82 lines
3.0 KiB
Mathematica
82 lines
3.0 KiB
Mathematica
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%function InitCodePhase=GenerateSatellitesPseudoranges(InitObsTime,DurationTime,LLH,PRNlist,ElevationMask)
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clear all
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addpath ..\include % The software receiver functions
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addpath ..\geoFunctions % Position calculation related functions
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addpath ..
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load trackingResults_HN.mat
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%navSolutions = postNavigation(trackResults, settings);
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%pseudorange=navSolutions.channel.rawP;
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%Gen ephemeris message for every satellite
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[subFrameStart, activeChnList] = findPreambles(trackResults, settings);
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LLH=[21.004498873852768 105.8435979060256 50.956094086170197];
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PRNlist=[3 6 13 16 19 23];
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ElevationMask=10;
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for channelNr = activeChnList
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%=== Convert tracking output to navigation bits =======================
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%--- Copy 5 sub-frames long record from tracking output ---------------
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navBitsSamples = trackResults(channelNr).I_P(subFrameStart(channelNr) - 20 : ...
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subFrameStart(channelNr) + (1500 * 20) -1)';
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%--- Group every 20 vales of bits into columns ------------------------
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navBitsSamples = reshape(navBitsSamples, ...
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20, (size(navBitsSamples, 1) / 20));
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%--- Sum all samples in the bits to get the best estimate -------------
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navBits = sum(navBitsSamples);
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%--- Now threshold and make 1 and 0 -----------------------------------
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% The expression (navBits > 0) returns an array with elements set to 1
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% if the condition is met and set to 0 if it is not met.
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navBits = (navBits > 0);
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%--- Convert from decimal to binary -----------------------------------
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% The function ephemeris expects input in binary form. In Matlab it is
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% a string array containing only "0" and "1" characters.
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navBitsBin = dec2bin(navBits);
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%=== Decode ephemerides and TOW of the first sub-frame ================
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[eph(trackResults(channelNr).PRN), TOW] = ...
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ephemeris(navBitsBin(2:1501)', navBitsBin(1));
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end
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[tmpx tmpy tmpz]=llh2xyz(LLH(1),LLH(2),LLH(3));
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userxyz=[tmpx tmpy tmpz];
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InitObsTime=TOW;
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DurationTime=360;
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obsTime=[InitObsTime:0.001:InitObsTime+DurationTime+1];
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speedOfLight=299792458;
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lengthOfChips=speedOfLight/1.023e6;
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idxTTime=1;
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hwb=waitbar(0,'Please wait');
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distByChips=zeros(length(obsTime),length(PRNlist));
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for transmitTime=obsTime
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if rem(idxTTime,10)==0
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waitbar((transmitTime-obsTime(1))/(obsTime(end)-obsTime(1)),hwb);
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end;
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validPRN=[];
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for PRN=PRNlist;
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if PRN==24
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continue;
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end;
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[satPosition, satClkCorr] = satpos(transmitTime, ...
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PRN, ...
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eph);
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[az, el, tmpDist] = topocent(userxyz', satPosition - userxyz');
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dist=tmpDist-satClkCorr*speedOfLight;
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distByChips(idxTTime,PRN)=dist/lengthOfChips;
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if (el>=ElevationMask)&& (el<=90)
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validPRN=[validPRN PRN];
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end;
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end;
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idxTTime=idxTTime+1;
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end;
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InitCodePhase=distByChips(:,validPRN);
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close(hwb);
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save InitCodePhase InitCodePhase
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