronic conversion in the photoelectric conversion module of processing unit, then it is transferred on star at the FPGA of igh-speed wire-rod production line unitCross-correlation, correlative accumulation, CFAR detection and target information extraction process are carried out successively in reason module group.
Preferably, the wave antenna that gone directly to terrace by being internally integrated the second RF receiving and transmission module, the second intermediate frequency is putIgh-speed wire-rod production line unit communication connects on the direct wave component of big module and secondary signal acquisition module, with the star of reception satelliteConnect.
Preferably, second RF receiving and transmission module carries out amplitude limit, wideband filtered, LNA and Frequency mixing processing successively；InstituteState the second filter and amplification module and be filtered amplification, numerical control attenuation and filter amplifying processing successively；The secondary signal gathers mouldBlock carries out high speed analog-to-digital conversion, numerical control down coversion, filtering extraction and electro-optic conversion processing successively.
Preferably, by the direct-path signal of the wave antenna reception of being gone directly to terrace, successively through the second radio-frequency receiving-transmittingAfter module, the second intermediate frequency amplification module and the processing of secondary signal acquisition module, igh-speed wire-rod production line list on the star is transferred intoAfter carrying out opto-electronic conversion in the photoelectric conversion module of member, the FPGA processing module groups of igh-speed wire-rod production line unit on star are transferred intoIn carry out cross-correlation, correlative accumulation, CFAR detection and target information extraction process successively.
Compared with prior art, beneficial effects of the present invention are：(1) present invention uses the double star configuration of bistatic, withThe ground monostatic radar of prior art is compared, and bistatic angle of scattering can increase the Target scatter section area RCS of air-sea moving-target, carryHigh target echo energy and detection probability；(2) the general detecting a mine that the present invention sends out receipts narrow using width reaches working system, with prior artNarrow beam machine is swept to be compared with phase-scan radar, instantaneously covers whole investigative range, and without wave beam full-field scanning process, air-sea moves meshMark in the range of radar beam, is easy to backward energy correlative accumulation for a long time, improves target detection probability；(3) present invention adoptsWith Digital Array Radar antenna, compared with prior art and poor triple channel radar, digital beam froming skill on the one hand can be utilizedArt forms multibeam simultaneously, instantaneously covers investigative range, and the echo data of another aspect M × N number of passage can use arraySignal processing method realizes clutter recognition and moving-target detection.
Embodiment
The invention provides a kind of space-based air-sea moving-target wide area detection system, to become apparent the present invention, belowWith reference to accompanying drawing, the present invention will be further described with embodiment.
With reference to shown in Fig. 2, Fig. 4 and Fig. 5, the present invention using width send out narrow receive and bistatic double star configuration, its include oneTransmitting satellite 1 and one reception satellite 2.
Transmitting satellite 1 launches microwave signal using a pair to ground broad beam antenna, prolonged exposure, covers whole detectionRegion.The broad beam antenna transmitting antenna secondary lobe and antenna main lobe, antenna sidelobe is as direct-path signal, antenna main lobe signal warpSearch coverage inland sea null object has reflected to form echo-signal.
Satellite 2 is received to include to igh-speed wire-rod production line unit on ground digital array antenna 3, direct wave component and star；DirectlyThe wave antenna 4 that gone directly to terrace is included up to ripple component, so receiving satellite 2 has used two antennas：One to terrace direct wave dayLine 4 receives the direct-path signal of transmitting satellite 1 using broad beam, and another is connect to ground digital array antenna 3 using narrow beamReceive the echo-signal of search coverage inland sea null object.Receive satellite 2 uses Digital Array Radar to ground digital array antenna 3Antenna, when receiving the echo-signal of air-sea target, while form multibeam and instantaneously cover whole investigative range, in high velocity starThe a wide range of fast search of target is realized on carrying platform.
Direct wave component also includes Receiver Module, intermediate frequency amplification module and signal acquisition module；Receiver ModuleProvided with frequency mixing module, intermediate frequency amplification module is provided with filter and amplification module, and signal acquisition module is provided with analog-to-digital conversion (A/D, analogTo digital converter, i.e. electro-optic conversion are by analog signal digital) module.
