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Simplify beam angle computation

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This commit is contained in:
Tim Schubert 2020-08-28 00:43:47 +02:00
parent 1531696255
commit ae1d24ca80
5 changed files with 43 additions and 168 deletions
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93
model/leo-propagation-loss-model.cc
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@ -21,12 +21,6 @@ LeoPropagationLossModel::GetTypeId (void)
.SetParent<PropagationLossModel> ()
.SetGroupName ("Leo")
.AddConstructor<LeoPropagationLossModel> ()
.AddAttribute ("MaxDistance",
"Cut-off distance for signal propagation",
DoubleValue (2500.0),
MakeDoubleAccessor (&LeoPropagationLossModel::SetCutoffDistance,
&LeoPropagationLossModel::GetCutoffDistance),
MakeDoubleChecker<double> ())
.AddAttribute ("ElevationAngle",
"Cut-off angle for signal propagation",
DoubleValue (40.0),
@ -60,54 +54,45 @@ LeoPropagationLossModel::~LeoPropagationLossModel ()
{
}
double
LeoPropagationLossModel::GetAngle (Ptr<MobilityModel> a, Ptr<MobilityModel> b)
{
Vector3D x = a->GetPosition ();
Vector3D y = b->GetPosition ();
Vector3D pa, pb;
if (x.GetLength () < y.GetLength ())
{
pa = x - y;
pb = y;
NS_LOG_DEBUG ("LEO ground -> space");
}
else
{
pa = y - x;
pb = x;
NS_LOG_DEBUG ("LEO space -> ground");
}
double prod = abs ((pa.x*-pb.x) + (pa.y*-pb.y) + (pa.z*-pb.z));
double norm = pa.GetLength () * pb.GetLength ();
return acos (prod / norm);
}
void
LeoPropagationLossModel::SetElevationAngle (double angle)
{
m_elevationAngle = (90 - angle) * (M_PI/180.0);
m_elevationAngle = angle * (M_PI/180.0);
}
double
LeoPropagationLossModel::GetCutoffDistance (const Ptr<MobilityModel> sat) const
{
double angle = m_elevationAngle;
double hs = sat->GetPosition ().GetLength ();
double a = 1 + tan (angle) * tan (angle);
double b = 2.0 * tan (angle) * hs;
double c = hs*hs - LEO_PROP_EARTH_RAD*LEO_PROP_EARTH_RAD;
double disc = b*b + 4*a*c;
NS_LOG_DEBUG ("angle="<<angle<<" hs="<<hs<<" a="<<a<<" b="<<b<<" c="<<c<<" disc="<<disc);
if (disc < 0)
{
// point not on earth surface
return - 1.0;
}
double t1 = (-b - sqrt (disc)) / (2.0 * a);
double t2 = (-b + sqrt (disc)) / (2.0 * a);
double num1 = Vector2D (t1, - tan (angle) * t1).GetLength ();
double num2 = Vector2D (t2, - tan (angle) * t2).GetLength ();
return fmin (num1, num2);
}
double
LeoPropagationLossModel::GetElevationAngle () const
{
return 90 - (m_elevationAngle * (180.0/M_PI));
}
void
LeoPropagationLossModel::SetCutoffDistance (double d)
{
m_cutoffDistance = d * 1000.0;
}
double
LeoPropagationLossModel::GetCutoffDistance () const
{
return m_cutoffDistance / 1000.0;
return m_elevationAngle * (180.0/M_PI);
}
double
@ -115,27 +100,21 @@ LeoPropagationLossModel::DoCalcRxPower (double txPowerDbm,
Ptr<MobilityModel> a,
Ptr<MobilityModel> b) const
{
Ptr<MobilityModel> sat = a->GetPosition ().GetLength () > b->GetPosition ().GetLength () ? a : b;
double distance = a->GetDistanceFrom (b);
if (distance > m_cutoffDistance)
double cutOff = GetCutoffDistance (sat);
if (distance > cutOff)
{
NS_LOG_DEBUG ("LEO DROP distance: a=" << a->GetPosition () << " b=" << b->GetPosition ()<<" dist=" << distance);
NS_LOG_DEBUG ("LEO DROP distance: a=" << a->GetPosition () << " b=" << b->GetPosition ()<<" dist=" << distance<<" cutoff="<<cutOff);
return -1000.0;
}
double angle = GetAngle (a, b);
if (angle > m_elevationAngle)
{
NS_LOG_DEBUG ("LEO DROP angle: a=" << a->GetPosition () << " b=" << b->GetPosition () << " dist=" << distance << "angle=" << angle);
return -1000.0;
}
// txPowerDbm includes tx antenna gain and losses
// receiver loss and gain added at net device
// P_{RX} = P_{TX} + G_{TX} - L_{TX} - L_{FS} - L_M + G_{RX} - L_{RX}
double rxc = txPowerDbm - m_atmosphericLoss - m_freeSpacePathLoss - m_linkMargin;
NS_LOG_DEBUG ("LEO TRANSMIT: angle=" << angle <<";distance=" << distance << ";rxc=" << rxc);
NS_LOG_DEBUG ("LEO TRANSMIT distance: a=" << a->GetPosition () << " b=" << b->GetPosition ()<<" dist=" << distance <<" cutoff="<<cutOff<< "rxc=" << rxc);
return rxc;
}