//-----------------------------------------------------------------------------
void RxSim::process()
{
NavFramer nf;
long int dataPoint =0;
int count = 0;
nf.debugLevel = debugLevel;
nf.dump(cout);
complex<float> s;
int b=0;
while (*input >> s)
{
if (b == band-1 || input->bands==1)
{
s *= gain;
if (tr->process(s))
{
if (verboseLevel)
tr->dump(cout);
// Test code to skip input to speed up tracking.
/*int count2 = 0;
while(count2 < 3*16367)
{
count2++;
*input >> s;
}*/
// Following two if statements are specific to tracker updating every
// 1 ms.
if(tr->navChange)
{
nf.process(*tr, dataPoint,
(float)tr->localReplica.getCodePhaseOffsetSec()*1e6);
count = 0;
}
if(count == 20)
{
count = 0;
nf.process(*tr, dataPoint,
(float)tr->localReplica.getCodePhaseOffsetSec()*1e6);
}
count++;
}
}
b++;
b %= input->bands;
if (cc->localTime > timeLimit)
break;
dataPoint++;
}
}
void *Cfunction(void* p)
{
Par *par = (Par*)p;
EMLTracker *tr = par->tr;
int *count = par->count;
NavFramer *nf = par->nf;
int bufferSize = par->bufferSize;
int dp = par->dp - bufferSize;
Buffer *b = par->s;
bool v = par->v;
int index = 0;
while(index < bufferSize + 1) // number of data points to track before join.
{
if (tr->process(b->arr[index]))
{
if(v)
tr->dump(cout);
if(tr->navChange)
{
nf->process(*tr, dp,
(float)tr->localReplica.getCodePhaseOffsetSec()*1e6);
*count = 0;
}
if(*count == 20)
// The *20* depends on the tracker updating every C/A period.
{
*count = 0;
nf->process(*tr, dp,
(float)tr->localReplica.getCodePhaseOffsetSec()*1e6);
}
*count = *count + 1;
}
index++;
dp++;
}
pthread_exit(NULL);
return NULL;
}
bool RxSim::initialize(int argc, char *argv[]) throw()
{
using namespace gpstk::StringUtils;
CommandOptionWithAnyArg
codeOpt('c', "code",
"The code/carrier to track. ARG takes the form of "
"code:carrier:prn:offset:doppler. Code is either c or p. "
"Carrier is either 1 or 2. Prn is an integer between 1 and 32. "
"Offset is a number in us, Doppler is a number in Hz. Currently, "
"only one signal can be specified. For example, to track P code "
"on L2 for PRN 3, with no initial time or doppler offset, "
"specify -c p:2:3:0:0"),
dllAlphaOpt('\0', "dllAlpha",
"The gain on the phase update for the code tracker. The "
"default is 1e-5 chips/tick"),
dllBetaOpt('\0', "dllBeta",
"The gain on the frequency update for the code tracker. The "
"default is 1e-12 chips/tick"),
pllAlphaOpt('\0', "pllAlpha",
"The gain on the phase update for the carrier tracker. The "
"default is 0.4 cycles/tick"),
pllBetaOpt('\0', "pllBeta",
"The gain on the frequency update for the carrier tracker. "
"The default is 0.1 cycles / iad_period"),
sampleRateOpt('r',"sample-rate",
"Specifies the nominal sample rate, in MHz. The "
"default is 20 MHz."),
interFreqOpt('x',"inter-freq",
"Specifies the intermediate frequency of the receiver,"
" in MHz. Default is 0.42 MHz. If there is no down-"
"conversion, the IF should be the L1 or L2 carrier"
" frequency" ),
quantizationOpt('q', "quantization",
"They quantization applied to the data. 1, 2 or f. "
"The default is f."),
gainOpt('g', "gain",
"Gain to apply to the if prior to digitization, in dB. Default is 0."),
timeLimitOpt('t', "time-limit",
"Limit the amount of data to process. Specify time in ms. Defaults to all data."),
inputOpt('i', "input",
"Where to get the IQ samples from. The default is to use stdin.");
CommandOptionWithNumberArg
bandsOpt('b', "bands",
"The number of complex samples per epoch. The default is 2.");
if (!BasicFramework::initialize(argc,argv))
return false;
if (timeLimitOpt.getCount())
timeLimit = asDouble(timeLimitOpt.getValue()[0]) * 1e-3;
if (!codeOpt.getCount())
{
cout << "Must specify a code/carrier to track. Bye." << endl;
return false;
}
string val=codeOpt.getValue()[0];
const char delim(':');
if (numWords(val, delim) != 5)
{
cout << "Error in code parameter:" << val << endl;
return false;
}
string code = lowerCase(word(val, 0, delim));
band = asInt(word(val, 1, delim));
int prn = asInt(word(val, 2, delim));
double offset = asDouble(word(val, 3, delim)) * 1e-6;
double doppler = asDouble(word(val, 4, delim));
CodeGenerator* codeGenPtr;
double chipFreq;
switch (code[0])
{
case 'c':
codeGenPtr = new CACodeGenerator(prn);
chipFreq = CA_CHIP_FREQ_GPS;
