[Gcblue-commits] gcb_wx/src/common simmath.cpp,1.11,1.12

[Dewitt C. <ddc...@us...>]

Update of /cvsroot/gcblue/gcb_wx/src/common
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv28653/src/common

Modified Files:
	simmath.cpp 
Log Message:


Index: simmath.cpp
===================================================================
RCS file: /cvsroot/gcblue/gcb_wx/src/common/simmath.cpp,v
retrieving revision 1.11
retrieving revision 1.12
diff -C2 -d -r1.11 -r1.12
*** simmath.cpp	8 May 2004 21:25:25 -0000	1.11
--- simmath.cpp	19 Jul 2004 00:53:00 -0000	1.12
***************
*** 422,425 ****
--- 422,457 ----
      return tclosest;
  }
+ 
+ /**
+ * Calculates the ground impact point (lon_rad, lat_rad)
+ * assuming constant velocity motion to impact.
+ * This has not been tested.
+ * 
+ * @param terrainHeight_m assumed terrain height in meters
+ * @param lon_rad longitude in radians of impact point
+ * @param lat_rad latitude in radians of impact point
+ * @return time of impact in seconds, negative indicates past
+ */
+ float tcKinematics::CalculateGroundImpactPoint(float terrainHeight_m, 
+ 											   double& lon_rad, double& lat_rad)
+ {
+ 
+     float dz =  terrainHeight_m - mfAlt_m;
+     float v = C_KTSTOMPS*mfSpeed_kts;
+     float vz = v*sinf(mfPitch_rad);
+ 
+ 	float timpact = dz / vz;
+ 
+     float cospitch = cosf(mfPitch_rad);
+ 	float k = C_MTORAD * timpact * v * cospitch;
+     float dlon = k * sinf(mfHeading_rad) / cosf(mfLat_rad);
+     float dlat = k * cosf(mfHeading_rad);
+ 	
+ 	lon_rad = mfLon_rad + dlon;
+ 	lat_rad = mfLat_rad + dlat;
+ 
+     return timpact;
+ }
+ 
  // returns radian heading to track
  float tcKinematics::HeadingToTrack(const tcTrack& track) {