Rover: Added reversing loiter_type parameter

APMrover2/Parameters.cpp

@@ -511,7 +511,7 @@ const AP_Param::GroupInfo ParametersG2::var_info[] = {
     // @Param: LOIT_TYPE
     // @DisplayName: Loiter type
     // @Description: Loiter behaviour when moving to the target point
-    // @Values: 0:Forward or reverse to target point,1:Always face bow towards target point
+    // @Values: 0:Forward or reverse to target point,1:Always face bow towards target point,2:Always face stern towards target point
     // @User: Standard
     AP_GROUPINFO("LOIT_TYPE", 25, ParametersG2, loit_type, 0),
 

APMrover2/mode_loiter.cpp

@@ -44,7 +44,7 @@ void ModeLoiter::update()
         _desired_yaw_cd = rover.current_loc.get_bearing_to(_destination);
         float yaw_error_cd = wrap_180_cd(_desired_yaw_cd - ahrs.yaw_sensor);
         // if destination is behind vehicle, reverse towards it
-        if (fabsf(yaw_error_cd) > 9000 && g2.loit_type == 0) {
+        if ((fabsf(yaw_error_cd) > 9000 && g2.loit_type == 0) || g2.loit_type == 2){
             _desired_yaw_cd = wrap_180_cd(_desired_yaw_cd + 18000);
             yaw_error_cd = wrap_180_cd(_desired_yaw_cd - ahrs.yaw_sensor);
             _desired_speed = -_desired_speed;