break;
case 'p':
codeGenPtr = new PCodeGenerator(prn);
chipFreq = PY_CHIP_FREQ_GPS;
break;
default:
cout << "Unsupported code: " << code << endl;
return false;
}
if (sampleRateOpt.getCount())
timeStep = 1/(asDouble(sampleRateOpt.getValue().front()) * 1e6 );
if (interFreqOpt.getCount())
interFreq = asDouble(interFreqOpt.getValue().front()) * 1e6;
// Note that this object is responsible for destroying
// the codeGenPtr object
cc = new CCReplica(timeStep, chipFreq, interFreq, codeGenPtr);
double chips = offset / cc->codeChipLen;
cc->moveCodePhase(chips);
cc->setCodeFreqOffsetHz(doppler);
cc->setCarrierFreqOffsetHz(doppler);
double spacing = 0.5 * cc->codeChipLen;
if (spacing < timeStep)
spacing = timeStep;
tr = new EMLTracker(*cc, spacing);
if (dllAlphaOpt.getCount())
tr->dllAlpha = asDouble(dllAlphaOpt.getValue()[0]);
if (dllBetaOpt.getCount())
tr->dllBeta = asDouble(dllBetaOpt.getValue()[0]);
if (pllAlphaOpt.getCount())
tr->pllAlpha = asDouble(pllAlphaOpt.getValue()[0]);
if (pllBetaOpt.getCount())
tr->pllBeta = asDouble(pllBetaOpt.getValue()[0]);
tr->debugLevel = debugLevel;
char quantization='f';
if (quantizationOpt.getCount())
quantization = quantizationOpt.getValue()[0][0];
switch (quantization)
{
case '1': input = new IQ1Stream(); break;
case '2': input = new IQ2Stream(); break;
case 'f':
default: input = new IQFloatStream(); break;
}
if (inputOpt.getCount())
{
input->open(inputOpt.getValue()[0].c_str());
}
else
{
using std::basic_ios;
input->copyfmt(std::cin);
input->clear(std::cin.rdstate());
input->basic_ios<char>::rdbuf(std::cin.rdbuf());
input->filename = "<stdin>";
}
if (bandsOpt.getCount())
input->bands = asInt(bandsOpt.getValue()[0]);
if (gainOpt.getCount())
{
double gainDb = StringUtils::asDouble(gainOpt.getValue()[0]);
gain = exp10(gainDb/10.);
}
if (verboseLevel)
{
cout << "# Taking input from " << input->filename
<< " (" << input->bands << " samples/epoch)" << endl
<< "# Rx gain level: " << gain << endl;
tr->dump(cout, 1);
}
return true;
}
long int NavFramer::process(const EMLTracker& tr, long int dp, float cPO)
{
// number of code chips that go into each bit
const unsigned long chipsPerBit =
static_cast<unsigned long>(bitLength / tr.localReplica.codeChipLen);
const CodeIndex now = tr.localReplica.codeGenPtr->getChipCount();
const unsigned navCount = now/chipsPerBit;
// Code below can be uncommented if the NavFramer needs to count on it's own
// to know when there is a new nav bit. Right now it is only called when the
// tracker says there is one.
/*
if (navCount == prevNavCount)
{
//cout << "skipping" << endl;
return howCurrent;
}
*/
//cout << "doing" << endl;
howCurrent = false;
prevNavCount = navCount;
navBuffer[navIndex] = tr.getNav();
codeIndex[navIndex] = now;
startDP.push_back(dp);
codePO.push_back(cPO);
navIndex++;
navIndex %= navBuffer.size();
lastEight <<= 1;
lastEight[0] = tr.getNav();
if (debugLevel>2)
cout << "# t:" << fixed << setprecision(2)
<< tr.localReplica.localTime *1e3
<< " ms, n:" << tr.getNav() << endl;
if (lastEight == eightBaker || ~lastEight == eightBaker)
{
//cout << "FOUND CANDIDATE" << endl ;
Subframe sf;
sf.ni = (navIndex-8) % 1500;
sf.ci = codeIndex[sf.ni];
sf.dataPoint = startDP[sf.ni];
sf.prn = tr.prn;
sf.codePO = codePO[sf.ni];
sf.prevD30 = navBuffer[(navIndex-9)%1500];
sf.t = tr.localReplica.localTime;
sf.inverted = lastEight != eightBaker;
if (debugLevel>1)
cout << "# " << sf << endl;
candidates.push_back(sf);
}
list<Subframe>::iterator sf;
for (sf = candidates.begin(); sf != candidates.end(); )
{
if (navIndex - sf->ni >= 300)
{
sf->load(navBuffer);
if (sf->checkParity())
{
subframes.push_back(*sf);
how = sf->words[1];
//if (debugLevel)
//cout << *sf << endl;
//if (debugLevel)
//sf->dump(cout,1);
howCurrent = true;
// Following block pulls nav data from subframes, just playing around for now.
/*
long framesArrayFormat[10];
int gpsWeek = 1433;
double output[60];
for(int k = 0; k < 10; k++)
{
framesArrayFormat[k] = sf->words[k];
}
EngNav::subframeConvert(framesArrayFormat, gpsWeek, output);
for(int i = 0; i < 60; i++)
cout << output[i] << endl;
*/
}
else
{
howCurrent = false;
if (debugLevel>1)
{
cout << "# " << *sf << endl;
sf->dump(cout, 1);
}
}
candidates.erase(sf++);
}
else
sf++;
}
return howCurrent;
}
