/****************************************************************************
*
* Copyright (C) 2013, 2014 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file position_estimator_inav_main.c
* Model-identification based position estimator for multirotors
*
* @author Anton Babushkin <anton.babushkin@me.com>
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <fcntl.h>
#include <string.h>
#include <nuttx/config.h>
#include <nuttx/sched.h>
#include <sys/prctl.h>
#include <termios.h>
#include <math.h>
#include <float.h>
#include <uORB/uORB.h>
#include <uORB/topics/parameter_update.h>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/actuator_armed.h>
#include <uORB/topics/sensor_combined.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_global_position.h>
#include <uORB/topics/vehicle_gps_position.h>
#include <uORB/topics/vision_position_estimate.h>
#include <uORB/topics/home_position.h>
#include <uORB/topics/optical_flow.h>
#include <mavlink/mavlink_log.h>
#include <poll.h>
#include <systemlib/err.h>
#include <geo/geo.h>
#include <systemlib/systemlib.h>
#include <drivers/drv_hrt.h>
#include "position_estimator_inav_params.h"
#include "inertial_filter.h"
#define MIN_VALID_W 0.00001f
#define PUB_INTERVAL 10000 // limit publish rate to 100 Hz
#define EST_BUF_SIZE 250000 / PUB_INTERVAL // buffer size is 0.5s
static bool thread_should_exit = false; /**< Deamon exit flag */
static bool thread_running = false; /**< Deamon status flag */
static int position_estimator_inav_task; /**< Handle of deamon task / thread */
static bool verbose_mode = false;
static const hrt_abstime vision_topic_timeout = 500000; // Vision topic timeout = 0.5s
static const hrt_abstime gps_topic_timeout = 500000; // GPS topic timeout = 0.5s
static const hrt_abstime flow_topic_timeout = 1000000; // optical flow topic timeout = 1s
static const hrt_abstime sonar_timeout = 150000; // sonar timeout = 150ms
static const hrt_abstime sonar_valid_timeout = 1000000; // estimate sonar distance during this time after sonar loss
static const hrt_abstime xy_src_timeout = 2000000; // estimate position during this time after position sources loss
static const uint32_t updates_counter_len = 1000000;
static const float max_flow = 1.0f; // max flow value that can be used, rad/s
__EXPORT int position_estimator_inav_main(int argc, char *argv[]);
int position_estimator_inav_thread_main(int argc, char *argv[]);
static void usage(const char *reason);
static inline int min(int val1, int val2)
{
return (val1 < val2) ? val1 : val2;
}
static inline int max(int val1, int val2)
{
return (val1 > val2) ? val1 : val2;
}
/**
* Print the correct usage.
*/
static void usage(const char *reason)
{
if (reason) {
fprintf(stderr, "%s\n", reason);
}
fprintf(stderr, "usage: position_estimator_inav {start|stop|status} [-v]\n\n");
exit(1);
}
/**
* The position_estimator_inav_thread only briefly exists to start
* the background job. The stack size assigned in the
* Makefile does only apply to this management task.
*
* The actual stack size should be set in the call
* to task_create().
*/
int position_estimator_inav_main(int argc, char *argv[])
{
if (argc < 1) {
usage("missing command");
}
if (!strcmp(argv[1], "start")) {
if (thread_running) {
warnx("already running");
/* this is not an error */
exit(0);
}
verbose_mode = false;
if (argc > 1)
if (!strcmp(argv[2], "-v")) {
verbose_mode = true;
}
thread_should_exit = false;
position_estimator_inav_task = task_spawn_cmd("position_estimator_inav",
SCHED_DEFAULT, SCHED_PRIORITY_MAX - 5, 5000,
position_estimator_inav_thread_main,
(argv) ? (const char **) &argv[2] : (const char **) NULL);
exit(0);
}
if (!strcmp(argv[1], "stop")) {
if (thread_running) {
warnx("stop");
thread_should_exit = true;
} else {
warnx("app not started");
}
exit(0);
}
if (!strcmp(argv[1], "status")) {
if (thread_running) {
warnx("app is running");
} else {
warnx("app not started");
}
exit(0);
}
usage("unrecognized command");
