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Fix retrograd movements and earth rotation

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This commit is contained in:
Tim Schubert 2020-08-18 20:28:50 +02:00
parent b4eb471eb1
commit 166a920fca
4 changed files with 49 additions and 31 deletions
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42
model/leo-circular-orbit-mobility-model.cc
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@ -76,7 +76,6 @@ DotProduct (const Vector3D &l, const Vector3D &r)
double
LeoCircularOrbitMobilityModel::GetSpeed () const
{
// force non-retrograd movement
return sqrt (LEO_EARTH_GM_KM_E10 / m_orbitHeight) * 1e5;
}
@ -91,39 +90,48 @@ LeoCircularOrbitMobilityModel::DoGetVelocity () const
Vector3D
LeoCircularOrbitMobilityModel::PlaneNorm () const
{
int sign = 1;
// ensure correct gradient (not against earth rotation)
if (m_inclination < M_PI/4)
{
sign = -1;
}
return Vector3D (sign * sin (-m_inclination) * cos (m_latitude),
sign * sin (-m_inclination) * sin (m_latitude),
sign * cos (m_inclination));
double lat = CalcLatitude ();
return Vector3D (sin (-m_inclination) * cos (lat),
sin (-m_inclination) * sin (lat),
cos (m_inclination));
}
double
LeoCircularOrbitMobilityModel::GetProgress (Time t) const
{
// TODO use nanos or ms instead? does it give higher precision?
return (2 * M_PI * ((GetSpeed () * t.GetSeconds ()) / LEO_EARTH_RAD_M)) + m_offset;
int sign = 1;
// ensure correct gradient (not against earth rotation)
if (m_inclination > M_PI/2)
{
sign = -1;
}
return sign * (2 * M_PI * ((GetSpeed () * t.GetSeconds ()) / LEO_EARTH_RAD_M)) + m_offset;
}
Vector3D
LeoCircularOrbitMobilityModel::RotatePlane (double a, const Vector3D &x) const
{
Vector3D n = m_plane;
Vector3D n = PlaneNorm ();
return Product (DotProduct (n, x), n)
+ Product (cos (a), CrossProduct (CrossProduct (n, x), n))
+ Product (sin (a), CrossProduct (n, x));
}
double
LeoCircularOrbitMobilityModel::CalcLatitude () const
{
return m_latitude + ((Simulator::Now ().GetDouble () / Hours (24).GetDouble ()) * 2 * M_PI);
}
Vector
LeoCircularOrbitMobilityModel::CalcPosition (Time t) const
{
Vector3D x = Product (m_orbitHeight, Vector3D (cos (m_inclination) * cos (m_latitude),
cos (m_inclination) * sin (m_latitude),
double lat = CalcLatitude ();
// account for orbit latitude and earth rotation offset
Vector3D x = Product (m_orbitHeight, Vector3D (cos (m_inclination) * cos (lat),
cos (m_inclination) * sin (lat),
sin (m_inclination)));
return RotatePlane (GetProgress (t), x);
@ -131,8 +139,6 @@ LeoCircularOrbitMobilityModel::CalcPosition (Time t) const
Vector LeoCircularOrbitMobilityModel::Update ()
{
m_plane = PlaneNorm ();
m_position = CalcPosition (Simulator::Now ());
NotifyCourseChange ();
@ -180,13 +186,13 @@ void LeoCircularOrbitMobilityModel::SetAltitude (double h)
double LeoCircularOrbitMobilityModel::GetInclination () const
{
return (m_inclination / (M_PI)) * 180.0;
return (m_inclination / M_PI) * 180.0;
}
void LeoCircularOrbitMobilityModel::SetInclination (double incl)
{
NS_ASSERT_MSG (incl != 0.0, "Plane must not be orthogonal to axis");
m_inclination = (incl / 180) * M_PI;
m_inclination = (incl / 180.0) * M_PI;
Update ();
}