rtl: redability suggestions from review, remove unused subscription

src/modules/navigator/rtl.cpp

@@ -357,12 +357,13 @@ void RTL::setRtlTypeAndDestination()
 		// check the closest allowed destination.
 		findRtlDestination(destination_type, destination, safe_point_index);
 
-		switch (destination_type) {
-		case DestinationType::DESTINATION_TYPE_MISSION_LAND:
+		if (destination_type == DestinationType::DESTINATION_TYPE_MISSION_LAND) {
 			new_rtl_type = RtlType::RTL_DIRECT_MISSION_LAND;
-			break;
 
-		default:
+		} else {
+
+			new_rtl_type = RtlType::RTL_DIRECT;
+
 			land_approaches_s rtl_land_approaches{readVtolLandApproaches(destination)};
 
 			// set loiter position to destination initially, overwrite for VTOL if land approaches exist
@@ -375,10 +376,6 @@ void RTL::setRtlTypeAndDestination()
 			    && rtl_land_approaches.isAnyApproachValid()) {
 				landing_loiter = chooseBestLandingApproach(rtl_land_approaches);
 			}
-
-			new_rtl_type = RtlType::RTL_DIRECT;
-
-			break;
 		}
 	}
 
@@ -406,7 +403,7 @@ PositionYawSetpoint RTL::findClosestSafePoint(float min_dist, uint8_t &safe_poin
 	const bool vtol_in_fw_mode = _vehicle_status_sub.get().is_vtol
 				     && (_vehicle_status_sub.get().vehicle_type == vehicle_status_s::VEHICLE_TYPE_FIXED_WING);
 
-	PositionYawSetpoint safe_point{NAN, NAN, NAN, NAN};
+	PositionYawSetpoint safe_point{(double)NAN, (double)NAN, NAN, NAN};
 
 	if (_safe_points_updated) {
 		_one_rally_point_has_land_approach = false;

src/modules/navigator/rtl.h

@@ -158,7 +158,7 @@ private:
 	 * @brief calculate return altitude from return altitude parameter, current altitude and cone angle
 	 *
 	 * @param[in] rtl_position landing position of the rtl
-	 * param[in] destination_type type of the rtl destination
+	 * @param[in] destination_type type of the rtl destination
 	 * @param[in] cone_half_angle_deg half angle of the cone [deg]
 	 * @return return altitude
 	 */
@@ -229,7 +229,7 @@ private:
 	mutable DatamanCache _dataman_cache_landItem{"rtl_dm_cache_miss_land", 2};
 	uint32_t _mission_id = 0u;
 	uint32_t _safe_points_id = 0u;
-	PositionYawSetpoint _last_position_before_link_loss{NAN, NAN, NAN, NAN};
+	PositionYawSetpoint _last_position_before_link_loss{(double)NAN, (double)NAN, NAN, NAN};
 
 	mission_stats_entry_s _stats;
 

src/modules/navigator/rtl_direct.cpp

@@ -489,7 +489,7 @@ rtl_time_estimate_s RtlDirect::calc_rtl_time_estimate()
 		case RTLState::MOVE_TO_LAND:
 		case RTLState::TRANSITION_TO_MC:
 		case RTLState::MOVE_TO_LAND_HOVER: {
-				// Add cruise segment to home
+				// Add cruise segment to destination
 				float move_to_land_dist{0.f};
 				matrix::Vector2f direction{};
 

src/modules/navigator/rtl_direct.h

@@ -46,7 +46,6 @@
 #include <px4_platform_common/module_params.h>
 #include <uORB/Subscription.hpp>
 #include <uORB/SubscriptionInterval.hpp>
-#include <uORB/topics/home_position.h>
 #include <uORB/topics/navigator_mission_item.h>
 #include <uORB/topics/parameter_update.h>
 #include <uORB/topics/rtl_time_estimate.h>
@@ -167,10 +166,10 @@ private:
 	bool _force_heading{false};
 	RtlTimeEstimator _rtl_time_estimator;
 
