//------------------------------------------------------------------------------
// receive() -- process received emissions
//------------------------------------------------------------------------------
void Radar::receive(const LCreal dt)
{
BaseClass::receive(dt);
// Can't do anything without an antenna
if (getAntenna() == nullptr) return;
// Clear the next sweep
csweep = computeSweepIndex( static_cast<LCreal>(Basic::Angle::R2DCC * getAntenna()->getAzimuth()) );
clearSweep(csweep);
// Compute noise level
// CGB moved here from RfSystem
// Basically, we're simulation Hannen's S/I equation from page 356 of his notes.
// Where I is N + J. J is noise from jamming.
// Receiver Loss affects the total I, so we have to wait until this point to account for it.
const LCreal interference = (getRfRecvNoise() + jamSignal) * getRfReceiveLoss();
const LCreal noise = getRfRecvNoise() * getRfReceiveLoss();
currentJamSignal = jamSignal * getRfReceiveLoss();
int countNumJammedEm = 0;
// ---
// Process Returned Emissions
// ---
Emission* em = nullptr;
LCreal signal = 0;
// Get an emission from the queue
lcLock(packetLock);
if (np > 0) {
np--; // Decrement 'np', now the array index
em = packets[np];
signal = signals[np];
}
lcUnlock(packetLock);
while (em != nullptr) {
// exclude noise jammers (accounted for already in RfSystem::rfReceivedEmission)
if (em->getTransmitter() == this || (em->isECM() && !em->isECMType(Emission::ECM_NOISE)) ) {
// compute the return trip loss ...
// Compute signal received
LCreal rcs = em->getRCS();
// Signal Equation (Equation 2-7)
LCreal rl = em->getRangeLoss();
signal *= (rcs * rl);
// Integration gain
signal *= rfIGain;
// Range attenuation: we don't want the strong signal from short range targets
LCreal maxRng = getRange() * Basic::Distance::NM2M;
//LCreal maxRng4 = (maxRng*maxRng*maxRng*maxRng);
//LCreal rng = (em->getRange());
const LCreal s1 = 1.0;
//if (rng > 0) {
// LCreal rng4 = (rng*rng*rng*rng);
// s1 = (rng4/maxRng4);
// if (s1 > 1.0f) s1 = 1.0f;
//}
signal *= s1;
if (signal > 0.0) {
// Signal/Noise (Equation 2-9)
const LCreal signalToInterferenceRatio = signal / interference;
const LCreal signalToInterferenceRatioDbl = 10.0f * lcLog10(signalToInterferenceRatio);
const LCreal signalToNoiseRatio = signal / noise;
const LCreal signalToNoiseRatioDbl = 10.0f * lcLog10(signalToNoiseRatio);
//std::cout << "Radar::receive(" << em->getTarget() << "): ";
//std::cout << " pwr=" << em->getPower();
//std::cout << " gain=" << em->getGain();
//std::cout << " rl=" << rl;
//std::cout << " rcs=" << rcs;
//std::cout << " signal=" << signal;
//std::cout << " recvN=" << getRfRecvNoise();
//std::cout << " signalToInterferenceRatio=" << signalToInterferenceRatio;
//std::cout << " signalToInterferenceRatioDbl=" << signalToInterferenceRatioDbl;
//std::cout << " thrs=" << getRfThreshold();
//std::cout << std::endl;
// Is S/N above receiver threshold and within 125% of max range?