exit(1);
}
static void write_debug_log(const char *msg, float dt, float x_est[2], float y_est[2], float z_est[2], float x_est_prev[2], float y_est_prev[2], float z_est_prev[2], float acc[3], float corr_gps[3][2], float w_xy_gps_p, float w_xy_gps_v)
{
FILE *f = fopen("/fs/microsd/inav.log", "a");
if (f) {
char *s = malloc(256);
unsigned n = snprintf(s, 256, "%llu %s\n\tdt=%.5f x_est=[%.5f %.5f] y_est=[%.5f %.5f] z_est=[%.5f %.5f] x_est_prev=[%.5f %.5f] y_est_prev=[%.5f %.5f] z_est_prev=[%.5f %.5f]\n",
hrt_absolute_time(), msg, (double)dt,
(double)x_est[0], (double)x_est[1], (double)y_est[0], (double)y_est[1], (double)z_est[0], (double)z_est[1],
(double)x_est_prev[0], (double)x_est_prev[1], (double)y_est_prev[0], (double)y_est_prev[1], (double)z_est_prev[0], (double)z_est_prev[1]);
fwrite(s, 1, n, f);
n = snprintf(s, 256, "\tacc=[%.5f %.5f %.5f] gps_pos_corr=[%.5f %.5f %.5f] gps_vel_corr=[%.5f %.5f %.5f] w_xy_gps_p=%.5f w_xy_gps_v=%.5f\n",
(double)acc[0], (double)acc[1], (double)acc[2],
(double)corr_gps[0][0], (double)corr_gps[1][0], (double)corr_gps[2][0], (double)corr_gps[0][1], (double)corr_gps[1][1], (double)corr_gps[2][1],
(double)w_xy_gps_p, (double)w_xy_gps_v);
fwrite(s, 1, n, f);
free(s);
}
fsync(fileno(f));
fclose(f);
}
/****************************************************************************
* main
****************************************************************************/
int position_estimator_inav_thread_main(int argc, char *argv[])
{
warnx("started");
int mavlink_fd;
mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
mavlink_log_info(mavlink_fd, "[inav] started");
float x_est[2] = { 0.0f, 0.0f }; // pos, vel
float y_est[2] = { 0.0f, 0.0f }; // pos, vel
float z_est[2] = { 0.0f, 0.0f }; // pos, vel
float est_buf[EST_BUF_SIZE][3][2]; // estimated position buffer
float R_buf[EST_BUF_SIZE][3][3]; // rotation matrix buffer
float R_gps[3][3]; // rotation matrix for GPS correction moment
memset(est_buf, 0, sizeof(est_buf));
memset(R_buf, 0, sizeof(R_buf));
memset(R_gps, 0, sizeof(R_gps));
int buf_ptr = 0;
static const float min_eph_epv = 2.0f; // min EPH/EPV, used for weight calculation
static const float max_eph_epv = 20.0f; // max EPH/EPV acceptable for estimation
float eph = max_eph_epv;
float epv = 1.0f;
float eph_flow = 1.0f;
float eph_vision = 0.5f;
float epv_vision = 0.5f;
float x_est_prev[2], y_est_prev[2], z_est_prev[2];
memset(x_est_prev, 0, sizeof(x_est_prev));
memset(y_est_prev, 0, sizeof(y_est_prev));
memset(z_est_prev, 0, sizeof(z_est_prev));
int baro_init_cnt = 0;
int baro_init_num = 200;
float baro_offset = 0.0f; // baro offset for reference altitude, initialized on start, then adjusted
float surface_offset = 0.0f; // ground level offset from reference altitude
float surface_offset_rate = 0.0f; // surface offset change rate
float alt_avg = 0.0f;
bool landed = true;
hrt_abstime landed_time = 0;
hrt_abstime accel_timestamp = 0;
hrt_abstime baro_timestamp = 0;
bool ref_inited = false;
hrt_abstime ref_init_start = 0;
const hrt_abstime ref_init_delay = 1000000; // wait for 1s after 3D fix
struct map_projection_reference_s ref;
memset(&ref, 0, sizeof(ref));
hrt_abstime home_timestamp = 0;
uint16_t accel_updates = 0;
uint16_t baro_updates = 0;
uint16_t gps_updates = 0;
uint16_t attitude_updates = 0;
uint16_t flow_updates = 0;
hrt_abstime updates_counter_start = hrt_absolute_time();
hrt_abstime pub_last = hrt_absolute_time();
hrt_abstime t_prev = 0;
/* store error when sensor updates, but correct on each time step to avoid jumps in estimated value */
float acc[] = { 0.0f, 0.0f, 0.0f }; // N E D
float acc_bias[] = { 0.0f, 0.0f, 0.0f }; // body frame
float corr_baro = 0.0f; // D
float corr_gps[3][2] = {
{ 0.0f, 0.0f }, // N (pos, vel)
{ 0.0f, 0.0f }, // E (pos, vel)
{ 0.0f, 0.0f }, // D (pos, vel)
};
float w_gps_xy = 1.0f;
float w_gps_z = 1.0f;
float corr_vision[3][2] = {
{ 0.0f, 0.0f }, // N (pos, vel)
{ 0.0f, 0.0f }, // E (pos, vel)
