simulatedDataDuration = 3;%秒samplingRate = 10.23e6;% (Hz)

WriteWaveformToFile =假；

stepTime = 1e-3;%秒numSteps = (simulatedDataDuration/stepTime) + 1;

rinexFileName =“GODS00USA_R_20211750000_01D_GN.rnx”；almanacFileName =“gpsAlmanac.txt”；rinexdata = rinexread(rinexFileName);

Rxlat = 39.021;以北纬为单位Rxlon = -76.827;以东经度为单位的经度;负经度是西经度Rxel = 19;海拔百分比(米)

numCACodeBlocksPerBit = 20;

rxWaitTime = 100;%毫秒performInitSync = true;最初必须设置为true初始化跟踪通道的最大数量。最少4个跟踪%信道是GPS接收机正常工作所必需的。maxNumTrackingChannels = 8;%每个跟踪循环的噪声带宽PLLNoiseBW = 90;% (Hz)FLLNoiseBW = 4;% (Hz)DLLNoiseBW = 3;% (Hz)位同步参数isBitSyncComplete = 0 (maxNumTrackingChannels,1);numBitsForBitSync = 100;numWaitingStepsForBitSync = numCACodeBlocksPerBit*numBitsForBitSync;RXCNTR = 1;

minTimeForPosEst = 48.5;%秒minStepsForPosEst = minTimeForPosEst/stepTime;subframeDuration = 6;%秒numStepsPerSubframe = subframeDuration/stepTime;

C = physconst(“光速”）;光速的%，单位为m/sFe = 1575.42e6;% GPS L1频率，单位为HzDt = 12;%发射天线指向性，单位为dBiDtLin = db2pow(Dt);Dr = 4;%接收天线指向性，单位为dBiDrLin = db2pow(Dr);Pt = 44.8;GPS卫星的典型传输功率(瓦特)K = physconst(“波尔兹曼”）;%玻尔兹曼常数，单位为焦耳/开尔文T = 300;室温(开尔文)rxBW = 24e6;%带宽(Hz)Nr = k*T*rxBW;%热噪声功率(瓦特)rng默认的；初始化为默认随机数生成

初始化卫星场景sc = satellite场景;根据RINEX数据设置卫星卫星=卫星(sc,rinexdata，“OrbitPropagator”，“全球定位系统”）;rx =地面站(sc,rxlat,rxlon);设置接收器Ac = access(sat,rx);计算卫星和接收器之间的访问从中获取卫星场景中考虑的卫星列表% RINEX数据indexes = ones(length(sat)，1);为isat = 1:长度(sat) ele =轨道元素(sat(isat));检查适用性时间与伪随机噪声是否匹配% (PRN)标识，以便RINEX文件中的数据被视为波形%的一代indexes (isat) = find(rinexdata.GPS(:，:)。脚趾== ele。GPSTimeOfApplicability &.．.rinexdata.GPS(:,:)。卫星id == le. prn);结束

生成导航配置对象navcfg = HelperGPSRINEX2Config(almanacFileName,rinexdata.GPS(indices，:));[mintow,locmintow] = min([navcfg(:).HOWTOW]);每周时间(TOW)值必须是1加上的倍数% 5，因此子帧1的数据总是先生成。Mintow = ceil((Mintow -1)/5)*5 + 1;% HOWTOW是一个包含整数值的计数器。递增一个值%的1表示6秒的数据。计数器增加1的值%用于每个新子帧。[navcfg(:)。HOWTOW] =交易(mintow);设置基于mintow的帧开始firstsubframeID = mod(mintow-1,125) + 1;frameID = ceil(firstsubframeID/5);allframeid = [frameID:25,1:(frameID-1)];[navcfg(:)。frameindexes] = deal(allframeid);生成GPS导航数据numNavBits = 37500;%完整GPS数据长度为37500位navdata = 0 (numNavBits，长度(navcfg));为isat = 1:length(navcfg) navdata(:，isat) = HelperGPSNAVDataEncode(navcfg(isat));结束

sc.StartTime = HelperGPSConvertTime(navcfg(locmintow). ceidatset . weeknumber，.．.mintow * subframeDuration);sc.StopTime = sc.StartTime + seconds(simulatedDataDuration);sc.SampleTime = stepTime;acstats = accessStatus(ac);这个例子最多运行2分钟的数据%持续时间，访问不会改变。因此，只考虑访问状态第一次采样时间的%。Satindices = find(acstats(:，1));Numsat =长度(satindices);获取天空中卫星随时间变化的状态。[initsatpos,satvel] = state (sat，“CoordinateFrame”，“ecef”）;打乱维度，使每一行对应一个卫星数据Initsatpos = permute(Initsatpos，[3,1,2]);Satvel = permute(Satvel，[3,1,2]);

