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98 lines
3.8 KiB
98 lines
3.8 KiB
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- |
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/* |
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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 <math.h> |
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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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#define MS_PER_WEEK 7*24*3600*1000LL |
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#define DELTA_POSIX_GPS_EPOCH 315964800LL*1000LL |
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#define LEAP_MS_GPS_2014 16*1000LL |
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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 = hal.scheduler->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_cd = wrap_360_cd(degrees(_gps_pos.cog_rad)*100); |
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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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uint64_t epoch_ms = uint64_t(_gps_pos.time_utc_usec/1000.+.5); |
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uint64_t gps_ms = epoch_ms - DELTA_POSIX_GPS_EPOCH + LEAP_MS_GPS_2014; |
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state.time_week = uint16_t(gps_ms / uint64_t(MS_PER_WEEK)); |
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state.time_week_ms = uint32_t(gps_ms - uint64_t(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 aquired |
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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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