{ 0.0f, 0.0f }, // D (pos, vel)
};
float corr_sonar = 0.0f;
float corr_sonar_filtered = 0.0f;
float corr_flow[] = { 0.0f, 0.0f }; // N E
float w_flow = 0.0f;
float sonar_prev = 0.0f;
hrt_abstime flow_prev = 0; // time of last flow measurement
hrt_abstime sonar_time = 0; // time of last sonar measurement (not filtered)
hrt_abstime sonar_valid_time = 0; // time of last sonar measurement used for correction (filtered)
bool gps_valid = false; // GPS is valid
bool sonar_valid = false; // sonar is valid
bool flow_valid = false; // flow is valid
bool flow_accurate = false; // flow should be accurate (this flag not updated if flow_valid == false)
bool vision_valid = false;
/* declare and safely initialize all structs */
struct actuator_controls_s actuator;
memset(&actuator, 0, sizeof(actuator));
struct actuator_armed_s armed;
memset(&armed, 0, sizeof(armed));
struct sensor_combined_s sensor;
memset(&sensor, 0, sizeof(sensor));
struct vehicle_gps_position_s gps;
memset(&gps, 0, sizeof(gps));
struct home_position_s home;
memset(&home, 0, sizeof(home));
struct vehicle_attitude_s att;
memset(&att, 0, sizeof(att));
struct vehicle_local_position_s local_pos;
memset(&local_pos, 0, sizeof(local_pos));
struct optical_flow_s flow;
memset(&flow, 0, sizeof(flow));
struct vision_position_estimate vision;
memset(&vision, 0, sizeof(vision));
struct vehicle_global_position_s global_pos;
memset(&global_pos, 0, sizeof(global_pos));
/* subscribe */
int parameter_update_sub = orb_subscribe(ORB_ID(parameter_update));
int actuator_sub = orb_subscribe(ORB_ID_VEHICLE_ATTITUDE_CONTROLS);
int armed_sub = orb_subscribe(ORB_ID(actuator_armed));
int sensor_combined_sub = orb_subscribe(ORB_ID(sensor_combined));
int vehicle_attitude_sub = orb_subscribe(ORB_ID(vehicle_attitude));
int optical_flow_sub = orb_subscribe(ORB_ID(optical_flow));
int vehicle_gps_position_sub = orb_subscribe(ORB_ID(vehicle_gps_position));
int vision_position_estimate_sub = orb_subscribe(ORB_ID(vision_position_estimate));
int home_position_sub = orb_subscribe(ORB_ID(home_position));
/* advertise */
orb_advert_t vehicle_local_position_pub = orb_advertise(ORB_ID(vehicle_local_position), &local_pos);
orb_advert_t vehicle_global_position_pub = -1;
struct position_estimator_inav_params params;
struct position_estimator_inav_param_handles pos_inav_param_handles;
/* initialize parameter handles */
parameters_init(&pos_inav_param_handles);
/* first parameters read at start up */
struct parameter_update_s param_update;
orb_copy(ORB_ID(parameter_update), parameter_update_sub, ¶m_update); /* read from param topic to clear updated flag */
/* first parameters update */
parameters_update(&pos_inav_param_handles, ¶ms);
struct pollfd fds_init[1] = {
{ .fd = sensor_combined_sub, .events = POLLIN },
};
/* wait for initial baro value */
bool wait_baro = true;
thread_running = true;
while (wait_baro && !thread_should_exit) {
int ret = poll(fds_init, 1, 1000);
if (ret < 0) {
/* poll error */
mavlink_log_info(mavlink_fd, "[inav] poll error on init");
} else if (ret > 0) {
if (fds_init[0].revents & POLLIN) {
orb_copy(ORB_ID(sensor_combined), sensor_combined_sub, &sensor);
if (wait_baro && sensor.baro_timestamp != baro_timestamp) {
baro_timestamp = sensor.baro_timestamp;
/* mean calculation over several measurements */
if (baro_init_cnt < baro_init_num) {
if (isfinite(sensor.baro_alt_meter)) {
baro_offset += sensor.baro_alt_meter;
baro_init_cnt++;
}
} else {
wait_baro = false;
baro_offset /= (float) baro_init_cnt;
warnx("baro offs: %.2f", (double)baro_offset);
mavlink_log_info(mavlink_fd, "[inav] baro offs: %.2f", (double)baro_offset);
local_pos.z_valid = true;
local_pos.v_z_valid = true;
}
}
}
}
}
/* main loop */
struct pollfd fds[1] = {
{ .fd = vehicle_attitude_sub, .events = POLLIN },
};
while (!thread_should_exit) {
int ret = poll(fds, 1, 20); // wait maximal 20 ms = 50 Hz minimum rate
hrt_abstime t = hrt_absolute_time();
if (ret < 0) {
/* poll error */
