AC_PrecLand: rotate target vector based on sensor orient

Since, the frontend takes care of rotating sensor frame target vector to body frame, the  sitl backend should return unit
vector in sensor frame instead of body frame. This is to have homogeneity among backends.

libraries/AC_PrecLand/AC_PrecLand_SITL.cpp

@@ -21,6 +21,15 @@ void AC_PrecLand_SITL::update()
         _los_meas_body =  body_to_ned.mul_transpose(-position).tofloat();
         _distance_to_target = _sitl->precland_sim.option_enabled(SITL::SIM_Precland::Option::ENABLE_TARGET_DISTANCE) ? _los_meas_body.length() : 0.0f;
         _los_meas_body /= _los_meas_body.length();
+
+        if (_frontend._orient != Rotation::ROTATION_PITCH_270) {
+            // rotate body frame vector based on orientation
+            // this is done to have homogeneity among backends
+            // frontend rotates it back to get correct body frame vector
+            _los_meas_body.rotate_inverse(_frontend._orient);
+            _los_meas_body.rotate_inverse(ROTATION_PITCH_90);
+        }
+
         _have_los_meas = true;
         _los_meas_time_ms = _sitl->precland_sim.last_update_ms();
     } else {