-	PositionYawSetpoint _destination{NAN, NAN, NAN, NAN}; ///< the RTL position to fly to
+	PositionYawSetpoint _destination{(double)NAN, (double)NAN, NAN, NAN}; ///< the RTL position to fly to
 	loiter_point_s _land_approach;
 
-	float _rtl_alt{0.0f};	///< AMSL altitude at which the vehicle should return to the home position
+	float _rtl_alt{0.0f}; ///< AMSL altitude at which the vehicle should transit to the destination
 
 	DEFINE_PARAMETERS(
 		(ParamFloat<px4::params::RTL_DESCEND_ALT>) _param_rtl_descend_alt,
@@ -185,7 +184,6 @@ private:
 
 	uORB::SubscriptionInterval _parameter_update_sub{ORB_ID(parameter_update), 1_s};
 	uORB::SubscriptionData<vehicle_global_position_s> _global_pos_sub{ORB_ID(vehicle_global_position)};	/**< global position subscription */
-	uORB::SubscriptionData<home_position_s> _home_pos_sub{ORB_ID(home_position)};		/**< home position subscription */
 	uORB::SubscriptionData<vehicle_land_detected_s> _land_detected_sub{ORB_ID(vehicle_land_detected)};	/**< vehicle land detected subscription */
 	uORB::SubscriptionData<vehicle_status_s> _vehicle_status_sub{ORB_ID(vehicle_status)};	/**< vehicle status subscription */
 	uORB::SubscriptionData<wind_s>		_wind_sub{ORB_ID(wind)};

src/modules/navigator/rtl_mission_fast_reverse.cpp

@@ -258,11 +258,10 @@ void RtlMissionFastReverse::handleLanding(WorkItemType &new_work_item_type)
 			    _work_item_type == WorkItemType::WORK_ITEM_TYPE_MOVE_TO_LAND ||
 			    _work_item_type == WorkItemType::WORK_ITEM_TYPE_MOVE_TO_LAND_AFTER_TRANSITION)) {
 
-			const bool loiter_indefinitely = _param_rtl_land_delay.get() < -FLT_EPSILON;
-
 			_mission_item.lat = _home_pos_sub.get().lat;
 			_mission_item.lon = _home_pos_sub.get().lon;
 			_mission_item.yaw = NAN;
+			_mission_item.altitude = _global_pos_sub.get().alt;
 			_mission_item.altitude_is_relative = false;
 
 			// make previous and next setpoints invalid, such that there will be no line following.
@@ -274,14 +273,17 @@ void RtlMissionFastReverse::handleLanding(WorkItemType &new_work_item_type)
 			    do_need_move_to_item()) {
 				new_work_item_type = WorkItemType::WORK_ITEM_TYPE_MOVE_TO_LAND;
 
-				_mission_item.altitude = _global_pos_sub.get().alt;
 				_mission_item.nav_cmd = NAV_CMD_WAYPOINT;
 				_mission_item.autocontinue = true;
 				_mission_item.time_inside = 0.0f;
 
 			} else {
-				_mission_item.altitude = loiter_indefinitely ? _home_pos_sub.get().alt + _param_rtl_descend_alt.get() : _global_pos_sub.get().alt;
-				_mission_item.nav_cmd = loiter_indefinitely ? NAV_CMD_WAYPOINT : NAV_CMD_LAND;
+				_mission_item.nav_cmd = NAV_CMD_LAND;
+
+				if (_param_rtl_land_delay.get() < -FLT_EPSILON) { // parameter negative -> loiter indefinitely instead of landing
+					_mission_item.altitude = _home_pos_sub.get().alt + _param_rtl_descend_alt.get();
+					_mission_item.nav_cmd = NAV_CMD_WAYPOINT;
+				}
 
 				_mission_item.land_precision = _param_rtl_pld_md.get();