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:2001-03-20;:2001-05-20:(9931.3.3BG0106)::1000-6893(2001)S0-0S16-10,,(,100081)DIGITALSIGNALPROCESSINGOFSTEPPEDFREOUENCYRADARLONGTeng,HANYue-giu,MAOEr-ke(Dept.ofElectronicEngineering,BeijingInstituteofTechnology,Beijing100081,China):,~~Chirp~,,O:;;;:V243:AAbstract:Steppedfreguencyradarisaveryimportanttypeofthehighrangeresolutionradarsystem.Thekeyproblemsofthesteppedfreguencyradararediscussedinthispaper,includingtheWaveformdesign,thealgorithmsoftargetextraction,theprocessingofModulatedFreguencySteppedRadarSignal,andthecom-patibilitybetWeensteppedfreguencyradarandconicalscanradar.Ineachsituation,theDopplereffectsareanalyzed.Andsomeprocessingschemesaregiven.Keywords:radar;highrangeresolution;steppedfreguency;signalprocessing[1］,[2］O,IFFT[2］O,O,[3］,[2,4］O:d,;i,,[5］O,,1m,[5］O,,[6］~[2］~[2］~[＠］O,,O,O,[8］,[9］,[10］,[11］,[12］(Chirp),[13,14］,[15,16］O,,,[1＠—2＠］O,O,,,,,O2220016ACTAAERONAUTICAETASTRONAUTICASINICAVol.22Sup.————————————————————————————————————————————————————————————————June200111.1:Tr,T,fO,af,N,fS,TS=1/fS,CG5(t)=ZN-1z=Orectt-zTr-T/Z()T-exp[-jZT(fO-zaf)t](1):rect(t/T)=1,-T/ZtT/ZO,{;(t)=ZN-1z=Orectt-zTr-Tr/ZT()r-exp[-jZT(fO-zaf)t](Z)Ry(t)=ZN-1z=Orectt-zTr-TZ-ZRCLWJT-exp-jZT(fO-zaf)t-ZR()[]C(3)y(t)=ZN-1z=Orectt-zTr-TZ-ZRCLWJT-exp-jZT(fO-zaf)ZR[]C=ZN-1z=Orectt-zTr-TZ-ZRCLWJT-exp-jZTfOZR[]Cexp-jZTzafZR[]C(4),(4)1,ZZR/C,G,,[]y(z)=exp-jZTzl/N(5):l=Round(ZRNaf/C),z=O,1,Z...N-1,RoundG(5)IFFT,ZR/CGy(k)=Sin[T(-l-k)]SinT(-l-k)[]N;k=O,1,Z,.,N-1(),k=l,kRG1.,6,(t),(t)()G,:6(),6(),IFFT,(t),()G,,,GB=NafN,,G,,N,,G[11]GZ.1,T;af;N;TSTrGRu~B=Naf~E,,[18],:(1)IFFT1IE,afC/(ZE)G(Z)B~afN,N=B/afG(3)RTr,Tr=ZR/CG(4),IFFT1I1T,T1/af,TafG(5)TTS,TSTG(),T-TSZ/af,,,T,af,TSG,,IFFT1I,715:2TS{z0IFFT~~0;'0z.z2:D;@001)IFFT0s)IFFTYk)=ZN1z=Oexp[j2mzl/N]exp[j2mzk/N]7)k=l+PNP=)0IFFTkPN+k)AT=PTI+kATk=O12...N1AT0IFFT0HIFFTkP0HIFFTHTS{THHTS+TzH=O12-8)HkPHIFFTk007)HIFFTkIFFTk0HIFFT0OHTS+Tz0HTSHTS+TzTz101Fig.1Targetextractionbycyclicextrapolation20'~'~'03:00IFFT002)IFFT000TzTI081522*2O2Fig.2TargetextractioHbycyclicextrapolatioH*nIFFT*n1S-(1z-1I)/A11nn1S-1T-(1T-rI)/A1n=0*1*2*(9)O*O::N=128*Af=8MHZ*fS=30MHZ*A1=0.14648m*3*R1=60m*R2=65m*R3=66m*S/N=10dB**z=100HS*fS=30MHZ20IFFT3O3(a)IFFT*9*11;(b)(c);(d)Fig.3SimulatioHoftargetextractioHalgorithm3(a)91*1021\2*1122\3*IFFTO3(b)***3;3(c)*ltu3(a);3(d)*O91S:z.s1,,[11],,V,expZnfOZV/C:TK1OexpZTafZV/C:ZTK11,IFFT,V;IFFT,V,,,,[11],,1m/S,1OOm/SZ,[17],~~;~~,,[1S],,[19]~,,FFT,IFFT[ZO]B,~~IFFT,,IFFT,,,,,,,[Z1~Z4],