mirror of https://github.com/ArduPilot/ardupilot
100 lines
3.7 KiB
C++
100 lines
3.7 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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// GPS proxy driver for APM on PX4 platforms
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//
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// This driver subscribes on PX4s vehicle_gps_position topic and presents the data received to APM.
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// The publisher could be an UAVCAN GNSS module like http://docs.zubax.com/Zubax_GNSS, or any other GNSS
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// hardware supported by the PX4 ecosystem.
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//
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// Code by Holger Steinhaus
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#include <AP_HAL/AP_HAL.h>
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#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
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#include "AP_GPS_PX4.h"
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#include <uORB/uORB.h>
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#include <cmath>
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extern const AP_HAL::HAL& hal;
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AP_GPS_PX4::AP_GPS_PX4(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UARTDriver *_port) :
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AP_GPS_Backend(_gps, _state, _port)
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{
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_gps_sub = orb_subscribe(ORB_ID(vehicle_gps_position));
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}
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AP_GPS_PX4::~AP_GPS_PX4()
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{
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orb_unsubscribe(_gps_sub);
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}
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// update internal state if new GPS information is available
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bool
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AP_GPS_PX4::read(void)
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{
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bool updated = false;
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orb_check(_gps_sub, &updated);
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if (updated) {
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if (OK == orb_copy(ORB_ID(vehicle_gps_position), _gps_sub, &_gps_pos)) {
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state.last_gps_time_ms = AP_HAL::millis();
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state.status = (AP_GPS::GPS_Status) (_gps_pos.fix_type | AP_GPS::NO_FIX);
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state.num_sats = _gps_pos.satellites_used;
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state.hdop = uint16_t(_gps_pos.eph*100.0f + .5f);
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if (_gps_pos.fix_type >= 2) {
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state.location.lat = _gps_pos.lat;
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state.location.lng = _gps_pos.lon;
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state.location.alt = _gps_pos.alt/10;
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state.ground_speed = _gps_pos.vel_m_s;
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state.ground_course = wrap_360(degrees(_gps_pos.cog_rad));
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state.hdop = _gps_pos.eph*100;
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// convert epoch timestamp back to gps epoch - evil hack until we get the genuine
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// raw week information (or APM switches to Posix epoch ;-) )
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const uint64_t posix_offset = 3657ULL * 24 * 3600 * 1000 - GPS_LEAPSECONDS_MILLIS;
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const uint64_t ms_per_week = 7ULL * 24 * 3600 * 1000;
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uint64_t epoch_ms = _gps_pos.time_utc_usec/1000;
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uint64_t gps_ms = epoch_ms - posix_offset;
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state.time_week = (uint16_t)(gps_ms / ms_per_week);
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state.time_week_ms = (uint32_t)(gps_ms - (state.time_week) * ms_per_week);
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if (_gps_pos.time_utc_usec == 0) {
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// This is a work-around for https://github.com/PX4/Firmware/issues/1474
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// reject position reports with invalid time, as APM adjusts it's clock after the first lock has been acquired
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state.status = AP_GPS::NO_FIX;
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}
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}
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if (_gps_pos.fix_type >= 3) {
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state.have_vertical_velocity = _gps_pos.vel_ned_valid;
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state.velocity.x = _gps_pos.vel_n_m_s;
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state.velocity.y = _gps_pos.vel_e_m_s;
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state.velocity.z = _gps_pos.vel_d_m_s;
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state.speed_accuracy = _gps_pos.s_variance_m_s;
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state.have_speed_accuracy = true;
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}
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else {
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state.have_vertical_velocity = false;
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}
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}
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}
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return updated;
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}
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#endif
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