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Satellites: Restore shadow circle at arbitrary altitude #3538

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Dec 9, 2023
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Satellites: Restore shadow circle at arbitrary altitude #3538

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0412a9c
Satellites: Restore shadow circle at arbitrary altitude
gzotti Dec 8, 2023
9ca1771
Satellites: remove contradicting shadow enlargement
gzotti Dec 9, 2023
1af4db3
Satellites: Avoid empty info subtitle
gzotti Dec 9, 2023
0df1373
Satellites: SUG updates
gzotti Dec 9, 2023
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77 changes: 74 additions & 3 deletions plugins/Satellites/src/Satellite.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -468,8 +468,10 @@ QString Satellite::getInfoString(const StelCore *core, const InfoStringGroup& fl

QString Satellite::getCommLinkInfo(CommLink comm) const
{
QString commLinkData;
if (status==Satellite::StatusNonoperational)
return QString();

QString commLinkData;
if (!comm.modulation.isEmpty()) // OK, the signal modulation mode is exist
commLinkData = comm.modulation;

Expand Down Expand Up @@ -502,7 +504,6 @@ QString Satellite::getCommLinkInfo(CommLink comm) const
sign='+';

commLinkData.append(QString(": %1 %2 (%3%4 %5)<br />").arg(QString::number(comm.frequency, 'f', 3), qc_("MHz", "frequency"), sign, QString::number(ddop, 'f', 3), qc_("kHz", "frequency")));

return commLinkData;
}

Expand Down Expand Up @@ -827,7 +828,7 @@ void Satellite::update(double)
perigee = pa[0];
apogee = pa[1];
*/
if (height < 100) // below Kármán line: Satellite is certainly lost, at least TLE not applicable.
if (height < 80) // way below Kármán line: Satellite is certainly lost, at least TLE not applicable.
{
// The orbit is no longer valid. Causes include very out of date
// TLE, system date and time out of a reasonable range, and orbital
Expand Down Expand Up @@ -890,6 +891,7 @@ Vec4d Satellite::getUmbraData()
penumbraDistance=rhoE*cos(muP);
// radius of shadow circle
penumbraRadius=rhoE*sin(muP);
//// DBG out
//StelObjectMgr *om=GETSTELMODULE(StelObjectMgr);
//om->setExtraInfoString(StelObject::DebugAid, QString("&rho;<sub>E</sub> %1, r<sub>S</sub> %2, &theta;<sub>E</sub> %3°, &theta;<sub>S</sub> %4° <br/>")
// .arg(QString::number(rhoE, 'f', 3),
Expand Down Expand Up @@ -917,6 +919,75 @@ Vec4d Satellite::getUmbraData()
return Vec4d(umbraDistance, umbraRadius, penumbraDistance, penumbraRadius);
}

//! Get radii and geocentric distances of shadow circles in km for a hypothetical object in dist_km above the (spherical) Earth.
//! Vec4d(umbraDistance, umbraRadius, penumbraDistance, penumbraRadius);
Vec4d Satellite::getUmbraData(double dist_km)
{
static PlanetP earth=GETSTELMODULE(SolarSystem)->getEarth();
static PlanetP sun = GETSTELMODULE(SolarSystem)->getSun();