Ground digital array antenna 3 is made up of M × N number of R components, each R component internals are integrated with radio frequency receivingBlock, intermediate frequency amplification module and signal acquisition module, and its Receiver Module is provided with frequency mixing module, intermediate frequency amplification module is provided with filterRipple amplification module, signal acquisition module are provided with analog-to-digital conversion module.
Igh-speed wire-rod production line unit includes photoelectric conversion module and field programmable gate array (FPGA, Field- on starProgrammable Gate Array) processing module group.
The wave antenna 4 that gone directly to terrace receives direct-path signal by broad beam, then is received by the wave antenna 4 that gone directly to terraceLaunch the direct-path signal of satellite 1, direct-path signal passes through Receiver Module, intermediate frequency amplification module and signal acquisition successively againResume module, then igh-speed wire-rod production line unit on star is transferred into, it is transferred into FPGA processing module groups after carrying out opto-electronic conversionIn be sequentially completed cross-correlation, correlative accumulation, CFAR detection and target information extraction.It is only so as to form a direct wave information flowVertical passage, completes the reception processing of direct-path signal.
Wherein, the Receiver Module can be sequentially completed amplitude limit, wideband filtered, LNA and mixing；The intermediate frequency amplifies mouldBlock can be sequentially completed filter and amplification, numerical control attenuation and filter and amplification；The signal acquisition module can be sequentially completed high speed analog-to-digital conversion(high-speed a/d), numerical control down coversion, filtering extraction and electro-optic conversion.
To the R components of ground digital array antenna 3 by narrow beam come the echo of receives echo-signal, then M × N number of passageSignal is successively by Receiver Module, intermediate frequency amplification module and signal acquisition module processing, then be transferred on star and believe at a high speedNumber processing unit, be transferred into FPGA processing module groups after opto-electronic conversion and is sequentially completed cross-correlation, correlative accumulation, permanent emptyAlert detection and target information extraction.
Wherein, the Receiver Module can be sequentially completed amplitude limit, wideband filtered, LNA and mixing；The intermediate frequency amplifies mouldBlock can be sequentially completed filter and amplification, numerical control attenuation and filter and amplification；The signal acquisition module can be sequentially completed high speed analog-to-digital conversion(high-speed a/d), numerical control down coversion, filtering extraction and electro-optic conversion.
The mark echo-signal on M × N roads can be received to M × N number of R components of ground digital array antenna 3, so as to formM × N bar echo information streams autonomous channel, completes the reception processing of echo-signal.
So the reception satellite 2 of the present invention is completed to launch the radiation signal of satellite 1 using M × N+1 bars autonomous channel altogetherReception processing.
The present invention is that a kind of width using double star framework is sent out narrow to receive and the general detecting a mine of bistatic reaches working system, and this is in skyBetween on ensure that direct-path signal and the Signal segregation degree of echo-signal, be advantageous to purification and the echo-signal of direct-path signalDirect wave suppresses.Because echo-signal may be from ground static target, ground moving target and aerial moving-target, so to throughRipple signal and echo-signal carry out cross correlation algorithm processing and filtering algorithm processing, can be achieved to move mesh to aerial moving-target and groundTarget detects and tracking.
Shown in radar effect equation such as formula (1)：
Wherein, S is antenna area, PtIt is transmitting satellite radiated power, σ is Target scatter section area, and τ is processing time,KT is thermal noise density, and F is noise coefficient, LαIt is system loss, λ is operation wavelength, RmaxIt is reception signal stroke, with low railThe orbit altitude R of satelliteLOSAs transmission signal stroke.
Shown in radar beam angle equation such as formula (2)：
Wherein, θ is transmitted wave beam angle,It is to receive field angle.
Traditional phased-array radar working system as shown in Figure 3 a, transmitting satellite 1 are defended with receiving satellite 2 using low railStar, and keep geo-stationary, launch the launching beam of satellite 1, receive satellite 2 and receive wave beam, H be receive satellite or transmitting satellite withVertical range between ground.Wherein, the wave beam of transmitting and the wave beam received point to a less region L on ground simultaneously.Mode is swept using two-dimensional phase, synchronous change launching beam is pointed to realize that whole search coverage L' search is covered with reception wave beamLid.
