84 lines
2.9 KiB
Mathematica
84 lines
2.9 KiB
Mathematica
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%Check autocorrelation
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clear; close all; clc;
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format ('compact');
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format ('long', 'g');
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%--- Include folders with functions ---------------------------------------
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addpath include % The software receiver functions
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addpath geoFunctions % Position calculation related functions
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CodePhase =-1:0.001:1; %[chips]
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caCode = generateCAcode(1);
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%caCode = [caCode caCode caCode];
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codeFreq = 1.023e6;
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earlyLateSpc = 0.5;
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Td = 0.001;
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idxSamplingFreq = 1;
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samplingFreqRange = [4]*1.023e6;
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varDLLError = size(1,length(samplingFreqRange));
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maxDLLError = varDLLError;
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minDLLError =varDLLError;
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for samplingFreq = samplingFreqRange;
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codePhaseStep = codeFreq / samplingFreq;
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blksize = Td*samplingFreq;
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tcode = 0:codePhaseStep : ((blksize-1)*codePhaseStep);
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%tcode2 =ceil(tcode)+1023;
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tcode2 = floor(rem(tcode+1023,1023)) + 1;
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incomingSignal = caCode(tcode2);
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I_E=size(1,length(CodePhase));
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I_P=I_E;
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I_L=I_E;
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idxCodePhase=1;
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for remCodePhase=CodePhase
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tcode = (remCodePhase-earlyLateSpc) : ...
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codePhaseStep : ...
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((blksize-1)*codePhaseStep+remCodePhase-earlyLateSpc);
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tcode2 = floor(rem(tcode+1023,1023)) + 1;
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%tcode2 =ceil(tcode)+1023;
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earlyCode = caCode(tcode2);
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% Define index into late code vector
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tcode = (remCodePhase+earlyLateSpc) : ...
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codePhaseStep : ...
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((blksize-1)*codePhaseStep+remCodePhase+earlyLateSpc);
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tcode2 = floor(rem(tcode+1023,1023)) + 1;
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%tcode2 =ceil(tcode)+1023;
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lateCode = caCode(tcode2);
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% Define index into prompt code vector
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tcode = remCodePhase : ...
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codePhaseStep : ...
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((blksize-1)*codePhaseStep+remCodePhase);
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tcode2 = floor(rem(tcode+1023,1023)) + 1;
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%tcode2 =ceil(tcode)+1023;
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promptCode = caCode(tcode2);
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I_P(idxCodePhase)=sum(promptCode.*incomingSignal)/blksize;
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I_L(idxCodePhase)=sum(lateCode.*incomingSignal)/blksize;
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I_E(idxCodePhase)=sum(earlyCode.*incomingSignal)/blksize;
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idxCodePhase =idxCodePhase+1;
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%Code Error
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end;
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figure(300);
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plot(CodePhase,I_P,'r','LineWidth',2);grid on;hold on;
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disp(sprintf('Processing Fs =%d',samplingFreq));
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codeError=(I_E-I_L)./(2*(I_E+I_L))- CodePhase;
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codeError2=codeError(find(CodePhase>=-0.5 & CodePhase<=0.5));
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minDLLError(idxSamplingFreq) = min(abs(codeError2));
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maxDLLError(idxSamplingFreq) = max(codeError2);
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varDLLError(idxSamplingFreq) = var(abs(codeError2));
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idxSamplingFreq = idxSamplingFreq+1;
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end;
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figure(100);
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plot(samplingFreqRange/1.023e6,sqrt(varDLLError)*299792458/codeFreq,'-o');grid on;
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