计算所有可见卫星随时间的多普勒偏移[az,el] = aer(sat(satindices)，rx);[~，satV] = state (sat(satindices)，CoordinateFrame=“地理”）;Dir = cat(1,permute(cosd(el).*cosd(az)，[3 2 1])，.．.Permute (cosd(el).*sind(az)，[3 2 1])，.．.Permute (-sind(el)，[3 2 1]);dopV = permute(dot(satV,dir)，[3 2 1]);fo = ((c./(c-dopV))*fe).';%观察频率fShift = (fo - fe);%所有可见卫星随时间的多普勒频移计算卫星与接收机之间随时间的距离。satdist = 0 (numSteps,numsat);为istep = 1:numSteps satdist(istep，:) = pseudoranges([rxlat,rxlon,rxel]，.．.initsatpos (satindices: istep),“RangeAccuracy”, 0);结束延迟= satdist/c;从自由空间路径损失方程得到的接收机功率%SqrtPr = sqrt (Pt * DtLin * DrLin) * (c /(4 *π* fo。* satdist));Timeinweek = mintow*6;prnid = [navcfg(:).PRNID];disp (“可用的卫星——”+ num2str (PRNIDs (satindices)))

cacodes = gnssccode (PRNIDs，“全球定位系统”）;caCodeBlockDuration = 1e-3;恒定值numcacodeblocks = stepTime/caCodeBlockDuration;每个C/ a代码块的持续时间为1毫秒要使C/A-code与P-code匹配，每个元素重复10次Cacodesig1 = double(repelem(1-2*repmat(cacodes,numcacodeblocks,1)，10,1));将C/ a代码与采样率匹配[upfac,downfac] = rat(samplingRate/10.23e6);Upcacodesig = repelem(cacodesig1,upfac,1);Cacodesig = upcacodesig(1:downfac:end，:);

numSamples = stepTime*samplingRate;pcode = (1 - 2 * repmat ((1, 0), numSamples / 2, 1)) /√(2);

pfo = com . phasefrequencyoffset (FrequencyOffsetSource =“输入端口”，.．.SampleRate = samplingRate);

初始化静态延迟对象dynamicDelayRange = 20000;staticdelay = round(延迟(1，:)*samplingRate - dynamicDelayRange);如果Nnz (staticdelay<0)~=0 staticdelay =0 (1,numsat);结束staticDelayObj = dsp。延迟(“长度”, staticdelay);初始化可变分数延迟对象，用于建模动态延迟VFD = dsp。VariableFractionalDelay (“InterpolationMethod”，“法罗”，.．.“MaximumDelay”, 65535);

rxconstellation = com . constellationdiagram (1,ShowReferenceConstellation=false，.．.Title =“跟踪输出信号星座图”）;

initialsync = HelperGPSInitialSynchronization;最初搜索全部32颗卫星initialsync。PRNIDsToSearch = 1:32;initialsync。SampleRate = samplingRate;initialsync。CenterFrequency = 0%基带信号

如果WriteWaveformToFile == 1 bbWriter = com . basebandfilewriter (“gpsBBWaveform.bb”samplingRate 0);结束

存储初始同步输出的属性[doppleroffsets,codephoffsets] = deal(零(1,maxNumTrackingChannels));存储跟踪模块输出所需的属性[accuPh, accuFqy accuFqyErr、accuPhErr accuIntegWave, accuDelay, accuDelayErr] =.．.协议(0 (numSteps maxNumTrackingChannels));属性存储位同步和帧的输出%的同步[maxTransitionLocation,sampleCounter] = deal(零(maxNumTrackingChannels,1));syncidx = 0 (maxNumTrackingChannels,1);属性存储数据解码器的输出deccfg = cell(maxNumTrackingChannels,1);初始化模拟链运行的最大步数maxSimSteps = 50/stepTime;

