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Fix surface position calculation.

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Check latitude and local decode is in valid range.
This commit is contained in:
Jon Beniston 2020-11-12 08:40:12 +00:00
parent f823741b34
commit 21956dc9d0
2 changed files with 85 additions and 46 deletions
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80
plugins/channelrx/demodadsb/adsbdemodgui.cpp
View File

@ -474,6 +474,26 @@ void ADSBDemodGUI::updatePosition(Aircraft *aircraft)
m_adsbDemod->setTarget(aircraft->m_azimuth, aircraft->m_elevation);
}
// Called when we have lat & long from local decode and we need to check if it is in a valid range (<180nm/333km)
// or 1/4 of that for surface positions
bool ADSBDemodGUI::updateLocalPosition(Aircraft *aircraft, double latitude, double longitude, bool surfacePosition)
{
// Calculate range to aircraft from station
m_azEl.setTarget(latitude, longitude, feetToMetres(aircraft->m_altitude));
m_azEl.calculate();
// Don't use the full 333km, as there may be some error in station position
if (m_azEl.getDistance() < (surfacePosition ? 80000 : 320000))
{
aircraft->m_latitude = latitude;
aircraft->m_longitude = longitude;
updatePosition(aircraft);
return true;
}
else
return false;
}
// Try to find an airline logo based on ICAO
QIcon *ADSBDemodGUI::getAirlineIcon(const QString &operatorICAO)
{
@ -727,6 +747,7 @@ void ADSBDemodGUI::handleADSB(
m_correlationOnesAvg(correlationOnes);
aircraft->m_rssiItem->setText(QString("%1")
.arg(CalcDb::dbPower(m_correlationOnesAvg.instantAverage()), 3, 'f', 1));
// ADS-B, non-transponder ADS-B or TIS-B rebroadcast of ADS-B (ADS-R)
if ((df == 17) || ((df == 18) && ((ca == 0) || (ca == 1) || (ca == 6))))
{
@ -765,7 +786,8 @@ void ADSBDemodGUI::handleADSB(
}
else if (((tc >= 5) && (tc <= 18)) || ((tc >= 20) && (tc <= 22)))
{
if ((tc >= 5) && (tc <= 8))
bool surfacePosition = (tc >= 5) && (tc <= 8);
if (surfacePosition)
{
// Surface position
@ -879,7 +901,8 @@ void ADSBDemodGUI::handleADSB(
// We also need to check that both frames aren't greater than 10s apart in time (C.2.6.7), otherwise position may be out by ~10deg
// We could compare global + local methods to see if the positions are sensible
if (aircraft->m_cprValid[0] && aircraft->m_cprValid[1]
&& (std::abs(aircraft->m_cprTime[0].toSecsSinceEpoch() - aircraft->m_cprTime[1].toSecsSinceEpoch()) < 10))
&& (std::abs(aircraft->m_cprTime[0].toSecsSinceEpoch() - aircraft->m_cprTime[1].toSecsSinceEpoch()) < 10)
&& !surfacePosition)
{
// Global decode using odd and even frames (C.2.6)
@ -891,21 +914,19 @@ void ADSBDemodGUI::handleADSB(
int ni, m;
int j = std::floor(59.0f*aircraft->m_cprLat[0] - 60.0f*aircraft->m_cprLat[1] + 0.5);
latEven = dLatEven * ((j % 60) + aircraft->m_cprLat[0]);
latEven = dLatEven * (modulus(j, 60) + aircraft->m_cprLat[0]);
// Southern hemisphere is in range 270-360, so adjust to -90-0
if (latEven >= 270.0f)
latEven -= 360.0f;
else if (latEven <= -270.0f)
latEven += 360.0f;
latOdd = dLatOdd * ((j % 59) + aircraft->m_cprLat[1]);