// Compute altitudes of umbra and penumbra circles. These should show where the satellite enters/exits umbra/penumbra.
// The computation follows ideas from https://celestrak.org/columns/v03n01/
// These sources mention ECI coordinates (Earth Centered Inertial). Presumably TEME (True Equator Mean Equinox) are equivalent, at least for our purposes.
const double rhoE=earth->getEquatorialRadius()*AU+dist_km; // geocentric Satellite distance, km
const double rS=earth->getHeliocentricEclipticPos().norm()*AU; // distance earth...sun
const double thetaE=asin((earth->getEquatorialRadius()*AU)/(rhoE));
// Accurate distance sat...sun from ECI sunpos
//Vec3d sunTEME=pSatWrapper->getSunECIPos() - pSatWrapper->getObserverECIPos(); // km
Vec3d sunEquinoxEqPos = sun->getEquinoxEquatorialPos(StelApp::getInstance().getCore());
Vec3d sunTEME=sunEquinoxEqPos*AU;
const double thetaS=asin((sun->getEquatorialRadius()*AU)/(sunTEME.norm()));
Q_ASSERT(thetaE>thetaS);
const double theta=thetaE-thetaS; // angle so that satellite dives into umbra
// angle at Sun:
const double sigma=asin(sin(theta)*rhoE/rS);
// angle in geocenter
const double eta=M_PI-sigma-theta;
// complement
const double mu=M_PI-eta;
// geocentric distance of shadow circle towards antisun
double umbraDistance=rhoE*cos(mu);
// radius of shadow circle
double umbraRadius=rhoE*sin(mu);
// Repeat for penumbra
const double thetaP=thetaE+thetaS; // angle so that satellite touches penumbra
// angle at Sun:
const double sigmaP=asin(sin(thetaP)*rhoE/rS);
// angle in geocenter
const double etaP=M_PI-sigmaP-thetaP;
// complement
const double muP=M_PI-etaP;
// geocentric distance of shadow circle towards antisun
double penumbraDistance=rhoE*cos(muP);
// radius of shadow circle
double penumbraRadius=rhoE*sin(muP);
//// DBG OUT
//StelObjectMgr *om=GETSTELMODULE(StelObjectMgr);
//om->setExtraInfoString(StelObject::DebugAid, QString("&rho;<sub>E</sub> %1, r<sub>S</sub> %2, &theta;<sub>E</sub> %3°, &theta;<sub>S</sub> %4° <br/>")
// .arg(QString::number(rhoE, 'f', 3),
// QString::number(rS, 'f', 3),
// QString::number(thetaE*M_180_PI, 'f', 3),
// QString::number(thetaS*M_180_PI, 'f', 3)
// )
// );
//om->addToExtraInfoString(StelObject::DebugAid, QString("&theta; %1°, &sigma; %2°, &eta; %3°, &mu; %4° <br/>")
// .arg(
// QString::number(theta*M_180_PI, 'f', 3),
// QString::number(sigma*M_180_PI, 'f', 3),
// QString::number(eta*M_180_PI, 'f', 3),
// QString::number(mu*M_180_PI, 'f', 3)
// )
// );
//om->addToExtraInfoString(StelObject::DebugAid, QString("&theta;<sub>P</sub> %1°, &sigma; %2°, &eta; %3°, &mu; %4° <br/>")
// .arg(
// QString::number(thetaP*M_180_PI, 'f', 3),
// QString::number(sigmaP*M_180_PI, 'f', 3),
// QString::number(etaP*M_180_PI, 'f', 3),
// QString::number(muP*M_180_PI, 'f', 3)
// )
// );
return Vec4d(umbraDistance, umbraRadius, penumbraDistance, penumbraRadius);
}

double Satellite::getDoppler(double freq) const
{
Expand Down
4 changes: 4 additions & 0 deletions plugins/Satellites/src/Satellite.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -249,6 +249,10 @@ class Satellite : public StelObject
//! Vec4d(umbraDistance, umbraRadius, penumbraDistance, penumbraRadius);
Vec4d getUmbraData();

//! Get radii and geocentric distances of shadow circles in km for a hypothetical object in dist_km above the (spherical) Earth.
//! Vec4d(umbraDistance, umbraRadius, penumbraDistance, penumbraRadius);
static Vec4d getUmbraData(double dist_km);

//! Get operational status of satellite
QString getOperationalStatus() const;

Expand Down
102 changes: 42 additions & 60 deletions plugins/Satellites/src/Satellites.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -97,9 +97,9 @@ Satellites::Satellites()
, autoRemoveEnabled(false)
, updateFrequencyHours(0)
, flagUmbraVisible(false)
, flagUmbraAtFixedDistance(false)
, flagUmbraAtFixedAltitude(false)
, umbraColor(1.0f, 0.0f, 0.0f)
, fixedUmbraDistance(1000.0)
, fixedUmbraAltitude(1000.0)
, flagPenumbraVisible(false)
, penumbraColor(1.0f, 0.0f, 0.0f)
, earthShadowEnlargementDanjon(false)
Expand Down Expand Up @@ -689,9 +689,9 @@ void Satellites::restoreDefaultSettings()
conf->setValue("hide_invisible_satellites", false);
conf->setValue("colored_invisible_satellites", true);
conf->setValue("umbra_flag", false);
conf->setValue("umbra_fixed_distance_flag", false);
conf->setValue("umbra_fixed_altitude_flag", false);
conf->setValue("umbra_color", "1.0,0.0,0.0");
conf->setValue("umbra_fixed_distance", 1000.0);
conf->setValue("umbra_fixed_altitude", 1000.0);
conf->setValue("penumbra_flag", false);
conf->setValue("penumbra_color", "1.0,0.0,0.0");
conf->setValue("cf_magnitude_flag", false);
Expand Down Expand Up @@ -834,11 +834,9 @@ void Satellites::loadSettings()