抽搐%开始模拟numAx = size(initsatpos,2);为istep = 1:numSteps生成波形bitidx = floor((istep-1)/numCACodeBlocksPerBit)+1;Allpcode = repmat(pcode,1,numsat);%获取每颗卫星对应步长时间的导航位Navbitsig = 1-2*navdata(bitidx,satindices);Iqsig = (allpcode + 1j*cacodesig(:，satindices)).*navbitsig;隐式展开%%传播通道建模用于模拟多普勒、延迟、路径损耗和噪声的信道%信号将多普勒引入信号作为频率偏移dopsig = pfo(iqsig,fShift(istep，:));引入可变分数延迟staticDelayedSignal = staticDelayObj(dopsig);leftoutDelay = delay (istep，:)*samplingRate - staticdelay;%值必须始终为正delayedSig = vfd(staticDelayedSignal,leftoutDelay);%按接收功率计算计算延迟信号rmsPow = rms(delayedSig);(rmsPow==0) = 1;避免除零scaledsig = SqrtPr(istep，:).*delayedSig./rmsPow;把接收机上的所有信号加起来。Resultsig = sum(scaledsig,2);%产生噪音noisesig = (wgn(numSamples,1,10*log10(Nr)) + 1j*wgn(numSamples,1,10*log10(Nr)))./√(2);在复合信号中添加恒定的热噪声rx波形=结果信号+噪声信号;将接收到的信号缩放为具有单位功率波形= rx波形/rms(rx波形);如果WriteWaveformToFile == 1 bbWriter(波形);结束timeinweek = timeinweek + stepTime;% %接收机因为有很大的延迟(70到80毫秒)%信号，启动接收器一段时间后才进行处理%有效信号，而不是纯噪声。如果istep > rxWaitTime如果performInitSync == 1;[y,corrval] = initialsync(波形);%初始同步PRNIDsToSearch = y(y(:，4)==1,1).';doppleroffset = y(y(:，4)==1,2).';Codephoffsets = y(y(:，4)==1,3).';numdetectsat =长度(PRNIDsToSearch);如果numdetectsat > maxNumTrackingChannels设置此值可限制跟踪通道的数量numdetectsat = maxNumTrackingChannels;结束为每个跟踪模块执行所需的初始化%通道和缓冲区来存储数据。disp ("探测到的卫星PRN id: "+ num2str (PRNIDsToSearch))绘制第一颗卫星的相关图图;net (-10e3:500:10e3, 0:size(corrval,1)-1, corrval(:，:，PRNIDsToSearch(1)));包含(“多普勒偏移量”) ylabel (“码相位偏移”) zlabel (“相关”) MSG = [PRN ID的相关图:num2str (PRNIDsToSearch (1)];Title (msg) framesyncbuffer = cell(1,numdetectsat);创建一个单元格数组，其中每个元素对应一个载体%跟踪对象。carrierCodeTrack = cell(numdetectsat,1);framessync = cell(numdetectsat,1);更新每个跟踪循环的属性为isat = 1:numdetectsat carrierCodeTrack{isat} = HelperGPSCACodeCarrierTracker;carrierCodeTrack{成绩测试标准}。SampleRate = samplingRate;carrierCodeTrack{成绩测试标准}。CenterFrequency = 0;carrierCodeTrack{成绩测试标准}。PLLNoiseBandwidth = PLLNoiseBW;carrierCodeTrack{成绩测试标准}。FLLNoiseBandwidth = FLLNoiseBW;carrierCodeTrack{成绩测试标准}。DLLNoiseBandwidth = DLLNoiseBW; carrierCodeTrack{isat}.PLLIntegrationTime = 1;%单位为毫秒carrierCodeTrack{成绩测试标准}。PRNID = PRNIDsToSearch(isat);carrierCodeTrack{成绩测试标准}。InitialDopplerShift = doppleroffset (isat);carrierCodeTrack{成绩测试标准}。InitialCodePhaseOffset = codephoffsets(isat);初始化帧同步对象framesync{isat} = HelperGPSLNAVFrameSynchronizer;结束结束%因为它将足够得到接收器位置之后%运行模拟50秒的数据，停止循环%后执行50秒的数据。的默认运行%例如，只有3秒的数据被处理，而这一行没有%。该检查是在运行大数据示例时进行的%持续时间(至少50秒的数据)。如果istep > maxSimSteps打破；结束为Isat = 1:numdetectsat对每颗卫星执行跟踪[integwave, fqyerr fqyoffset、pherr phoffset, derr, dnco] =.．.carrierCodeTrack{成绩测试标准}(波形);累加值以查看最后的结果accuFqyErr(rxcntr,isat) = fqyerr;accuFqy(rxcntr,isat) = fqyoffset;accuPhErr(rxcntr,isat) = pherr;accuPh(rxcntr,isat) = phoffset;accuIntegWave(rxcntr,isat) = sum(integwave);accuDelayErr(rxcntr,isat) = derr;accuDelay(rxcntr,isat) = dnco;结束执行位同步、帧同步和数据如果接收端步骤的numWaitingStepsForBitSync为%完成。如果rxcntr > numWaitingStepsForBitSync对每颗探测到的卫星进行位同步，帧同步和数据解码为Isat = 1:numdetectsat如果~isBitSyncComplete(isat) maxTransitionLocation(isat) =.．.gnssBitSynchronize (.．.图像放大(accuIntegWave (1: numWaitingStepsForBitSync,成绩测试标准)),.．.numCACodeBlocksPerBit);isBitSyncComplete(isat) = 1;sampleCounter(isat) = rxcntr - maxTransitionLocation(isat) + 1;framesyncbuffer{isat} = accuIntegWave(.．.maxTransitionLocation(成绩测试标准):结束,成绩测试标准);其他的执行帧同步和数据解码sampleCounter(isat) = sampleCounter(isat) + 1;framesyncbuffer{isat}(sampleCounter(isat)) = accuIntegWave(rxcntr,isat);如果mod(sampleCounter(isat)，numStepsPerSubframe) == 0 samples = framesyncbuffer{isat}(sampleCounter(isat) -.．.numStepsPerSubframe + 1: sampleCounter(成绩测试标准));sym = mean(重塑(样本，numCACodeBlocksPerBit，[]));Bits = imag(sym)<0;[syncidx(isat)，rxsubframes,subframeIDs] = framesync{isat}(bits(:));如果~ isempty (rxsubframes)%，执行数据解码deccfg{成绩测试标准}。PRNID = PRNIDsToSearch(isat);deccfg{isat} = HelperGPSLNAVDataDecode(rxsubframes,deccfg{isat});结束结束结束结束结束如果Mod (rxcntr,1000) == 0 disp(“加工”+ (rxcntr/1000) +“接收端的SEC数据。”) rxconstellation (accuIntegWave (rxcntr - 999: rxcntr, 1) /.．.rms (accuIntegWave (rxcntr - 999: rxcntr 1)))结束%更新rxcntrRXCNTR = RXCNTR + 1;结束结束