// CGB, if "signal <= 0.0", then "signalToInterferenceRatioDbl" is probably invalid
// we should probably do something smart with "signalToInterferenceRatioDbl" above as well.
lcLock(myLock);
if (signalToInterferenceRatioDbl >= getRfThreshold() && em->getRange() <= (maxRng*1.25) && rptQueue.isNotFull()) {
// send the report to the track manager
em->ref();
rptQueue.put(em);
rptSnQueue.put(signalToInterferenceRatioDbl);
//std::cout << " (" << em->getRange() << ", " << signalToInterferenceRatioDbl << ", " << signalToInterferenceRatio << ", " << signalToInterferenceRatioDbl << ")";
// Save signal for real-beam display
int iaz = csweep;
int irng = computeRangeIndex( em->getRange() );
sweeps[iaz][irng] += (signalToInterferenceRatioDbl/100.0f);
vclos[iaz][irng] = em->getRangeRate();
} else if (signalToInterferenceRatioDbl < getRfThreshold() && signalToNoiseRatioDbl >= getRfThreshold()) {
countNumJammedEm++;
}
lcUnlock(myLock);
}
}
em->unref(); // this unref() undoes the ref() done by RfSystem::rfReceivedEmission
em = nullptr;
//if (np >= 0 && np < MAX_EMISSIONS) {
// packets[np] = 0;
// signals[np] = 0;
//}
// Get another emission from the queue
lcLock(packetLock);
if (np > 0) {
np--;
em = packets[np];
signal = signals[np];
}
lcUnlock(packetLock);
}
//std::cout << std::endl;
numberOfJammedEmissions = countNumJammedEm;
// Set interference signal back to zero
jamSignal = 0;
}
//------------------------------------------------------------------------------
// receive() -- process received emissions
//------------------------------------------------------------------------------
void Rwr::receive(const LCreal dt)
{
BaseClass::receive(dt);
// clear the back buffer
clearRays(0);
// Receiver losses
#if 0
LCreal noise = getRfRecvNoise();
#else
LCreal noise = getRfRecvNoise() * getRfReceiveLoss();
#endif
// Process received emissions
TrackManager* tm = getTrackManager();
Emission* em = 0;
LCreal signal = 0;
// Get an emission from the queue
lcLock(packetLock);
if (np > 0) {
np--; // Decrement 'np', now the array index
em = packets[np];
signal = signals[np];
}
lcUnlock(packetLock);
while (em != 0) {
//std::cout << "Rwr::receive(" << em->getOwnship() << "): ";
//std::cout << " pwr=" << em->getPower();
//std::cout << " gain=" << em->getGain();
//std::cout << " rl=" << rl;
//std::cout << " pulses=" << pulses;
//std::cout << " losses=" << losses;
//std::cout << " signal=" << signal;
//std::cout << " recvN=" << getRfRecvNoise();
//std::cout << " sn=" << sn;
//std::cout << " snDbl=" << snDbl;
//std::cout << " thrs=" << getRfThreshold();
//std::cout << std::endl;
// CGB, if "signal <= 0.0", then "snDbl" is probably invalid
if (signal > 0.0 && dt != 0.0) {
// Signal over noise (equation 3-5)
LCreal sn = signal / noise;
LCreal snDbl = 10.0f * lcLog10(sn);
// Is S/N above receiver threshold ## dpg -- for now, don't include ECM emissions
if (snDbl > getRfThreshold() && !em->isECM() && rptQueue.isNotFull()) {
// Send report to the track manager
if (tm != 0) {
tm->newReport(em, snDbl);
}
// Get Angle Of Arrival
LCreal aoa= em->getAzimuthAoi();
// Store received power for real-beam display
LCreal sigDbl = 10.0f * lcLog10(signal);
LCreal signal10 = (sigDbl + 50.0f)/50.f;
int idx = getRayIndex( static_cast<LCreal>(Basic::Angle::R2DCC * aoa) );
rays[0][idx] = lim01(rays[0][idx] + signal10);
//if (idx == 0 && getOwnship()->getID() == 1011) {
// std::cout << "sig = " << signal10 << std::endl;
//}
// Send to the track list processor
em->ref(); // ref() for track list processing
rptQueue.put(em);
}
}
// finished
em->unref(); // this unref() undoes the ref() done by RfSystem::rfReceivedEmission
em = 0;
// Get another emission from the queue
lcLock(packetLock);
if (np > 0) {
np--;
em = packets[np];
signal = signals[np];
}
lcUnlock(packetLock);
}
// Transfer the rays
xferRays();
}