latOdd = dLatOdd * (modulus(j, 59) + aircraft->m_cprLat[1]);
if (latOdd >= 270.0f)
latOdd -= 360.0f;
else if (latOdd <= -270.0f)
latOdd += 360.0f;
if (aircraft->m_cprTime[0] >= aircraft->m_cprTime[1])
latitude = latEven;
else
latitude = latOdd;
if ((latitude <= 90.0) && (latitude >= -90.0))
{
// Check if both frames in same latitude zone
int latEvenNL = cprNL(latEven);
int latOddNL = cprNL(latOdd);
@ -935,40 +956,57 @@ void ADSBDemodGUI::handleADSB(
}
}
else
{
qDebug() << "ADSBDemodGUI::handleADSB: Invalid latitude " << latitude << " for " << hex << aircraft->m_icao
<< " m_cprLat[0] " << aircraft->m_cprLat[0]
<< " m_cprLat[1] " << aircraft->m_cprLat[1];
aircraft->m_cprValid[0] = false;
aircraft->m_cprValid[1] = false;
}
}
else
{
// Local decode using a single aircraft position + location of receiver
// Only valid if within 180nm (C.2.6.4)
// Only valid if airbourne within 180nm/333km (C.2.6.4) or 45nm for surface
// Caclulate latitude
const double dLatEven = 360.0/60.0;
const double dLatOdd = 360.0/59.0;
const double maxDeg = surfacePosition ? 90.0 : 360.0;
const double dLatEven = maxDeg/60.0;
const double dLatOdd = maxDeg/59.0;
double dLat = f ? dLatOdd : dLatEven;
double latitude, longitude;
int j = std::floor(m_azEl.getLocationSpherical().m_latitude/dLat) + std::floor(modulus(m_azEl.getLocationSpherical().m_latitude, dLat)/dLat - aircraft->m_cprLat[f] + 0.5);
aircraft->m_latitude = dLat * (j + aircraft->m_cprLat[f]);
aircraft->m_latitudeItem->setData(Qt::DisplayRole, aircraft->m_latitude);
latitude = dLat * (j + aircraft->m_cprLat[f]);
// Caclulate longitude
double dLong;
int latNL = cprNL(aircraft->m_latitude);
int latNL = cprNL(latitude);
if (f == 0)
{
if (latNL > 0)
dLong = 360.0 / latNL;
dLong = maxDeg / latNL;
else
dLong = 360.0;
dLong = maxDeg;
}
else
{
if ((latNL - 1) > 0)
dLong = 360.0 / (latNL - 1);
dLong = maxDeg / (latNL - 1);
else
dLong = 360.0;
dLong = maxDeg;
}
int m = std::floor(m_azEl.getLocationSpherical().m_longitude/dLong) + std::floor(modulus(m_azEl.getLocationSpherical().m_longitude, dLong)/dLong - aircraft->m_cprLong[f] + 0.5);
aircraft->m_longitude = dLong * (m + aircraft->m_cprLong[f]);
longitude = dLong * (m + aircraft->m_cprLong[f]);
if (updateLocalPosition(aircraft, latitude, longitude, surfacePosition))
{
aircraft->m_latitude = latitude;
aircraft->m_latitudeItem->setData(Qt::DisplayRole, aircraft->m_latitude);
aircraft->m_longitude = longitude;
aircraft->m_longitudeItem->setData(Qt::DisplayRole, aircraft->m_longitude);
aircraft->m_coordinates.push_back(QVariant::fromValue(*new QGeoCoordinate(aircraft->m_latitude, aircraft->m_longitude, aircraft->m_altitude)));
updatePosition(aircraft);
}
}
}
else if (tc == 19)

1
plugins/channelrx/demodadsb/adsbdemodgui.h
View File

@ -497,6 +497,7 @@ private:
void displayStreamIndex();
bool handleMessage(const Message& message);
void updatePosition(Aircraft *aircraft);
bool updateLocalPosition(Aircraft *aircraft, double latitude, double longitude, bool surfacePosition);
void handleADSB(
const QByteArray data,
const QDateTime dateTime,