ardupilot/ArduPlane/adsb.cpp

102 lines
3.7 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
* adsb.cpp
* Copyright (C) Tom Pittenger 2015
*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Plane.h"
/*
* this module deals with ADS-B handling for ArduPlane
* ADS-B is an RF based collision avoidance protocol to tell nearby aircraft your location
* https://en.wikipedia.org/wiki/Automatic_dependent_surveillance_%E2%80%93_broadcast
*
*/
/*
handle periodic adsb database maintenance and handle threats
*/
void Plane::adsb_update(void)
{
adsb.update();
adsb_handle_vehicle_threats();
}
/*
* Handle ADS-B based threats which are platform dependent
*/
void Plane::adsb_handle_vehicle_threats(void)
{
uint32_t now = millis();
AP_ADSB::ADSB_BEHAVIOR behavior = adsb.get_behavior();
switch (control_mode) {
case AUTO:
if (mission.get_current_nav_cmd().id == MAV_CMD_NAV_TAKEOFF) {
// for testing purposes ignore ADS-B traffic until we get into the air so we don't screw up the sim takeoff
break;
}
switch(behavior) {
case AP_ADSB::ADSB_BEHAVIOR_NONE:
default:
break;
case AP_ADSB::ADSB_BEHAVIOR_LOITER:
case AP_ADSB::ADSB_BEHAVIOR_LOITER_AND_DESCEND:
if (adsb.get_another_vehicle_within_radius() && !adsb.get_is_evading_threat()) {
adsb.set_is_evading_threat(true);
gcs_send_text(MAV_SEVERITY_CRITICAL, "ADS-B threat found, performing LOITER");
adsb_state.prev_wp = prev_WP_loc;
set_mode(LOITER);
if (behavior == AP_ADSB::ADSB_BEHAVIOR_LOITER_AND_DESCEND) {
adsb_state.time_last_alt_change_ms = now;
}
}
} // switch behavior
break; // case auto
case LOITER:
switch(behavior) {
case AP_ADSB::ADSB_BEHAVIOR_NONE:
// TODO: recover from this
default:
break;
case AP_ADSB::ADSB_BEHAVIOR_LOITER:
case AP_ADSB::ADSB_BEHAVIOR_LOITER_AND_DESCEND:
if (adsb.get_is_evading_threat()) {
if (!adsb.get_another_vehicle_within_radius()) {
adsb.set_is_evading_threat(false);
gcs_send_text(MAV_SEVERITY_CRITICAL, "ADS-B threat gone, continuing mission");
set_mode(AUTO);
prev_WP_loc = adsb_state.prev_wp;
auto_state.no_crosstrack = false;
} else if (behavior == AP_ADSB::ADSB_BEHAVIOR_LOITER_AND_DESCEND &&
now - adsb_state.time_last_alt_change_ms >= 1000) {
// slowly reduce altitude 1m/s while loitering. Drive into the ground if threat persists
adsb_state.time_last_alt_change_ms = now;
next_WP_loc.alt -= 100;
} // get_another_vehicle_within_radius
} // get_is_evading_threat
} // switch behavior
break; // case LOITER
default:
break;
} // switch control_mode
}