mavlink_log_info(mavlink_fd, "[inav] poll error on init");
continue;
} else if (ret > 0) {
/* act on attitude updates */
/* vehicle attitude */
orb_copy(ORB_ID(vehicle_attitude), vehicle_attitude_sub, &att);
attitude_updates++;
bool updated;
/* parameter update */
orb_check(parameter_update_sub, &updated);
if (updated) {
struct parameter_update_s update;
orb_copy(ORB_ID(parameter_update), parameter_update_sub, &update);
parameters_update(&pos_inav_param_handles, ¶ms);
}
/* actuator */
orb_check(actuator_sub, &updated);
if (updated) {
orb_copy(ORB_ID_VEHICLE_ATTITUDE_CONTROLS, actuator_sub, &actuator);
}
/* armed */
orb_check(armed_sub, &updated);
if (updated) {
orb_copy(ORB_ID(actuator_armed), armed_sub, &armed);
}
/* sensor combined */
orb_check(sensor_combined_sub, &updated);
if (updated) {
orb_copy(ORB_ID(sensor_combined), sensor_combined_sub, &sensor);
if (sensor.accelerometer_timestamp != accel_timestamp) {
if (att.R_valid) {
/* correct accel bias */
sensor.accelerometer_m_s2[0] -= acc_bias[0];
sensor.accelerometer_m_s2[1] -= acc_bias[1];
sensor.accelerometer_m_s2[2] -= acc_bias[2];
/* transform acceleration vector from body frame to NED frame */
for (int i = 0; i < 3; i++) {
acc[i] = 0.0f;
for (int j = 0; j < 3; j++) {
acc[i] += att.R[i][j] * sensor.accelerometer_m_s2[j];
}
}
acc[2] += CONSTANTS_ONE_G;
} else {
memset(acc, 0, sizeof(acc));
}
accel_timestamp = sensor.accelerometer_timestamp;
accel_updates++;
}
if (sensor.baro_timestamp != baro_timestamp) {
corr_baro = baro_offset - sensor.baro_alt_meter - z_est[0];
baro_timestamp = sensor.baro_timestamp;
baro_updates++;
}
}
/* optical flow */
orb_check(optical_flow_sub, &updated);
if (updated) {
orb_copy(ORB_ID(optical_flow), optical_flow_sub, &flow);
/* calculate time from previous update */
float flow_dt = flow_prev > 0 ? (flow.flow_timestamp - flow_prev) * 1e-6f : 0.1f;
flow_prev = flow.flow_timestamp;
if ((flow.ground_distance_m > 0.31f) &&
(flow.ground_distance_m < 4.0f) &&
(att.R[2][2] > 0.7f) &&
(fabsf(flow.ground_distance_m - sonar_prev) > FLT_EPSILON)) {
sonar_time = t;
sonar_prev = flow.ground_distance_m;
corr_sonar = flow.ground_distance_m + surface_offset + z_est[0];
corr_sonar_filtered += (corr_sonar - corr_sonar_filtered) * params.sonar_filt;
if (fabsf(corr_sonar) > params.sonar_err) {
/* correction is too large: spike or new ground level? */
if (fabsf(corr_sonar - corr_sonar_filtered) > params.sonar_err) {
/* spike detected, ignore */
corr_sonar = 0.0f;
sonar_valid = false;
} else {
/* new ground level */
surface_offset -= corr_sonar;
surface_offset_rate = 0.0f;
corr_sonar = 0.0f;
corr_sonar_filtered = 0.0f;
sonar_valid_time = t;
sonar_valid = true;
local_pos.surface_bottom_timestamp = t;
mavlink_log_info(mavlink_fd, "[inav] new surface level: %.2f", (double)surface_offset);
}
} else {
/* correction is ok, use it */
sonar_valid_time = t;
sonar_valid = true;
}
}
float flow_q = flow.quality / 255.0f;
float dist_bottom = - z_est[0] - surface_offset;
if (dist_bottom > 0.3f && flow_q > params.flow_q_min && (t < sonar_valid_time + sonar_valid_timeout) && att.R[2][2] > 0.7f) {
/* distance to surface */
float flow_dist = dist_bottom / att.R[2][2];
/* check if flow if too large for accurate measurements */
/* calculate estimated velocity in body frame */
float body_v_est[2] = { 0.0f, 0.0f };
for (int i = 0; i < 2; i++) {
body_v_est[i] = att.R[0][i] * x_est[1] + att.R[1][i] * y_est[1] + att.R[2][i] * z_est[1];
}
/* set this flag if flow should be accurate according to current velocity and attitude rate estimate */
flow_accurate = fabsf(body_v_est[1] / flow_dist - att.rollspeed) < max_flow &&
fabsf(body_v_est[0] / flow_dist + att.pitchspeed) < max_flow;
/* convert raw flow to angular flow (rad/s) */
float flow_ang[2];
flow_ang[0] = flow.flow_raw_x * params.flow_k / 1000.0f / flow_dt;
flow_ang[1] = flow.flow_raw_y * params.flow_k / 1000.0f / flow_dt;
/* flow measurements vector */
float flow_m[3];
flow_m[0] = -flow_ang[0] * flow_dist;