,,,9O[Z5],[Z6]PRT,[Z7],,BD,,IFFT,,,,;,1m/S,,1OOm/S,,IDFT,@,,,,,,,[ZS],[19,ZO][19],,;,,,,,OZ%ZZPRT9O[2O]9;999O@9999-O[21\2]9O99O[21922][29]96dBO[23924]O99O99(12)999O[23924]99O9WVD99O@9O9;9IFFT9O9O@99O2.4Chirp99N9af;z99O9(Chirp)9[12]';zBN9OBNz9OChirpO(1)zx(t)=1~NEN-1z=Ou(t-zTr)exp[j2tzaf]-exp[j2tfOt]=1~NzEN-1z=Orectt-zTr()z-exp[jtK(t-zTr)2]exp[j2tzaf]-exp[j2tfOt](12),u(t)=1~zrectt()zejtK(t-zTr)2Chirp;K=af/zONafOx(t)=EN-1z=OAzrectt-zTr-2(R-Vt)/c()z-exp{jtK[t-zTr-2(R-Vt)/c)]2}-exp[-j2tzaf2(R-Vt)/c]-exp[-j2tfO2(R-Vt)/c](13)[12]92,Chirp;IDFTOO(6)9NOIFFT99ChirpOV#O9O(2)PRT9O[12]9NPRT92VNTr/C1/(2af)Chirp~~IFFT12S,OChirp,O,IFFTON,IFFTO(3),,4O4Fig.4BlockdiagramofthedigitalSigHalproceSSorforFMStep-fregueHcyradarecho~,OTMS3Z0C6XDSPO(VLIW):8,8;Z00M~Z,5HS,1600MIPSOO2.5,O,,,O,O(1)7,;fa;O,O;A;x;E;00;Ax,Ay,5O,,M=1/(faNTr)O0,mz,x(z)={1+7EcoS[Ztfa(mNTr+zTr+ZR/C)+00]}eXp[-jZT(f0+iaf)ZR/C]m=0,1,Z,~M-1;z=0,1,Z,~N-1(14),OO7,,O~~O5Fig.5DemoHStratioHfothepriHcipleofcoHicalScaH,NTrO,,OZfa1/NTrO,,OO,IFFTO(14)IFFTY(k)=N+7ESiH(tl/M)SiH(tl/(MN))coSZtlMm+hNZTr()af[+00+tlMN-1]N,k=h0,k=!(15):k=0,1,Z~N-1;m=0,1,Z~M-1;l=ZZSZZMfaNTr;h=2RNAf/CO,IFFT,E,60O,,MO'',M,O,MDFT,fa,A,g,E,60EO27Asin(Tl/(MN))/sin(Tl/M)60=Z2TlhMN2TrAfTlMN1N(16)E,60,MO(2),6OADSP-21060DSP,ODSP,40MHZ,4M-bitrAM,,6ink,OO7,7(a)4:70m,73m,78m,85m;7(b):0.293,4:70.02m,72.95m,77.93m,84.96mO7,,O6Fig.6Blockdiagramofthedigitalsignalprocessorforconicalscanstep-freguencyradarecho7()(a);(b)();(c)E;(d)60Fig.7ProcessingresultfortheSimulatedradarecho32S:3,;,,;,,,,N,;Chirp,IFFT;,DFT,,,,,:;~;,,~,[1]SkolnikMI.IntroductiontoradarSyStem[M].NeWYork:McgraW-~illBookCo,1980.[2]WehnerDR.~ighreSolutionradar[M].BoSton:Artech~ouSe,1995.[3]RuttenburgK,GhanZitL.~ighrangereSolutionbymeanSofpulSe-pulSefreguencyShifting[M].EASCON,1968.47[4]EinSteinT~.GenerationofhighreSolutionradarrangeprofileSandrangeautocorrelationfunctionSuSingSteppedfreguencypulSetrainS[R].ProjectReportTT-54,MITLincolnLaboratory,1984.[5]FarguharSonG,etal.A50-800M~ZSteppedfreguencycontinuouSWavegroundpenetratingradar[A].Proceed-ingSofthe1998SouthAfricanSympoSiumonCommunica-tionandSignalProceSSing-COMSIG/98[C].RondeboSch,SouthAfrica,1998.455-460.[6]ClarkME,etal.~ighrangereSolutiontechnigueSforbal-liSticmiSSiletargetS[A].IEEColloguiumon~ighReSolu-tionRadarandSonar[C].London,UK,1999.[7]KajiWaraA,etal.Stepped-FMpulSeradarforvehicularcolliSionavoidance[J].TranSactionSoftheInStituteofElectronicS,InformationandCommunicationEngineerSB-II,1998,J81B-II(3):234-239.[8].[J].,1989,11(4):31-3