// umbra/penumbra
setFlagUmbraVisible(conf->value("umbra_flag", false).toBool());
// FIXME: Repair the functionality!
setFlagUmbraAtFixedDistance(false);
//setFlagUmbraAtFixedDistance(conf->value("umbra_fixed_distance_flag", false).toBool());
setFlagUmbraAtFixedAltitude(conf->value("umbra_fixed_altitude_flag", false).toBool());
setUmbraColor(Vec3f(conf->value("umbra_color", "1.0,0.0,0.0").toString()));
setUmbraDistance(conf->value("umbra_fixed_distance", 1000.0).toDouble());
setUmbraAltitude(conf->value("umbra_fixed_altitude", 1000.0).toDouble());
setFlagPenumbraVisible(conf->value("penumbra_flag", false).toBool());
setPenumbraColor(Vec3f(conf->value("penumbra_color", "1.0,0.0,0.0").toString()));

Expand Down Expand Up @@ -930,11 +928,9 @@ void Satellites::saveSettingsToConfig()

// umbra/penumbra
conf->setValue("umbra_flag", getFlagUmbraVisible());
// FIXME: Fix and re-enable this function
//conf->setValue("umbra_fixed_distance_flag", getFlagUmbraAtFixedDistance());
conf->setValue("umbra_fixed_distance_flag", false); // Preliminary
conf->setValue("umbra_fixed_altitude_flag", getFlagUmbraAtFixedAltitude());
conf->setValue("umbra_color", getUmbraColor().toStr());
conf->setValue("umbra_fixed_distance", getUmbraDistance());
conf->setValue("umbra_fixed_altitude", getUmbraAltitude());
conf->setValue("penumbra_flag", getFlagPenumbraVisible());
conf->setValue("penumbra_color", getPenumbraColor().toStr());

Expand Down Expand Up @@ -1911,18 +1907,14 @@ void Satellites::setFlagUmbraVisible(bool b)
}
}

void Satellites::setFlagUmbraAtFixedDistance(bool b)
void Satellites::setFlagUmbraAtFixedAltitude(bool b)
{
flagUmbraAtFixedDistance = false;
qDebug() << "setFlagUmbraAtFixedDistance() currently not possible";

// TO BE FIXED
//if (flagUmbraAtFixedDistance != b)
//{
// flagUmbraAtFixedDistance = b;
// emit settingsChanged(); // GZ IS THIS REQUIRED/USEFUL??
// emit flagUmbraAtFixedDistanceChanged(b);
//}
if (flagUmbraAtFixedAltitude != b)
{
flagUmbraAtFixedAltitude = b;
emit settingsChanged(); // GZ IS THIS REQUIRED/USEFUL??
emit flagUmbraAtFixedAltitudeChanged(b);
}
}

void Satellites::setUmbraColor(const Vec3f &c)
Expand All @@ -1931,10 +1923,10 @@ void Satellites::setUmbraColor(const Vec3f &c)
emit umbraColorChanged(c);
}

void Satellites::setUmbraDistance(double d)
void Satellites::setUmbraAltitude(double d)
{
fixedUmbraDistance = d;
emit umbraDistanceChanged(d);
fixedUmbraAltitude = d;
emit umbraAltitudeChanged(d);
}

void Satellites::setFlagPenumbraVisible(bool b)
Expand Down Expand Up @@ -2860,7 +2852,7 @@ void Satellites::drawCircles(StelCore* core, StelPainter &painter)
painter.setLineSmooth(true);
painter.setFont(labelFont);

double lambda, beta, umbraDistance_AU, umbraRadius_AU, penumbraDistance_AU, penumbraRadius_AU;
double lambda, beta;
const Vec3d pos = earth->getEclipticPos();
const Vec3d dir = - sun->getAberrationPush() + pos;
StelUtils::rectToSphe(&lambda, &beta, dir);
Expand All @@ -2871,47 +2863,35 @@ void Satellites::drawCircles(StelCore* core, StelPainter &painter)
if (!newSelected.empty())
sat = getById(newSelected[0].staticCast<Satellite>()->getCatalogNumberString());

if (flagUmbraAtFixedDistance)
Vec4d umbraData;
if (flagUmbraAtFixedAltitude)
{
umbraDistance_AU = penumbraDistance_AU = fixedUmbraDistance/AU+earth->getEquatorialRadius(); // geocentric circle distance [AU]
const double earthDistance=earth->getHeliocentricEclipticPos().norm(); // Earth distance [AU]
const double sunHP = asin(earth->getEquatorialRadius()/earthDistance) * (M_180_PI*3600.); // arcsec.
const double satHP = asin(earth->getEquatorialRadius()/umbraDistance_AU) * (M_180_PI*3600.); // arcsec.
const double sunSD = atan(sun->getEquatorialRadius()/earthDistance) * (M_180_PI*3600.); // arcsec.