flow_m[1] = -flow_ang[1] * flow_dist;
flow_m[2] = z_est[1];
/* velocity in NED */
float flow_v[2] = { 0.0f, 0.0f };
/* project measurements vector to NED basis, skip Z component */
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 3; j++) {
flow_v[i] += att.R[i][j] * flow_m[j];
}
}
/* velocity correction */
corr_flow[0] = flow_v[0] - x_est[1];
corr_flow[1] = flow_v[1] - y_est[1];
/* adjust correction weight */
float flow_q_weight = (flow_q - params.flow_q_min) / (1.0f - params.flow_q_min);
w_flow = att.R[2][2] * flow_q_weight / fmaxf(1.0f, flow_dist);
/* if flow is not accurate, reduce weight for it */
// TODO make this more fuzzy
if (!flow_accurate) {
w_flow *= 0.05f;
}
/* under ideal conditions, on 1m distance assume EPH = 10cm */
eph_flow = 0.1f / w_flow;
flow_valid = true;
} else {
w_flow = 0.0f;
flow_valid = false;
}
flow_updates++;
}
/* home position */
orb_check(home_position_sub, &updated);
if (updated) {
orb_copy(ORB_ID(home_position), home_position_sub, &home);
if (home.timestamp != home_timestamp) {
home_timestamp = home.timestamp;
double est_lat, est_lon;
float est_alt;
if (ref_inited) {
/* calculate current estimated position in global frame */
est_alt = local_pos.ref_alt - local_pos.z;
map_projection_reproject(&ref, local_pos.x, local_pos.y, &est_lat, &est_lon);
}
/* update reference */
map_projection_init(&ref, home.lat, home.lon);
/* update baro offset */
baro_offset += home.alt - local_pos.ref_alt;
local_pos.ref_lat = home.lat;
local_pos.ref_lon = home.lon;
local_pos.ref_alt = home.alt;
local_pos.ref_timestamp = home.timestamp;
if (ref_inited) {
/* reproject position estimate with new reference */
map_projection_project(&ref, est_lat, est_lon, &x_est[0], &y_est[0]);
z_est[0] = -(est_alt - local_pos.ref_alt);
}
ref_inited = true;
}
}
/* check no vision circuit breaker is set */
if (params.no_vision != CBRK_NO_VISION_KEY) {
/* vehicle vision position */
orb_check(vision_position_estimate_sub, &updated);
if (updated) {
orb_copy(ORB_ID(vision_position_estimate), vision_position_estimate_sub, &vision);
/* reset position estimate on first vision update */
if (!vision_valid) {
x_est[0] = vision.x;
x_est[1] = vision.vx;
y_est[0] = vision.y;
y_est[1] = vision.vy;
/* only reset the z estimate if the z weight parameter is not zero */
if (params.w_z_vision_p > MIN_VALID_W)
{
z_est[0] = vision.z;
z_est[1] = vision.vz;
}
vision_valid = true;
warnx("VISION estimate valid");
mavlink_log_info(mavlink_fd, "[inav] VISION estimate valid");
}
/* calculate correction for position */
corr_vision[0][0] = vision.x - x_est[0];
corr_vision[1][0] = vision.y - y_est[0];
corr_vision[2][0] = vision.z - z_est[0];
/* calculate correction for velocity */
corr_vision[0][1] = vision.vx - x_est[1];
corr_vision[1][1] = vision.vy - y_est[1];
corr_vision[2][1] = vision.vz - z_est[1];
}
}
/* vehicle GPS position */
orb_check(vehicle_gps_position_sub, &updated);
if (updated) {
orb_copy(ORB_ID(vehicle_gps_position), vehicle_gps_position_sub, &gps);
bool reset_est = false;
/* hysteresis for GPS quality */
if (gps_valid) {
if (gps.eph > max_eph_epv || gps.epv > max_eph_epv || gps.fix_type < 3) {
gps_valid = false;
mavlink_log_info(mavlink_fd, "[inav] GPS signal lost");
}
} else {
if (gps.eph < max_eph_epv * 0.7f && gps.epv < max_eph_epv * 0.7f && gps.fix_type >= 3) {
gps_valid = true;
reset_est = true;
mavlink_log_info(mavlink_fd, "[inav] GPS signal found");
}
}
if (gps_valid) {
double lat = gps.lat * 1e-7;
double lon = gps.lon * 1e-7;
float alt = gps.alt * 1e-3;
/* initialize reference position if needed */
if (!ref_inited) {
if (ref_init_start == 0) {
ref_init_start = t;
} else if (t > ref_init_start + ref_init_delay) {
ref_inited = true;
/* set position estimate to (0, 0, 0), use GPS velocity for XY */
x_est[0] = 0.0f;
x_est[1] = gps.vel_n_m_s;
y_est[0] = 0.0f;
y_est[1] = gps.vel_e_m_s;
local_pos.ref_lat = lat;
local_pos.ref_lon = lon;
local_pos.ref_alt = alt + z_est[0];
