Mirror
/
ardupilot
mirror of https://github.com/ArduPilot/ardupilot
5
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
ardupilot/libraries/AP_GPS/GPS_Backend.cpp

306 lines
9.2 KiB
C++
Raw Blame History

/*
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_GPS.h"
#include "GPS_Backend.h"
#include <AP_Logger/AP_Logger.h>
#define GPS_BACKEND_DEBUGGING 0
#if GPS_BACKEND_DEBUGGING
# define Debug(fmt, args ...) do {hal.console->printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); hal.scheduler->delay(1); } while(0)
#else
# define Debug(fmt, args ...)
#endif
#include <GCS_MAVLink/GCS.h>
extern const AP_HAL::HAL& hal;
AP_GPS_Backend::AP_GPS_Backend(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UARTDriver *_port) :
port(_port),
gps(_gps),
state(_state)
{
state.have_speed_accuracy = false;
state.have_horizontal_accuracy = false;
state.have_vertical_accuracy = false;
}
int32_t AP_GPS_Backend::swap_int32(int32_t v) const
{
const uint8_t *b = (const uint8_t *)&v;
union {
int32_t v;
uint8_t b[4];
} u;
u.b[0] = b[3];
u.b[1] = b[2];
u.b[2] = b[1];
u.b[3] = b[0];
return u.v;
}
int16_t AP_GPS_Backend::swap_int16(int16_t v) const
{
const uint8_t *b = (const uint8_t *)&v;
union {
int16_t v;
uint8_t b[2];
} u;
u.b[0] = b[1];
u.b[1] = b[0];
return u.v;
}
/**
fill in time_week_ms and time_week from BCD date and time components
assumes MTK19 millisecond form of bcd_time
*/
void AP_GPS_Backend::make_gps_time(uint32_t bcd_date, uint32_t bcd_milliseconds)
{
uint8_t year, mon, day, hour, min, sec;
uint16_t msec;
year = bcd_date % 100;
mon = (bcd_date / 100) % 100;
day = bcd_date / 10000;
uint32_t v = bcd_milliseconds;
msec = v % 1000; v /= 1000;
sec = v % 100; v /= 100;
min = v % 100; v /= 100;
hour = v % 100;
int8_t rmon = mon - 2;
if (0 >= rmon) {
rmon += 12;
year -= 1;
}
// get time in seconds since unix epoch
uint32_t ret = (year/4) - (GPS_LEAPSECONDS_MILLIS / 1000UL) + 367*rmon/12 + day;
ret += year*365 + 10501;
ret = ret*24 + hour;
ret = ret*60 + min;
ret = ret*60 + sec;
// convert to time since GPS epoch
ret -= 272764785UL;
// get GPS week and time
state.time_week = ret / AP_SEC_PER_WEEK;
state.time_week_ms = (ret % AP_SEC_PER_WEEK) * AP_MSEC_PER_SEC;
state.time_week_ms += msec;
}
/*
fill in 3D velocity for a GPS that doesn't give vertical velocity numbers
*/
void AP_GPS_Backend::fill_3d_velocity(void)
{
float gps_heading = radians(state.ground_course);
state.velocity.x = state.ground_speed * cosf(gps_heading);
state.velocity.y = state.ground_speed * sinf(gps_heading);
state.velocity.z = 0;
state.have_vertical_velocity = false;
}
void
AP_GPS_Backend::inject_data(const uint8_t *data, uint16_t len)
{
// not all backends have valid ports
if (port != nullptr) {
if (port->txspace() > len) {
port->write(data, len);
} else {
Debug("GPS %d: Not enough TXSPACE", state.instance + 1);
}
}
}
void AP_GPS_Backend::_detection_message(char *buffer, const uint8_t buflen) const
{
const uint8_t instance = state.instance;
const struct AP_GPS::detect_state dstate = gps.detect_state[instance];
if (dstate.auto_detected_baud) {
hal.util->snprintf(buffer, buflen,
"GPS %d: detected as %s at %d baud",
instance + 1,
name(),
gps._baudrates[dstate.current_baud]);
} else {
hal.util->snprintf(buffer, buflen,
"GPS %d: specified as %s",
instance + 1,
name());
}
}
void AP_GPS_Backend::broadcast_gps_type() const
{
#ifndef HAL_NO_GCS
char buffer[MAVLINK_MSG_STATUSTEXT_FIELD_TEXT_LEN+1];
_detection_message(buffer, sizeof(buffer));
gcs().send_text(MAV_SEVERITY_INFO, "%s", buffer);
#endif
}
