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Fix auto-routing by airways.

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When the from and to points are not on the enroute structure, check the initial and final legs for large turns (more than 90-degrees) from the overall route course. If found, kill the leg, to generate more natural route and avoid very sharp turns in the terminal area.
This commit is contained in:
James Turner 2012-12-30 16:12:11 +00:00
parent 44a44a0246
commit d0e9503766
2 changed files with 45 additions and 8 deletions
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42
src/Navaids/airways.cxx
View file

@ -190,6 +190,13 @@ void Airway::Network::addEdge(int aWay, const SGGeod& aStartPos,
////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////
static double headingDiffDeg(double a, double b)
{
double rawDiff = b - a;
SG_NORMALIZE_RANGE(rawDiff, -180.0, 180.0);
return rawDiff;
}
bool Airway::Network::inNetwork(PositionedID posID) const bool Airway::Network::inNetwork(PositionedID posID) const
{ {
NetworkMembershipDict::iterator it = _inNetworkCache.find(posID); NetworkMembershipDict::iterator it = _inNetworkCache.find(posID);
@ -228,17 +235,44 @@ bool Airway::Network::route(WayptRef aFrom, WayptRef aTo,
return false; return false;
} }
if (exactTo) { return cleanGeneratedPath(aFrom, aTo, aPath, exactTo, exactFrom);
}
bool Airway::Network::cleanGeneratedPath(WayptRef aFrom, WayptRef aTo, WayptVec& aPath,
bool exactTo, bool exactFrom)
{
// path cleaning phase : various cases to handle here.
// if either the TO or FROM waypoints were 'exact', i.e part of the enroute
// structure, we don't want to duplicate them. This happens frequently with
// published SIDs and STARs.
// secondly, if the waypoints are NOT on the enroute structure, the course to
// them may be a significant dog-leg. Check how the leg course deviates
// from the direct course FROM->TO, and delete the first/last leg if it's more
// than 90 degrees out.
// note we delete a maximum of one leg, and no more. This is a heuristic - we
// could check the next (previous) legs, but at some point we'll end up
// deleting too much.
const double MAX_DOG_LEG = 90.0;
double enrouteCourse = SGGeodesy::courseDeg(aFrom->position(), aTo->position()),
finalLegCourse = SGGeodesy::courseDeg(aPath.back()->position(), aTo->position());
bool isDogLeg = fabs(headingDiffDeg(enrouteCourse, finalLegCourse)) > MAX_DOG_LEG;
if (exactTo || isDogLeg) {
aPath.pop_back(); aPath.pop_back();
} }
if (exactFrom) {
// edge case - if from and to are equal, which can happen, don't // edge case - if from and to are equal, which can happen, don't
// crash here. This happens routing EGPH -> EGCC; 'DCS' is common // crash here. This happens routing EGPH -> EGCC; 'DCS' is common
// to the EGPH departure and EGCC STAR. // to the EGPH departure and EGCC STAR.
if (!aPath.empty()) { if (aPath.empty()) {
aPath.erase(aPath.begin()); return true;
} }
double initialLegCourse = SGGeodesy::courseDeg(aFrom->position(), aPath.front()->position());
isDogLeg = fabs(headingDiffDeg(enrouteCourse, initialLegCourse)) > MAX_DOG_LEG;
if (exactFrom || isDogLeg) {
aPath.erase(aPath.begin());
} }
return true; return true;

3
src/Navaids/airways.hxx
View file

@ -71,6 +71,9 @@ public:
int findAirway(const std::string& aName, double aTop, double aBase); int findAirway(const std::string& aName, double aTop, double aBase);
bool cleanGeneratedPath(WayptRef aFrom, WayptRef aTo, WayptVec& aPath,
bool exactTo, bool exactFrom);
bool search2(FGPositionedRef aStart, FGPositionedRef aDest, WayptVec& aRoute); bool search2(FGPositionedRef aStart, FGPositionedRef aDest, WayptVec& aRoute);
/** /**