local_pos.ref_timestamp = t;
/* initialize projection */
map_projection_init(&ref, lat, lon);
warnx("init ref: lat=%.7f, lon=%.7f, alt=%.2f", (double)lat, (double)lon, (double)alt);
mavlink_log_info(mavlink_fd, "[inav] init ref: %.7f, %.7f, %.2f", (double)lat, (double)lon, (double)alt);
}
}
if (ref_inited) {
/* project GPS lat lon to plane */
float gps_proj[2];
map_projection_project(&ref, lat, lon, &(gps_proj[0]), &(gps_proj[1]));
/* reset position estimate when GPS becomes good */
if (reset_est) {
x_est[0] = gps_proj[0];
x_est[1] = gps.vel_n_m_s;
y_est[0] = gps_proj[1];
y_est[1] = gps.vel_e_m_s;
}
/* calculate index of estimated values in buffer */
int est_i = buf_ptr - 1 - min(EST_BUF_SIZE - 1, max(0, (int)(params.delay_gps * 1000000.0f / PUB_INTERVAL)));
if (est_i < 0) {
est_i += EST_BUF_SIZE;
}
/* calculate correction for position */
corr_gps[0][0] = gps_proj[0] - est_buf[est_i][0][0];
corr_gps[1][0] = gps_proj[1] - est_buf[est_i][1][0];
corr_gps[2][0] = local_pos.ref_alt - alt - est_buf[est_i][2][0];
/* calculate correction for velocity */
if (gps.vel_ned_valid) {
corr_gps[0][1] = gps.vel_n_m_s - est_buf[est_i][0][1];
corr_gps[1][1] = gps.vel_e_m_s - est_buf[est_i][1][1];
corr_gps[2][1] = gps.vel_d_m_s - est_buf[est_i][2][1];
} else {
corr_gps[0][1] = 0.0f;
corr_gps[1][1] = 0.0f;
corr_gps[2][1] = 0.0f;
}
/* save rotation matrix at this moment */
memcpy(R_gps, R_buf[est_i], sizeof(R_gps));
w_gps_xy = min_eph_epv / fmaxf(min_eph_epv, gps.eph);
w_gps_z = min_eph_epv / fmaxf(min_eph_epv, gps.epv);
}
} else {
/* no GPS lock */
memset(corr_gps, 0, sizeof(corr_gps));
ref_init_start = 0;
}
gps_updates++;
}
}
/* check for timeout on FLOW topic */
if ((flow_valid || sonar_valid) && t > flow.timestamp + flow_topic_timeout) {
flow_valid = false;
sonar_valid = false;
warnx("FLOW timeout");
mavlink_log_info(mavlink_fd, "[inav] FLOW timeout");
}
/* check for timeout on GPS topic */
if (gps_valid && (t > (gps.timestamp_position + gps_topic_timeout))) {
gps_valid = false;
warnx("GPS timeout");
mavlink_log_info(mavlink_fd, "[inav] GPS timeout");
}
/* check for timeout on vision topic */
if (vision_valid && (t > (vision.timestamp_boot + vision_topic_timeout))) {
vision_valid = false;
warnx("VISION timeout");
mavlink_log_info(mavlink_fd, "[inav] VISION timeout");
}
/* check for sonar measurement timeout */
if (sonar_valid && (t > (sonar_time + sonar_timeout))) {
corr_sonar = 0.0f;
sonar_valid = false;
}
float dt = t_prev > 0 ? (t - t_prev) / 1000000.0f : 0.0f;
dt = fmaxf(fminf(0.02, dt), 0.002); // constrain dt from 2 to 20 ms
t_prev = t;
/* increase EPH/EPV on each step */
if (eph < max_eph_epv) {
eph *= 1.0f + dt;
}
if (epv < max_eph_epv) {
epv += 0.005f * dt; // add 1m to EPV each 200s (baro drift)
}
/* use GPS if it's valid and reference position initialized */
bool use_gps_xy = ref_inited && gps_valid && params.w_xy_gps_p > MIN_VALID_W;
bool use_gps_z = ref_inited && gps_valid && params.w_z_gps_p > MIN_VALID_W;
/* use VISION if it's valid and has a valid weight parameter */
bool use_vision_xy = vision_valid && params.w_xy_vision_p > MIN_VALID_W;
bool use_vision_z = vision_valid && params.w_z_vision_p > MIN_VALID_W;
/* use flow if it's valid and (accurate or no GPS available) */
bool use_flow = flow_valid && (flow_accurate || !use_gps_xy);
bool can_estimate_xy = (eph < max_eph_epv) || use_gps_xy || use_flow || use_vision_xy;
bool dist_bottom_valid = (t < sonar_valid_time + sonar_valid_timeout);
if (dist_bottom_valid) {
/* surface distance prediction */
surface_offset += surface_offset_rate * dt;
/* surface distance correction */
if (sonar_valid) {
surface_offset_rate -= corr_sonar * 0.5f * params.w_z_sonar * params.w_z_sonar * dt;
surface_offset -= corr_sonar * params.w_z_sonar * dt;
}
}
float w_xy_gps_p = params.w_xy_gps_p * w_gps_xy;
float w_xy_gps_v = params.w_xy_gps_v * w_gps_xy;
float w_z_gps_p = params.w_z_gps_p * w_gps_z;
float w_xy_vision_p = params.w_xy_vision_p;
