ardupilot/libraries/AP_ADSB/AP_ADSB_uAvionix_MAVLink.cpp

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2020-10-21 15:37:08 -03:00
/*
This program 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 program 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 "AP_ADSB_uAvionix_MAVLink.h"
#if HAL_ADSB_UAVIONIX_MAVLINK_ENABLED
#include <stdio.h> // for sprintf
#include <limits.h>
#include <GCS_MAVLink/GCS.h>
#include <AP_GPS/AP_GPS.h>
#include <AP_Baro/AP_Baro.h>
#include <AP_AHRS/AP_AHRS.h>
#define ADSB_CHAN_TIMEOUT_MS 15000
#define ADSB_BITBASK_RF_CAPABILITIES_UAT_IN (1 << 0)
#define ADSB_BITBASK_RF_CAPABILITIES_1090ES_IN (1 << 1)
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extern const AP_HAL::HAL& hal;
// detect if an port is configured as MAVLink
bool AP_ADSB_uAvionix_MAVLink::detect()
{
// this actually requires SerialProtocol_MAVLink or SerialProtocol_MAVLink2 but
// we can't have a running system with that, so its safe to assume it's already defined
return true;
}
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void AP_ADSB_uAvionix_MAVLink::update()
{
const uint32_t now = AP_HAL::millis();
// send static configuration data to transceiver, every 5s
if (_frontend.out_state.chan_last_ms > 0 && now - _frontend.out_state.chan_last_ms > ADSB_CHAN_TIMEOUT_MS) {
// haven't gotten a heartbeat health status packet in a while, assume hardware failure
// TODO: reset out_state.chan
_frontend.out_state.chan = -1;
gcs().send_text(MAV_SEVERITY_ERROR, "ADSB: Transceiver heartbeat timed out");
} else if (_frontend.out_state.chan >= 0 && !_frontend._my_loc.is_zero() && _frontend.out_state.chan < MAVLINK_COMM_NUM_BUFFERS) {
const mavlink_channel_t chan = (mavlink_channel_t)(MAVLINK_COMM_0 + _frontend.out_state.chan);
if (now - _frontend.out_state.last_config_ms >= 5000 && HAVE_PAYLOAD_SPACE(chan, UAVIONIX_ADSB_OUT_CFG)) {
_frontend.out_state.last_config_ms = now;
send_configure(chan);
} // last_config_ms
// send dynamic data to transceiver at 5Hz
if (now - _frontend.out_state.last_report_ms >= 200 && HAVE_PAYLOAD_SPACE(chan, UAVIONIX_ADSB_OUT_DYNAMIC)) {
_frontend.out_state.last_report_ms = now;
send_dynamic_out(chan);
} // last_report_ms
} // chan_last_ms
}
void AP_ADSB_uAvionix_MAVLink::send_dynamic_out(const mavlink_channel_t chan) const
{
const AP_GPS &gps = AP::gps();
const Vector3f &gps_velocity = gps.velocity();
const int32_t latitude = _frontend._my_loc.lat;
const int32_t longitude = _frontend._my_loc.lng;
const int32_t altGNSS = _frontend._my_loc.alt * 10; // convert cm to mm
const int16_t velVert = gps_velocity.z * 1E2; // convert m/s to cm/s
const int16_t nsVog = gps_velocity.x * 1E2; // convert m/s to cm/s
const int16_t ewVog = gps_velocity.y * 1E2; // convert m/s to cm/s
const uint8_t fixType = gps.status(); // this lines up perfectly with our enum
const uint8_t emStatus = 0; // TODO: implement this ENUM. no emergency = 0
const uint8_t numSats = gps.num_sats();
const uint16_t squawk = _frontend.out_state.cfg.squawk_octal;
uint32_t accHoriz = UINT_MAX;
float accHoriz_f;
if (gps.horizontal_accuracy(accHoriz_f)) {
accHoriz = accHoriz_f * 1E3; // convert m to mm
}
uint16_t accVert = USHRT_MAX;
float accVert_f;
if (gps.vertical_accuracy(accVert_f)) {
accVert = accVert_f * 1E2; // convert m to cm
}
uint16_t accVel = USHRT_MAX;
float accVel_f;
if (gps.speed_accuracy(accVel_f)) {
accVel = accVel_f * 1E3; // convert m/s to mm/s
}
uint16_t state = 0;
if (_frontend.out_state.is_in_auto_mode) {
state |= UAVIONIX_ADSB_OUT_DYNAMIC_STATE_AUTOPILOT_ENABLED;
}
if (!_frontend.out_state.is_flying) {
state |= UAVIONIX_ADSB_OUT_DYNAMIC_STATE_ON_GROUND;
}
// TODO: confirm this sets utcTime correctly
const uint64_t gps_time = gps.time_epoch_usec();
const uint32_t utcTime = gps_time / 1000000ULL;
const AP_Baro &baro = AP::baro();
int32_t altPres = INT_MAX;
if (baro.healthy()) {
// Altitude difference between sea level pressure and current pressure. Result in millimeters
altPres = baro.get_altitude_difference(SSL_AIR_PRESSURE, baro.get_pressure()) * 1E3; // convert m to mm;
}
mavlink_msg_uavionix_adsb_out_dynamic_send(
chan,
utcTime,
latitude,
longitude,
altGNSS,
fixType,
numSats,
altPres,
accHoriz,
accVert,
accVel,
velVert,
nsVog,
ewVog,
emStatus,
state,
squawk);
}
/*
* To expand functionality in their HW, uAvionix has extended a few of the unused MAVLink bits to pack in more new features
* This function will override the MSB byte of the 24bit ICAO address. To ensure an invalid >24bit ICAO is never broadcasted,
* this function is used to create the encoded verison without ever writing to the actual ICAO number. It's created on-demand
*/
uint32_t AP_ADSB_uAvionix_MAVLink::encode_icao(const uint32_t icao_id) const
{
// utilize the upper unused 8bits of the icao with special flags.