如果WriteWaveformToFile == 1 release(bbWriter);结束e2eTime = toc;disp (“端到端链跑”e2eTime +“秒”。)

caChipRate = 1.023e6;% (Hz)codeOffsetTime = codephoffsets(1:numdetectsat)/caChipRate;Rxcntr (Rxcntr <=1) = 2;所以rxcntr-1至少是trackingOffsetTime = accuDelay(rxcntr-1,1:numdetectsat)/caChipRate;bitsyncTime = (maxTransitionLocation(1:numdetectsat) - 1)*caCodeBlockDuration;framesyncTime = (syncidx(1:numdetectsat)-1)*numCACodeBlocksPerBit*caCodeBlockDuration;根据这些参数计算传输时间tt1 = codeOffsetTime(:) - trackingOffsetTime(:) + bitsyncTime + framesyncTime;Tt1 = Tt1 (syncidx~=0);

Trtemp = max(tt1);Row = (tt1-trtemp)*c;包括从接收到的导航消息解码的一周时间tow = 0 (maxNumTrackingChannels,1);为isat = 1:maxNumTrackingChannels如果isfield (deccfg{成绩测试标准},“HOWTOW”) tow(isat) = (deccfg{isat}.)1)*6;每个子帧的持续时间为6秒结束结束拖=拖(syncidx~=0);%偏移估计传输时间。这个偏移量是根据经验得出的。timeOffset = 0.74;tt = tt1 + tow + timeOffset;