float w_xy_vision_v = params.w_xy_vision_v;
float w_z_vision_p = params.w_z_vision_p;
/* reduce GPS weight if optical flow is good */
if (use_flow && flow_accurate) {
w_xy_gps_p *= params.w_gps_flow;
w_xy_gps_v *= params.w_gps_flow;
}
/* baro offset correction */
if (use_gps_z) {
float offs_corr = corr_gps[2][0] * w_z_gps_p * dt;
baro_offset += offs_corr;
corr_baro += offs_corr;
}
/* accelerometer bias correction for GPS (use buffered rotation matrix) */
float accel_bias_corr[3] = { 0.0f, 0.0f, 0.0f };
if (use_gps_xy) {
accel_bias_corr[0] -= corr_gps[0][0] * w_xy_gps_p * w_xy_gps_p;
accel_bias_corr[0] -= corr_gps[0][1] * w_xy_gps_v;
accel_bias_corr[1] -= corr_gps[1][0] * w_xy_gps_p * w_xy_gps_p;
accel_bias_corr[1] -= corr_gps[1][1] * w_xy_gps_v;
}
if (use_gps_z) {
accel_bias_corr[2] -= corr_gps[2][0] * w_z_gps_p * w_z_gps_p;
}
/* transform error vector from NED frame to body frame */
for (int i = 0; i < 3; i++) {
float c = 0.0f;
for (int j = 0; j < 3; j++) {
c += R_gps[j][i] * accel_bias_corr[j];
}
if (isfinite(c)) {
acc_bias[i] += c * params.w_acc_bias * dt;
}
}
/* accelerometer bias correction for VISION (use buffered rotation matrix) */
accel_bias_corr[0] = 0.0f;
accel_bias_corr[1] = 0.0f;
accel_bias_corr[2] = 0.0f;
if (use_vision_xy) {
accel_bias_corr[0] -= corr_vision[0][0] * w_xy_vision_p * w_xy_vision_p;
accel_bias_corr[0] -= corr_vision[0][1] * w_xy_vision_v;
accel_bias_corr[1] -= corr_vision[1][0] * w_xy_vision_p * w_xy_vision_p;
accel_bias_corr[1] -= corr_vision[1][1] * w_xy_vision_v;
}
if (use_vision_z) {
accel_bias_corr[2] -= corr_vision[2][0] * w_z_vision_p * w_z_vision_p;
}
/* transform error vector from NED frame to body frame */
for (int i = 0; i < 3; i++) {
float c = 0.0f;
for (int j = 0; j < 3; j++) {
c += att.R[j][i] * accel_bias_corr[j];
}
if (isfinite(c)) {
acc_bias[i] += c * params.w_acc_bias * dt;
}
}
/* accelerometer bias correction for flow and baro (assume that there is no delay) */
accel_bias_corr[0] = 0.0f;
accel_bias_corr[1] = 0.0f;
accel_bias_corr[2] = 0.0f;
if (use_flow) {
accel_bias_corr[0] -= corr_flow[0] * params.w_xy_flow;
accel_bias_corr[1] -= corr_flow[1] * params.w_xy_flow;
}
accel_bias_corr[2] -= corr_baro * params.w_z_baro * params.w_z_baro;
/* transform error vector from NED frame to body frame */
for (int i = 0; i < 3; i++) {
float c = 0.0f;
for (int j = 0; j < 3; j++) {
c += att.R[j][i] * accel_bias_corr[j];
}
if (isfinite(c)) {
acc_bias[i] += c * params.w_acc_bias * dt;
}
}
/* inertial filter prediction for altitude */
inertial_filter_predict(dt, z_est, acc[2]);
if (!(isfinite(z_est[0]) && isfinite(z_est[1]))) {
write_debug_log("BAD ESTIMATE AFTER Z PREDICTION", dt, x_est, y_est, z_est, x_est_prev, y_est_prev, z_est_prev, acc, corr_gps, w_xy_gps_p, w_xy_gps_v);
memcpy(z_est, z_est_prev, sizeof(z_est));
}
/* inertial filter correction for altitude */
inertial_filter_correct(corr_baro, dt, z_est, 0, params.w_z_baro);
if (use_gps_z) {
epv = fminf(epv, gps.epv);
inertial_filter_correct(corr_gps[2][0], dt, z_est, 0, w_z_gps_p);
}
if (use_vision_z) {
epv = fminf(epv, epv_vision);
inertial_filter_correct(corr_vision[2][0], dt, z_est, 0, w_z_vision_p);
}
if (!(isfinite(z_est[0]) && isfinite(z_est[1]))) {
write_debug_log("BAD ESTIMATE AFTER Z CORRECTION", dt, x_est, y_est, z_est, x_est_prev, y_est_prev, z_est_prev, acc, corr_gps, w_xy_gps_p, w_xy_gps_v);
memcpy(z_est, z_est_prev, sizeof(z_est));
memset(corr_gps, 0, sizeof(corr_gps));
memset(corr_vision, 0, sizeof(corr_vision));
corr_baro = 0;
} else {
memcpy(z_est_prev, z_est, sizeof(z_est));
}
if (can_estimate_xy) {
/* inertial filter prediction for position */
inertial_filter_predict(dt, x_est, acc[0]);
inertial_filter_predict(dt, y_est, acc[1]);
if (!(isfinite(x_est[0]) && isfinite(x_est[1]) && isfinite(y_est[0]) && isfinite(y_est[1]))) {
write_debug_log("BAD ESTIMATE AFTER PREDICTION", dt, x_est, y_est, z_est, x_est_prev, y_est_prev, z_est_prev, acc, corr_gps, w_xy_gps_p, w_xy_gps_v);