// This encoding is required for uAvionix devices that break the MAVLink spec.
// ensure the user assignable icao is 24 bits
uint32_t encoded_icao = icao_id & 0x00FFFFFF;
encoded_icao &= ~0x20000000; // useGnssAltitude should always be FALSE
encoded_icao |= 0x10000000; // csidLogic should always be TRUE
//SIL/SDA are special fields that should be set to 0 with only expert user adjustment
encoded_icao &= ~0x03000000; // SDA should always be FALSE
encoded_icao &= ~0x0C000000; // SIL should always be FALSE
return encoded_icao;
}
/*
* To expand functionality in their HW, uAvionix has extended a few of the unused MAVLink bits to pack in more new features
* This function will override the usually-null ending char of the callsign. It always encodes the last byte [8], even if
* the callsign string is less than 9 chars and there are other zero-padded nulls.
*/
uint8_t AP_ADSB_uAvionix_MAVLink::get_encoded_callsign_null_char()
{
// Encoding of the 8bit null char
// (LSB) - knots
// bit.1 - knots
// bit.2 - knots
// bit.3 - (unused)
// bit.4 - flag - ADSB_BITBASK_RF_CAPABILITIES_1090ES_IN
// bit.5 - flag - ADSB_BITBASK_RF_CAPABILITIES_UAT_IN
// bit.6 - flag - 0 = callsign is treated as callsign, 1 = callsign is treated as flightPlanID/Squawk
// (MSB) - (unused)
uint8_t encoded_null = 0;
if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 0) {
// not set or unknown. no bits set
} else if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 75) {
encoded_null |= 0x01;
} else if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 150) {
encoded_null |= 0x02;
} else if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 300) {
encoded_null |= 0x03;
} else if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 600) {
encoded_null |= 0x04;
} else if (_frontend.out_state.cfg.maxAircraftSpeed_knots <= 1200) {
encoded_null |= 0x05;
} else {
encoded_null |= 0x06;
}
if (_frontend.out_state.cfg.rf_capable & ADSB_BITBASK_RF_CAPABILITIES_1090ES_IN) {
encoded_null |= 0x10;
}
if (_frontend.out_state.cfg.rf_capable & ADSB_BITBASK_RF_CAPABILITIES_UAT_IN) {
encoded_null |= 0x20;
}
/*
If the user has an 8 digit flightPlanID assigned from a filed flight plan, this should be assigned to FlightPlanID, (assigned by remote app)
else if the user has an assigned squawk code from ATC this should be converted from 4 digit octal to 4 character alpha string and assigned to FlightPlanID,
else if a tail number is known it should be set to the tail number of the aircraft, (assigned by remote app)
else it should be left blank (all 0's)
*/
// using the above logic, we must always assign the squawk. once we get configured
// externally then get_encoded_callsign_null_char() stops getting called
snprintf(_frontend.out_state.cfg.callsign, 5, "%04d", unsigned(_frontend.out_state.cfg.squawk_octal) & 0x1FFF);
memset(&_frontend.out_state.cfg.callsign[4], 0, 5); // clear remaining 5 chars
encoded_null |= 0x40;
return encoded_null;
}
/*
* populate and send MAVLINK_MSG_UAVIONIX_ADSB_OUT_CFG
*/
void AP_ADSB_uAvionix_MAVLink::send_configure(const mavlink_channel_t chan)
{
// MAVLink spec says the 9 byte callsign field is 8 byte string with 9th byte as null.
// Here we temporarily set some flags in that null char to signify the callsign
// may be a flightplanID instead
int8_t callsign[sizeof(_frontend.out_state.cfg.callsign)];
uint32_t icao;
memcpy(callsign, _frontend.out_state.cfg.callsign, sizeof(_frontend.out_state.cfg.callsign));
if (_frontend.out_state.cfg.was_set_externally) {
// take values as-is
icao = _frontend.out_state.cfg.ICAO_id;
} else {
callsign[MAVLINK_MSG_UAVIONIX_ADSB_OUT_CFG_FIELD_CALLSIGN_LEN-1] = (int8_t)get_encoded_callsign_null_char();
icao = encode_icao((uint32_t)_frontend.out_state.cfg.ICAO_id);
}
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mavlink_msg_uavionix_adsb_out_cfg_send(
chan,
icao,
(const char*)callsign,
(uint8_t)_frontend.out_state.cfg.emitterType,
(uint8_t)_frontend.out_state.cfg.lengthWidth,
(uint8_t)_frontend.out_state.cfg.gpsOffsetLat,
(uint8_t)_frontend.out_state.cfg.gpsOffsetLon,
_frontend.out_state.cfg.stall_speed_cm,
(uint8_t)_frontend.out_state.cfg.rfSelect);
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}
#endif // HAL_ADSB_ENABLED