GPS软件接收机的信号捕获和跟踪

MICROPROCESSORSGPS*鲍雍荣,李振波,陈佳品(上海交通大学微纳科学技术研究院微系统与集成技术研究所,上海200030):由于GPS软件接收机的高度灵活性,其应用也越来越广泛这里我们使用Zarlink的GP2015和GP4020硬件电路接收卫星信号,将其降至中频IF,将模拟信号采样转为数字信号之后将数字信号传送给PC机,在PC机上用Matlab对接收到的信号进行捕获和跟踪,之后将得到的GPS导航信号传给后面的处理模块,最终得到位置坐标:软件接收机;C/A码;多普勒频移;循环相关;快速傅立叶变换;:TN967.1:A:1002-2279(2008)01-0121-03AcquisitionandTrackingforGPSSoftwareReceiverBAOYong-rong,LIZhen-bo,CHENJia-pin(MicroSystemandIntegratedTechnologyResearchDepartment,InstituteofMicroandNanoscienceandtechnology,ShanghaiJiaotongUniversity,Shanghai200030,China)Abstract:GPSsoftwarereceiverisbecomingmoreandmorepopularbecauseofitsflexibility.Here-byweareusinganexternalhardwarecircuitboard,whichconsistsofZarlinkGP2015andGP4020,toreceivetheGPSsigna,lconvertittoIFandsampleitintodigitalsigna.lThenaftertransferringthesignaltothePC,dotheacquisitionandrackingusingMatlab.Afterthatwecangetthenavigationinformationandwepasstheinformationtothefollowingprocessingmoduleandgettheuserpositionintheend.Keywords:GPSSoftwareReceiver;C/ACode;Doppler;CircularCorrelation;FFT1GPSGPS,GPS(ASIC),,,,,,,GPS,,,,[1]ZarlinkGP2015,GP4020MatlabPC,GPS,1GP2015GPS,(IF)4309KHz,GP4020A/D,40/7MHzFPGAPC,Matlab,1GPS2GPSC/A[5],2C/A,Nx(n)(GPS)(DFT):X(k)=N-1n=0x(n)e-j2kn/N(1)Nx(n)y(n)(C/A):120082No.1Feb.,2008*:(10477013,60475037):(1981-),,,,::2006-10-10z(n)=N-1m=0x(m)y(n+m)(2)(1)(2)xy(DFT):Z(k)=N-1n=0N-1m=0x(m)y(n+m)e-j2kn/N=N-1m=0x(m)e-j2km/NN-1n=0y(n+m)e-j2k(n+m)/N=X*(k)Y(k)(3)*2C/A(3),xy(DFT)XY,Z,Z(n)=F-1(Z(k))(4)z(n)(),Z(i)max,,10KHz,10KHz[2],500Hz,41(4299KHz,4299.5KHz,4300KHz,4309KHz,4318KHz,4318.5KHz,4319KHz)C/A(500Hz)(),,32540/7MHz[3],1ms[2]GPS,5714,C/A3GPS[5]Early-LateC/A(PLL),GPS,GPS,IQPRN(E)(P)(L)(1/2),,(5)PRN,,C/AD=(I2E+Q2E)-(I2L+Q2L)(I2E+Q2E)+(I2L+Q2L)(5),C/A,,:Ik=Dk(n)cos(IFn)cos(IFn+)=12Dk(n)cos+12Dk(n)cos(2IFn+)(6)Qk=Dk(n)sin(IFn)sin(IFn+)=12Dk(n)sin+12Dk(n)sin(2IFn+)(7),:=tan-1(QkIk)(8),(PLL),,,(NCO):F(z)=(C1+C2)-C1z-11-z-1(9)NCO:N(z)=K0z-11-z-1(10)PLL:H(z)=K0Kd(C1+C2)z-1-K0KdC1z-21+(K0Kd(C1+C2)-2)z-1+(1-K0KdC1)z-2(11),C1=1K0Kd8nT4+4nT+(nT)2C2=1K0Kd4(nT)24+4nT+(nT)2K0Kd,,n,TGPS31222008:GPS4C/A,GPS,,,,5(45),:[1]DineshManandhar.DevelopmentofL1-BandC/ACodeSoftware-basedGPSReceiver[R].TheUniversityofTo-kyo,2002.[2]JAMESBAO-YENTSUI.FundamentalofGlobalPositio-ningSystemReceivers-ASoftwareApproach[M].NewYork,AWileyIntersciencePublication,2000.[3]ZarlinkGP2015GPSReceiverRFFrontEnd[S].ZarlinkSemiconductorInc,2005.[4]PerGustavsson.DevelopmentofaMatlabbasedGPScon-stellationsimulationfornavigationalgorithmdevelopments[D].LuleaUniversityofTechnology,2005.[5]PeterRinder&NicolajBertelsen.Designofasinglefre-quencyGPSsoftwarereceiver[D].AalborgUniversity,2004.(120)24,,,,,Canny,,,,,:[1]FanJiangping,ZhuXingquan,WuLide.AutomaticMod-el-BasedSemanticObjectExtractionAlgo-tithm[J].IEEETrans.OncircuitsandSystemsforVideoTechnolo-gy,2001,11(10):1073-1084.[2]ToddSchoepflin,ChalanaVikram,Member,IEEE,HaynorDavidR,KinYongmin,Fellow.IEEE.VideoObjectTrackingWithaSequentialHiera-rchyofTemplateDeformations[J].IEEETrans.OncircuitsandSystemsforVideoTechnology,2001,11(11):1173-1182.[3],,.[J].,2002,28(5):72-74.[4]MeierThomas,Member,IEEE,NganKingN,SeniorMember,IEEE.Videosegmentationforcontent-basedcoding[J].IEEE.Trans.onCircuitsandSystemsforVideoTechnology.1999,9(8):1190-1203.[5],,,.[J].,2001,6(8):732-737.1231