//Classical Bessel elements
double f1, f2;
if (earthShadowEnlargementDanjon)
{
static const double danjonScale=1+1./85.-1./594.; // ~1.01, shadow magnification factor (see Espenak 5000 years Canon)
f1=danjonScale*satHP + sunHP + sunSD; // penumbra radius, arcsec
f2=danjonScale*satHP + sunHP - sunSD; // umbra radius, arcsec
}
else
{
const double mHP1=0.998340*satHP;
f1=1.02*(mHP1 + sunHP + sunSD); // penumbra radius, arcsec
f2=1.02*(mHP1 + sunHP - sunSD); // umbra radius, arcsec
}
penumbraRadius_AU=tan(f1/3600.*M_PI_180)*umbraDistance_AU;
umbraRadius_AU=tan(f2/3600.*M_PI_180)*umbraDistance_AU;
umbraData=Satellite::getUmbraData(fixedUmbraAltitude)/AU;
}
else if (!sat.isNull())
{
Vec4d umbraData=sat->getUmbraData();
umbraDistance_AU = umbraData[0]/AU;
umbraRadius_AU = umbraData[1]/AU;
penumbraDistance_AU = umbraData[2]/AU;
penumbraRadius_AU = umbraData[3]/AU;
umbraData=sat->getUmbraData()/AU;
}
else
return;


double shadowScale=1.02;
if (earthShadowEnlargementDanjon)
{
shadowScale = 1.+1./85.-1./594.; // ~1.01, shadow magnification factor (see Espenak 5000 years Canon)
}
// FIXME: Any shadow enlargement here contradicts visibility computations in the main model.
shadowScale = 1.;

const double umbraDistance_AU = umbraData[0];
const double umbraRadius_AU = umbraData[1] * shadowScale;
const double penumbraDistance_AU = umbraData[2];
const double penumbraRadius_AU = umbraData[3] * shadowScale;
StelVertexArray umbra(StelVertexArray::LineLoop);
for (int i=0; i<360; ++i)
for (int i=0; i<4*360; ++i)
{
Vec3d point(umbraDistance_AU, cos(i*M_PI_180)*umbraRadius_AU, sin(i*M_PI_180)*umbraRadius_AU);
Vec3d point(umbraDistance_AU, cos(i*M_PI_180*0.25)*umbraRadius_AU, sin(i*M_PI_180*0.25)*umbraRadius_AU);
rot.transfo(point);
umbra.vertex.append(pos+point);
}
Expand All @@ -2924,16 +2904,18 @@ void Satellites::drawCircles(StelCore* core, StelPainter &painter)
rot.transfo(point);
Vec3d coord = pos+point;
painter.drawSprite2dMode(coord, 5.f);
QString cuLabel = QString("%1 (h=%2 %3)").arg(q_("C.U."), QString::number(AU*(umbraDistance_AU - earth->getEquatorialRadius()), 'f', 1), qc_("km","distance"));
QString number = QString::number( (getFlagUmbraAtFixedAltitude() ? getUmbraAltitude() : sat->latLongSubPointPosition[2] ), 'f', 1);
//QString cuLabel = QString("%1 (h=%2 %3)").arg(q_("C.U."), QString::number(AU*(umbraDistance_AU - earth->getEquatorialRadius()), 'f', 1), qc_("km","distance"));
QString cuLabel = QString("%1 (h=%2 %3)").arg(q_("C.U."), number, qc_("km","distance"));
const float shift = 8.f;
painter.drawText(coord, cuLabel, 0, shift, shift, false);

