added comment

paparazzi · Feb 19, 2011 · c54e783 · c54e783
1 parent 9a8170b
commit c54e783
Showing 1 changed file with 1 addition and 4 deletions.
diff --git a/sw/airborne/math/pprz_geodetic_int.c b/sw/airborne/math/pprz_geodetic_int.c
@@ -53,7 +53,7 @@ void ltp_def_from_ecef_i(struct LtpDef_i* def, struct EcefCoor_i* ecef) {
 
   def->ltp_of_ecef.m[0] = -sin_lon;
   def->ltp_of_ecef.m[1] =  cos_lon;
-  def->ltp_of_ecef.m[2] =  0;
+  def->ltp_of_ecef.m[2] =  0; /* this element is always zero http://en.wikipedia.org/wiki/Geodetic_system#From_ECEF_to_ENU */
   def->ltp_of_ecef.m[3] = (int32_t)((-(int64_t)sin_lat*(int64_t)cos_lon)>>HIGH_RES_TRIG_FRAC);
   def->ltp_of_ecef.m[4] = (int32_t)((-(int64_t)sin_lat*(int64_t)sin_lon)>>HIGH_RES_TRIG_FRAC);
   def->ltp_of_ecef.m[5] =  cos_lat;
@@ -64,9 +64,6 @@ void ltp_def_from_ecef_i(struct LtpDef_i* def, struct EcefCoor_i* ecef) {
 }
 
 
-//void init_ltp_from_lla_i(struct LtpRef_i* ref_param, struct LlaCoor_i* ref_pos) {
-//}
-
 void enu_of_ecef_point_i(struct EnuCoor_i* enu, struct LtpDef_i* def, struct EcefCoor_i* ecef) {
 
   struct EcefCoor_i delta;