From: James Turner <jmt@Bishop.local>
Date: Sun, 30 Dec 2012 15:37:25 +0000 (+0000)
Subject: Nicer default SID and approach procedures.
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=44a44a024695f373fe506b655d07f5962a3457b5;p=flightgear.git

Nicer default SID and approach procedures.

Note these are still generic and do NOT take local terrain into account. Don't come crying to me if you fly into nearby terrain because you weren't using a real procedure!
---

diff --git a/src/Autopilot/route_mgr.cxx b/src/Autopilot/route_mgr.cxx
index 5fe1466cb..337f2e9f2 100644
--- a/src/Autopilot/route_mgr.cxx
+++ b/src/Autopilot/route_mgr.cxx
@@ -918,7 +918,14 @@ const char* FGRouteMgr::getSID() const
   return "";
 }
 
-flightgear::SID* createDefaultSID(FGRunway* aRunway)
+static double headingDiffDeg(double a, double b)
+{
+  double rawDiff = b - a;
+  SG_NORMALIZE_RANGE(rawDiff, -180.0, 180.0);
+  return rawDiff;
+}
+
+flightgear::SID* createDefaultSID(FGRunway* aRunway, double enrouteCourse)
 {
   if (!aRunway) {
     return NULL;
@@ -931,22 +938,40 @@ flightgear::SID* createDefaultSID(FGRunway* aRunway)
   
   SGGeod p = aRunway->pointOnCenterline(aRunway->lengthM() + (3.0 * SG_NM_TO_METER));
   WayptRef w = new BasicWaypt(p, ss.str(), NULL);
-  w->setAltitude(runwayElevFt + 2000.0, RESTRICT_AT);
+  w->setAltitude(runwayElevFt + 3000.0, RESTRICT_AT);
   wpts.push_back(w);
   
   ss.str("");
   ss << aRunway->ident() << "-6";
   p = aRunway->pointOnCenterline(aRunway->lengthM() + (6.0 * SG_NM_TO_METER));
   w = new BasicWaypt(p, ss.str(), NULL);
-  w->setAltitude(runwayElevFt + 4000.0, RESTRICT_AT);
-  wpts.push_back(w);
-
-  ss.str("");
-  ss << aRunway->ident() << "-9";
-  p = aRunway->pointOnCenterline(aRunway->lengthM() + (9.0 * SG_NM_TO_METER));
-  w = new BasicWaypt(p, ss.str(), NULL);
   w->setAltitude(runwayElevFt + 6000.0, RESTRICT_AT);
   wpts.push_back(w);
+
+  if (enrouteCourse >= 0.0) {
+    // valid enroute course
+    int index = 3;
+    double course = aRunway->headingDeg();
+    double diff;
+    while (fabs(diff = headingDiffDeg(course, enrouteCourse)) > 45.0) {
+      // turn in the sign of the heading change 45 degrees
+      course += copysign(45.0, diff);
+      ss.str("");
+      ss << "DEP-" << index++;
+      SGGeod pos = wpts.back()->position();
+      pos = SGGeodesy::direct(pos, course, 3.0 * SG_NM_TO_METER);
+      w = new BasicWaypt(pos, ss.str(), NULL);
+      wpts.push_back(w);
+    }
+  } else {
+    // no enroute course, just keep runway heading
+    ss.str("");
+    ss << aRunway->ident() << "-9";
+    p = aRunway->pointOnCenterline(aRunway->lengthM() + (9.0 * SG_NM_TO_METER));
+    w = new BasicWaypt(p, ss.str(), NULL);
+    w->setAltitude(runwayElevFt + 9000.0, RESTRICT_AT);
+    wpts.push_back(w);
+  }
   
   BOOST_FOREACH(Waypt* w, wpts) {
     w->setFlag(WPT_DEPARTURE);
@@ -965,7 +990,12 @@ void FGRouteMgr::setSID(const char* aIdent)
   } 
   
   if (!strcmp(aIdent, "DEFAULT")) {
-    _plan->setSID(createDefaultSID(_plan->departureRunway()));
+    double enrouteCourse = -1.0;
+    if (_plan->destinationAirport()) {
+      enrouteCourse = SGGeodesy::courseDeg(apt->geod(), _plan->destinationAirport()->geod());
+    }
+    
+    _plan->setSID(createDefaultSID(_plan->departureRunway(), enrouteCourse));
     return;
   }
   
@@ -1038,7 +1068,7 @@ const char* FGRouteMgr::getApproach() const
   return "";
 }
 
-flightgear::Approach* createDefaultApproach(FGRunway* aRunway)
+flightgear::Approach* createDefaultApproach(FGRunway* aRunway, double aEnrouteCourse)
 {
   if (!aRunway) {
     return NULL;
@@ -1057,6 +1087,24 @@ flightgear::Approach* createDefaultApproach(FGRunway* aRunway)
   w->setAltitude(thresholdElevFt + 4000, RESTRICT_AT);
   wpts.push_back(w);
 
+// work back form the first point on the centerline
+  
+  if (aEnrouteCourse >= 0.0) {
+    // valid enroute course
+    int index = 4;
+    double course = aRunway->headingDeg();
+    double diff;
+    while (fabs(diff = headingDiffDeg(aEnrouteCourse, course)) > 45.0) {
+      // turn in the sign of the heading change 45 degrees
+      course -= copysign(45.0, diff);
+      ss.str("");
+      ss << "APP-" << index++;
+      SGGeod pos = wpts.front()->position();
+      pos = SGGeodesy::direct(pos, course + 180.0, 3.0 * SG_NM_TO_METER);
+      w = new BasicWaypt(pos, ss.str(), NULL);
+      wpts.insert(wpts.begin(), w);
+    }
+  }
     
   p = aRunway->pointOnCenterline(-8.0 * SG_NM_TO_METER);
   ss.str("");
@@ -1084,7 +1132,12 @@ void FGRouteMgr::setApproach(const char* aIdent)
 {
   FGAirport* apt = _plan->destinationAirport();
   if (!strcmp(aIdent, "DEFAULT")) {
-    _plan->setApproach(createDefaultApproach(_plan->destinationRunway()));
+    double enrouteCourse = -1.0;
+    if (_plan->departureAirport()) {
+      enrouteCourse = SGGeodesy::courseDeg(_plan->departureAirport()->geod(), apt->geod());
+    }
+    
+    _plan->setApproach(createDefaultApproach(_plan->destinationRunway(), enrouteCourse));
     return;
   }