Deccfg1 = deccfg(syncidx~=0);只有接收机至少处理完毕，才能估计卫星位置。% minStepsForPosEst数据isFullDataDecoded = true(长度(tt)，1);如果rxcntr > minStepsForPosEst [timeofweek,SatelliteID,Delta_n,M0,Eccentricity,sqrtA,Toe,Toc,Cis,Cic,Crs,Crc,Cus,Cuc，.．.OMEGA0,i0, OMEGA_DOT,IDOT,GPSWeek] = deal(0 (4,1));reqCEIFields = [“WeekNumber”，“ReferenceTimeOfEphemeris”，“ReferenceTimeOfClock”，.．.“SemiMajorAxisLength”，“MeanMotionDifference”，“MeanAnomaly”，“偏心”，.．.“ArgumentOfPerigee”，“倾向”，“InclinationRate”，“HarmonicCorrectionTerms”，.．.“RateOfRightAscension”，“LongitudeOfAscendingNode”]；为Isat = 1:长度(tt)每周时间(Isat) = tt(Isat);isFullDataDecoded(isat) = (isfield(deccfg1{isat}，“PRNID”) & &.．.(所有(isfield (deccfg1{成绩测试标准}.CEIDataSet, reqCEIFields)));如果isFullDataDecoded(isat) satellite iteid (isat) = deccfg1{isat}.PRNID;GPSWeek(isat) = deccfg1{isat}. ceidatset . weeknumber;脚趾(isat) = deccfg1{isat}. ceidatset . referencetimeoffephemeris;Toc(isat) = deccfg1{isat}. ceidatset . referencetimeofclock;sqrtA(isat) = sqrt(deccfg1{isat}.CEIDataSet.SemiMajorAxisLength);Delta_n(isat) = deccfg1{isat}. ceidatset . meanmotiondifference *pi;M0(isat) = deccfg1{isat}.CEIDataSet.MeanAnomaly*pi;偏心量(isat) = deccfg1{isat}. ceidatset .偏心量;omega(isat) = deccfg1{isat}.CEIDataSet.ArgumentOfPerigee*pi;i0(isat) = deccfg1{isat}. ceidatset .倾角*pi; IDOT(isat) = deccfg1{isat}.CEIDataSet.InclinationRate*pi; hterms = num2cell(deccfg1{isat}.CEIDataSet.HarmonicCorrectionTerms); [Cis(isat),Cic(isat),Crs(isat),Crc(isat),Cus(isat),Cuc(isat)] = deal(hterms{:}); OMEGA_DOT(isat) = deccfg1{isat}.CEIDataSet.RateOfRightAscension*pi; OMEGA0(isat) = deccfg1{isat}.CEIDataSet.LongitudeOfAscendingNode*pi;结束结束transmissionTime = HelperGPSConvertTime(GPSWeek(isFullDataDecoded)，timeofweek(isFullDataDecoded));refTime = HelperGPSConvertTime(GPSWeek(:)，Toc(:));rx时间表=时间表(refTime，卫星id,Delta_n,M0，偏心量，sqrtA，.．.脚趾,独联体,中投,Crs, Crc Cus、中联科利,₀,钱数,ω,.．.OMEGA_DOT、IDOT GPSWeek);[satpos, satvel] = gnssconstellation(transmissionTime(1)， rxtimeline);结束

如果rxcntr <= minStepsForPosEst此处加载的参数对默认值有效%配置本例负载receiverPositionProperties；加载默认配置的参数时，更新% isFullDataDecoded变量，使用所有的1来计算接收器%的位置。isFullDataDecoded = true(长度(行)，1);defaultRINEXFileName =“GODS00USA_R_20211750000_01D_GN.rnx”；defaulultrxpos = [39.021， -76.827, 19];exampleRxPos = [rxlat, rxlon, rxel];如果~(strcmp(rinexFileName, defaulultrinexfilename) && isequal(defaulultrxpos,exampleRxPos)) warning(“卫星通信:EndToEndGPSLNAVReceiverExample: InsufficientData”，.．.“估计的接收器位置可能与您提供的不同”+.．.“因为模拟并没有运行完整的数据。”+.．."要获得准确的接收器位置，请运行示例"+.．.“至少50秒的导航数据。”）;结束结束计算接收器位置rxposest = receiverposition(row(isFullDataDecoded)，satpos(isFullDataDecoded，:))

estRxPosNED = lla2ned(rxposest，[rxlat,rxlon,rxel]，“椭球体”）;distanceError = vecnorm(estRxPosNED)%(米)