public static double timeOfTargetDistance(Orbit oOrig, Orbit oTgt, double timeStart, double periodtoscan, double numDivisions, out double closestdistance, double targetDistance)
{
double closestApproachTime = timeStart;
double closestApproachDistance = Double.MaxValue;
double minTime = timeStart;
double maxTime = timeStart + periodtoscan;
//work out iterations for precision - we only really need to within a second - so how many iterations do we actually need
//Each iteration gets us 1/10th of the period to scan
for (int iter = 0; iter < 8; iter++)
{
double dt = (maxTime - minTime) / numDivisions;
for (int i = 0; i < numDivisions; i++)
{
double t = minTime + i * dt;
double distance = (getAbsolutePositionAtUT(oOrig, t) - getAbsolutePositionAtUT(oTgt, t)).magnitude;
if (Math.Abs(distance - targetDistance) < closestApproachDistance)
{
closestApproachDistance = Math.Abs(distance - targetDistance);
closestApproachTime = t;
}
}
minTime = KACUtils.Clamp(closestApproachTime - dt, timeStart, timeStart + periodtoscan);
maxTime = KACUtils.Clamp(closestApproachTime + dt, timeStart, timeStart + periodtoscan);
}
closestdistance = closestApproachDistance + targetDistance;
return(closestApproachTime);
}
//enum OrbitAltitudeDirection
//{
// Ascending=1,
// Descending=2
//}
public static double timeOfTargetAltitude(Orbit oOrig, double timeStart, double numDivisions, out double closestdistance, double targetAltitude)
{
double closestApproachTime = timeStart;
double closestApproachAltitude = Double.MaxValue;
double minTime = timeStart;
//work out the end of the period to scan based on whether we are above or below the target altitude
double UTofEndOrbitAltDirection;
double startAltitude = oOrig.getRelativePositionAtUT(timeStart).magnitude - oOrig.referenceBody.Radius;
if (startAltitude < targetAltitude)
{
UTofEndOrbitAltDirection = oOrig.StartUT + oOrig.timeToAp;
}
else
{
UTofEndOrbitAltDirection = oOrig.StartUT + oOrig.timeToPe;
}
double periodtoscan = UTofEndOrbitAltDirection - timeStart;
double maxTime = UTofEndOrbitAltDirection;
//work out iterations for precision - we only really need to within a second - so how many iterations do we actually need
//Each iteration gets us 1/10th of the period to scan
for (int iter = 0; iter < 8; iter++)
{
double dt = (maxTime - minTime) / numDivisions;
for (int i = 0; i < numDivisions; i++)
{
double t = minTime + i * dt;
double distance = oOrig.getRelativePositionAtUT(t).magnitude - oOrig.referenceBody.Radius;
//TODO: NEED TO DO SOMETHING HERE WITH PRECISION!!!! How many decimal place to compare to
//something about = if its not substantially closer, but is substantialy later then ignore it.
//ie if the later crossing is 1meter closer, but its 600 secs later then keep the earlier one
if (Math.Abs(distance - targetAltitude) < closestApproachAltitude)
{
closestApproachAltitude = Math.Abs(distance - targetAltitude);
closestApproachTime = t;
}
}
minTime = KACUtils.Clamp(closestApproachTime - dt, timeStart, timeStart + periodtoscan);
maxTime = KACUtils.Clamp(closestApproachTime + dt, timeStart, timeStart + periodtoscan);
}
closestdistance = closestApproachAltitude + targetAltitude;
return(closestApproachTime);
}