Parameters are as follows：Pt=100W, σ=1m2, τ=0.1s, kT=-204dB, F=5dB, Lα=8dB, λ=0.02m, Rmax=700km, RLOS=500km；Then obtain launching satellite and receive the antenna area S about 9m of satellite2。
Calculated according to above-mentioned parameter, formula (1) and formula (2), obtain the transmitted wave of traditional phased-array radar work systemBeam angle θ and reception field angleOnly 0.4 ° or so.So in the high speed motions of low orbit satellite, synchronous change is launchedSatellite 1 and the radar beam for receiving satellite 2, and its moment is remained pointing to same smaller area L, difficulty is too big.
The width of the present invention send out narrow to receive and the general detecting a mine of bistatic reach working system, launches satellite 1 and is also adopted with reception satellite 2With low orbit satellite, and geo-stationary is kept, as shown in Figure 3 b, and calculated according to above-mentioned formula (1) and formula (2), it is eachParameter value is the same as above-mentioned traditional phased-array radar working system.
Transmitting satellite 1 radiates broad beam signal using broad beam antenna (Cassegrain antenna), then radar wave beam angle θ '=15 °, instantaneously cover whole search coverage L'.Satellite 2 is received using to ground digital array antenna, using digital beam simultaneouslyProduceIndividual multibeam, andInstantaneously cover whole search coverage L'.This efficiently solves traditional phaseThe launching beam and receive beam Synchronization illumination issues that control battle array radar faces, so the present invention is compared with the prior art, its complexityIt is low and be easily achieved.
Fig. 1 a and Fig. 1 d are respectively aerial target and sea-surface target schematic diagram, and Fig. 1 b and Fig. 1 c are air contact respectively90 ° and the 60 ° of biradical RCS of incidence (moving-target RCS) specificity analysis schematic diagrames, Fig. 1 e and Fig. 1 f are detection sea respectively90 ° and 60 ° biradical RCS specificity analysises schematic diagrames of incidence of Area Objects.
For aerial target, single base RCS of Typical Aerial Targets is in 10dB or so, and imitating shown in Fig. 1 b and Fig. 1 cTrue result shows that under conditions of incidence angle is 60 ° and 90 °, biradical RCS shakes reduction with the increase of angle of reflection, andIn 10dB~40dB.
For sea-surface target, single base RCS of typical sea-surface target is in 30dB or so, and imitating shown in Fig. 1 e and Fig. 1 fTrue result shows that under conditions of incidence angle is 60 ° and 90 °, biradical RCS shakes reduction with the increase of angle of reflection, andIn 30dB~60dB.
From above-mentioned simulation analysis result, the biradical RCS ratios list base RCS of aerial target and sea-surface target can be improved about30dB, i.e., the biradical detection be advantageous to targets such as naval vessel, aircrafts.
In summary, the present invention uses space-borne bistatic radar configuration, and collocation field and the earth for breaking away from ground-based radar are bentRate is limited to, and realizes that global range air-sea target wide area detects, and using bistatic angle of scattering increase air-sea moving-target RCS, is improvedTarget echo energy and detection probability.
The reception satellite of the present invention uses wave antenna broad beam of being gone directly to terrace to receive the radiation signal secondary lobe for launching satellite,Air-sea target echo signal is received using to ground digital array antenna narrow beam, from the signal that spatially ensure that two antennasIsolation, the direct-path signal for being advantageous to direct wave purification and echo-signal suppress.
The transmitting satellite of the present invention, persistently to eradiation HIGH-POWERED MICROWAVES signal, covers whole detecting area using broad beamDomain, receive the echo-signal that satellite receives search coverage inland sea null object using narrow beam.One side bistatic can reduceSystem complexity, is easy to Project Realization；On the other hand to ground digital array antenna simultaneously produce multibeam instantaneously cover it is wholeIndividual investigative range, without wave beam full-field scanning process, air-sea moving-target in the range of radar beam, is easy to echo for a long timeEnergy correlative accumulation, improve target detection probability.
Although present disclosure is discussed in detail by above preferred embodiment, but it should be appreciated that above-mentionedDescription is not considered as limitation of the present invention.After those skilled in the art have read the above, for the present invention'sA variety of modifications and substitutions all will be apparent.Therefore, protection scope of the present invention should be limited to the appended claims.