rtl.h

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/**
 * @file rtl.h
 *
 * Helper class for RTL
 *
 * @author Julian Oes <julian@oes.ch>
 * @author Anton Babushkin <anton.babushkin@me.com>
 */

#pragma once

#include <px4_platform_common/module_params.h>

#include "navigator_mode.h"
#include "mission_block.h"

#include <uORB/topics/home_position.h>

class Navigator;

class RTL : public MissionBlock, public ModuleParams
{
public:
    enum RTLType {
        RTL_HOME = 0,
        RTL_LAND,
        RTL_MISSION,
        RTL_CLOSEST,
    };

    enum RTLDestinationType {
        RTL_DESTINATION_HOME = 0,
        RTL_DESTINATION_MISSION_LANDING,
        RTL_DESTINATION_SAFE_POINT,
    };

    RTL(Navigator *navigator);

    ~RTL() = default;

    void on_inactive() override;
    void on_activation() override;
    void on_active() override;

    void find_RTL_destination();

    void set_return_alt_min(bool min);

    int rtl_type() const;

    int rtl_destination();

private:
    /**
     * Set the RTL item
     */
    void        set_rtl_item();

    /**
     * Move to next RTL item
     */
    void        advance_rtl();


    float calculate_return_alt_from_cone_half_angle(float cone_half_angle_deg);

    enum RTLState {
        RTL_STATE_NONE = 0,
        RTL_STATE_CLIMB,
        RTL_STATE_RETURN,
        RTL_STATE_TRANSITION_TO_MC,
        RTL_STATE_DESCEND,
        RTL_STATE_LOITER,
        RTL_STATE_LAND,
        RTL_STATE_LANDED,
    } _rtl_state{RTL_STATE_NONE};

    struct RTLPosition {
        double lat;
        double lon;
        float alt;
        float yaw;
        uint8_t safe_point_index; ///< 0 = home position, 1 = mission landing, >1 = safe landing points (rally points)
        RTLDestinationType type{RTL_DESTINATION_HOME};

        void set(const home_position_s &home_position)
        {
            lat = home_position.lat;
            lon = home_position.lon;
            alt = home_position.alt;
            yaw = home_position.yaw;
            safe_point_index = 0;
            type = RTL_DESTINATION_HOME;
        }
    };

    RTLPosition _destination{}; ///< the RTL position to fly to (typically the home position or a safe point)

    float _rtl_alt{0.0f};   // AMSL altitude at which the vehicle should return to the home position
    bool _rtl_alt_min{false};

    DEFINE_PARAMETERS(
        (ParamFloat<px4::params::RTL_RETURN_ALT>) _param_rtl_return_alt,
        (ParamFloat<px4::params::RTL_DESCEND_ALT>) _param_rtl_descend_alt,
        (ParamFloat<px4::params::RTL_LAND_DELAY>) _param_rtl_land_delay,
        (ParamFloat<px4::params::RTL_MIN_DIST>) _param_rtl_min_dist,
        (ParamInt<px4::params::RTL_TYPE>) _param_rtl_type,
        (ParamInt<px4::params::RTL_CONE_ANG>) _param_rtl_cone_half_angle_deg
    )
};