if (getFlagPenumbraVisible())
{
StelVertexArray penumbra(StelVertexArray::LineLoop);
for (int i=0; i<360; ++i)
for (int i=0; i<4*360; ++i)
{
Vec3d point(penumbraDistance_AU, cos(i*M_PI_180)*penumbraRadius_AU, sin(i*M_PI_180)*penumbraRadius_AU);
Vec3d point(penumbraDistance_AU, cos(i*M_PI_180*0.25)*penumbraRadius_AU, sin(i*M_PI_180*0.25)*penumbraRadius_AU);
rot.transfo(point);
penumbra.vertex.append(pos+point);
}
Expand Down
26 changes: 12 additions & 14 deletions plugins/Satellites/src/Satellites.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -165,8 +165,8 @@ class Satellites : public StelObjectModule
Q_PROPERTY(Vec3f invisibleSatelliteColor READ getInvisibleSatelliteColor WRITE setInvisibleSatelliteColor NOTIFY invisibleSatelliteColorChanged)
Q_PROPERTY(Vec3f transitSatelliteColor READ getTransitSatelliteColor WRITE setTransitSatelliteColor NOTIFY transitSatelliteColorChanged)
Q_PROPERTY(bool flagUmbraVisible READ getFlagUmbraVisible WRITE setFlagUmbraVisible NOTIFY flagUmbraVisibleChanged)
Q_PROPERTY(bool flagUmbraAtFixedDistance READ getFlagUmbraAtFixedDistance WRITE setFlagUmbraAtFixedDistance NOTIFY flagUmbraAtFixedDistanceChanged)
Q_PROPERTY(double umbraDistance READ getUmbraDistance WRITE setUmbraDistance NOTIFY umbraDistanceChanged)
Q_PROPERTY(bool flagUmbraAtFixedAltitude READ getFlagUmbraAtFixedAltitude WRITE setFlagUmbraAtFixedAltitude NOTIFY flagUmbraAtFixedAltitudeChanged)
Q_PROPERTY(double umbraAltitude READ getUmbraAltitude WRITE setUmbraAltitude NOTIFY umbraAltitudeChanged)
Q_PROPERTY(Vec3f umbraColor READ getUmbraColor WRITE setUmbraColor NOTIFY umbraColorChanged)
Q_PROPERTY(bool flagPenumbraVisible READ getFlagPenumbraVisible WRITE setFlagPenumbraVisible NOTIFY flagPenumbraVisibleChanged)
Q_PROPERTY(Vec3f penumbraColor READ getPenumbraColor WRITE setPenumbraColor NOTIFY penumbraColorChanged)
Expand Down Expand Up @@ -435,9 +435,9 @@ class Satellites : public StelObjectModule
void invisibleSatelliteColorChanged(Vec3f);
void transitSatelliteColorChanged(Vec3f);
void flagUmbraVisibleChanged(bool b);
void flagUmbraAtFixedDistanceChanged(bool b);
void flagUmbraAtFixedAltitudeChanged(bool b);
void umbraColorChanged(Vec3f);
void umbraDistanceChanged(double d);
void umbraAltitudeChanged(double d);
void flagPenumbraVisibleChanged(bool b);
void penumbraColorChanged(Vec3f);
void flagCFKnownStdMagnitudeChanged(bool b);
Expand Down Expand Up @@ -611,11 +611,10 @@ public slots:
void setFlagUmbraVisible(bool b);
bool getFlagUmbraVisible() { return flagUmbraVisible; }

//! Set whether ring of Earth's umbra should be displayed at fixed distance.
//! Set whether ring of Earth's umbra should be displayed at given satellite altitude.
//! Emits settingsChanged() if the value changes.
//! V23.1: For now this had to be disabled/set to false.
void setFlagUmbraAtFixedDistance(bool b);
bool getFlagUmbraAtFixedDistance() { return flagUmbraAtFixedDistance; }
void setFlagUmbraAtFixedAltitude(bool b);
bool getFlagUmbraAtFixedAltitude() { return flagUmbraAtFixedAltitude; }

//! Get color for ring of Earth's umbra
//! @return color
Expand All @@ -625,9 +624,9 @@ public slots:

//! Get the fixed distance for center of visualized Earth's umbra
//! @return distance, km
double getUmbraDistance() { return fixedUmbraDistance; }
double getUmbraAltitude() { return fixedUmbraAltitude; }
//! Set the fixed distance for center of visualized Earth's umbra
void setUmbraDistance(double d);
void setUmbraAltitude(double d);

//! Set whether ring of Earth's penumbra should be displayed.
//! Emits settingsChanged() if the value changes.
Expand Down Expand Up @@ -916,12 +915,11 @@ private slots:
//@{
//! Flag enabling visualization the Earth's umbra.
bool flagUmbraVisible;
//! Flag enabling visualization the Earth's umbra at fixed distance
//! V23.1: This had to be disabled until computation will be implemented correctly.
bool flagUmbraAtFixedDistance; // MUST REMAIN false FOR NOW!
//! Flag enabling visualization the Earth's umbra at a given altitude above a spherical Earth
bool flagUmbraAtFixedAltitude;
Vec3f umbraColor;
//! The distance for center of visualized Earth's umbra in kilometers
double fixedUmbraDistance;
double fixedUmbraAltitude;
//! Flag enabling visualization the Earth's penumbra.
bool flagPenumbraVisible;
Vec3f penumbraColor;
Expand Down
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