void AP_GPS_Backend::Write_AP_Logger_Log_Startup_messages() const
{
#ifndef HAL_NO_LOGGING
char buffer[MAVLINK_MSG_STATUSTEXT_FIELD_TEXT_LEN+1];
_detection_message(buffer, sizeof(buffer));
AP::logger().Write_Message(buffer);
#endif
}
bool AP_GPS_Backend::should_log() const
{
return gps.should_log();
}
void AP_GPS_Backend::send_mavlink_gps_rtk(mavlink_channel_t chan)
{
#ifndef HAL_NO_GCS
const uint8_t instance = state.instance;
// send status
switch (instance) {
case 0:
mavlink_msg_gps_rtk_send(chan,
0, // Not implemented yet
0, // Not implemented yet
state.rtk_week_number,
state.rtk_time_week_ms,
0, // Not implemented yet
0, // Not implemented yet
state.rtk_num_sats,
state.rtk_baseline_coords_type,
state.rtk_baseline_x_mm,
state.rtk_baseline_y_mm,
state.rtk_baseline_z_mm,
state.rtk_accuracy,
state.rtk_iar_num_hypotheses);
break;
case 1:
mavlink_msg_gps2_rtk_send(chan,
0, // Not implemented yet
0, // Not implemented yet
state.rtk_week_number,
state.rtk_time_week_ms,
0, // Not implemented yet
0, // Not implemented yet
state.rtk_num_sats,
state.rtk_baseline_coords_type,
state.rtk_baseline_x_mm,
state.rtk_baseline_y_mm,
state.rtk_baseline_z_mm,
state.rtk_accuracy,
state.rtk_iar_num_hypotheses);
break;
}
#endif
}
/*
set a timestamp based on arrival time on uart at current byte,
assuming the message started nbytes ago
*/
void AP_GPS_Backend::set_uart_timestamp(uint16_t nbytes)
{
if (port) {
state.uart_timestamp_ms = port->receive_time_constraint_us(nbytes) / 1000U;
}
}
void AP_GPS_Backend::check_new_itow(uint32_t itow, uint32_t msg_length)
{
if (itow != _last_itow) {
_last_itow = itow;
/*
we need to calculate a pseudo-itow, which copes with the
iTow from the GPS changing in unexpected ways. We assume
that timestamps from the GPS are always in multiples of
50ms. That means we can't handle a GPS with an update rate
of more than 20Hz. We could do more, but we'd need the GPS
poll time to be higher
*/
const uint32_t gps_min_period_ms = 50;
// get the time the packet arrived on the UART
uint64_t uart_us = port->receive_time_constraint_us(msg_length);
uint32_t now = AP_HAL::millis();
uint32_t dt_ms = now - _last_ms;
_last_ms = now;
// round to nearest 50ms period
dt_ms = ((dt_ms + (gps_min_period_ms/2)) / gps_min_period_ms) * gps_min_period_ms;
// work out an actual message rate. If we get 5 messages in a
// row with a new rate we switch rate
if (_last_rate_ms == dt_ms) {
if (_rate_counter < 5) {
_rate_counter++;
} else if (_rate_ms != dt_ms) {
_rate_ms = dt_ms;
}
} else {
_rate_counter = 0;
_last_rate_ms = dt_ms;
}
if (_rate_ms == 0) {
// only allow 5Hz to 20Hz in user config
_rate_ms = constrain_int16(gps.get_rate_ms(state.instance), 50, 200);
}
// round to calculated message rate
dt_ms = ((dt_ms + (_rate_ms/2)) / _rate_ms) * _rate_ms;
// calculate pseudo-itow
_pseudo_itow += dt_ms * 1000U;
// use msg arrival time, and correct for jitter
uint64_t local_us = jitter_correction.correct_offboard_timestamp_usec(_pseudo_itow, uart_us);
state.uart_timestamp_ms = local_us / 1000U;
// look for lagged data from the GPS. This is meant to detect
// the case that the GPS is trying to push more data into the
// UART than can fit (eg. with GPS_RAW_DATA at 115200).
float expected_lag;
if (gps.get_lag(state.instance, expected_lag)) {
float lag_s = (now - state.uart_timestamp_ms) * 0.001;
if (lag_s > expected_lag+0.05) {
// more than 50ms over expected lag, increment lag counter
state.lagged_sample_count++;
} else {
state.lagged_sample_count = 0;
}
}
}
}
Reference in New Issue View Git Blame Copy Permalink