memcpy(x_est, x_est_prev, sizeof(x_est));
memcpy(y_est, y_est_prev, sizeof(y_est));
}
/* inertial filter correction for position */
if (use_flow) {
eph = fminf(eph, eph_flow);
inertial_filter_correct(corr_flow[0], dt, x_est, 1, params.w_xy_flow * w_flow);
inertial_filter_correct(corr_flow[1], dt, y_est, 1, params.w_xy_flow * w_flow);
}
if (use_gps_xy) {
eph = fminf(eph, gps.eph);
inertial_filter_correct(corr_gps[0][0], dt, x_est, 0, w_xy_gps_p);
inertial_filter_correct(corr_gps[1][0], dt, y_est, 0, w_xy_gps_p);
if (gps.vel_ned_valid && t < gps.timestamp_velocity + gps_topic_timeout) {
inertial_filter_correct(corr_gps[0][1], dt, x_est, 1, w_xy_gps_v);
inertial_filter_correct(corr_gps[1][1], dt, y_est, 1, w_xy_gps_v);
}
}
if (use_vision_xy) {
eph = fminf(eph, eph_vision);
inertial_filter_correct(corr_vision[0][0], dt, x_est, 0, w_xy_vision_p);
inertial_filter_correct(corr_vision[1][0], dt, y_est, 0, w_xy_vision_p);
if (w_xy_vision_v > MIN_VALID_W) {
inertial_filter_correct(corr_vision[0][1], dt, x_est, 1, w_xy_vision_v);
inertial_filter_correct(corr_vision[1][1], dt, y_est, 1, w_xy_vision_v);
}
}
if (!(isfinite(x_est[0]) && isfinite(x_est[1]) && isfinite(y_est[0]) && isfinite(y_est[1]))) {
write_debug_log("BAD ESTIMATE AFTER CORRECTION", dt, x_est, y_est, z_est, x_est_prev, y_est_prev, z_est_prev, acc, corr_gps, w_xy_gps_p, w_xy_gps_v);
memcpy(x_est, x_est_prev, sizeof(x_est));
memcpy(y_est, y_est_prev, sizeof(y_est));
memset(corr_gps, 0, sizeof(corr_gps));
memset(corr_vision, 0, sizeof(corr_vision));
memset(corr_flow, 0, sizeof(corr_flow));
} else {
memcpy(x_est_prev, x_est, sizeof(x_est));
memcpy(y_est_prev, y_est, sizeof(y_est));
}
} else {
/* gradually reset xy velocity estimates */
inertial_filter_correct(-x_est[1], dt, x_est, 1, params.w_xy_res_v);
inertial_filter_correct(-y_est[1], dt, y_est, 1, params.w_xy_res_v);
}
/* detect land */
alt_avg += (- z_est[0] - alt_avg) * dt / params.land_t;
float alt_disp2 = - z_est[0] - alt_avg;
alt_disp2 = alt_disp2 * alt_disp2;
float land_disp2 = params.land_disp * params.land_disp;
/* get actual thrust output */
float thrust = armed.armed ? actuator.control[3] : 0.0f;
if (landed) {
if (alt_disp2 > land_disp2 || thrust > params.land_thr) {
landed = false;
landed_time = 0;
}
/* reset xy velocity estimates when landed */
x_est[1] = 0.0f;
y_est[1] = 0.0f;
} else {
if (alt_disp2 < land_disp2 && thrust < params.land_thr) {
if (landed_time == 0) {
landed_time = t; // land detected first time
} else {
if (t > landed_time + params.land_t * 1000000.0f) {
landed = true;
landed_time = 0;
}
}
} else {
landed_time = 0;
}
}
if (verbose_mode) {
/* print updates rate */
if (t > updates_counter_start + updates_counter_len) {
float updates_dt = (t - updates_counter_start) * 0.000001f;
warnx(
"updates rate: accelerometer = %.1f/s, baro = %.1f/s, gps = %.1f/s, attitude = %.1f/s, flow = %.1f/s",
(double)(accel_updates / updates_dt),
(double)(baro_updates / updates_dt),
(double)(gps_updates / updates_dt),
(double)(attitude_updates / updates_dt),
(double)(flow_updates / updates_dt));
updates_counter_start = t;
accel_updates = 0;
baro_updates = 0;
gps_updates = 0;
attitude_updates = 0;
flow_updates = 0;
}
}
if (t > pub_last + PUB_INTERVAL) {
pub_last = t;
/* push current estimate to buffer */
est_buf[buf_ptr][0][0] = x_est[0];
est_buf[buf_ptr][0][1] = x_est[1];
est_buf[buf_ptr][1][0] = y_est[0];
est_buf[buf_ptr][1][1] = y_est[1];
est_buf[buf_ptr][2][0] = z_est[0];
est_buf[buf_ptr][2][1] = z_est[1];
/* push current rotation matrix to buffer */
memcpy(R_buf[buf_ptr], att.R, sizeof(att.R));
buf_ptr++;
if (buf_ptr >= EST_BUF_SIZE) {
buf_ptr = 0;
}
/* publish local position */
local_pos.xy_valid = can_estimate_xy;
local_pos.v_xy_valid = can_estimate_xy;
local_pos.xy_global = local_pos.xy_valid && use_gps_xy;
local_pos.z_global = local_pos.z_valid && use_gps_z;
local_pos.x = x_est[0];
local_pos.vx = x_est[1];
local_pos.y = y_est[0];
local_pos.vy = y_est[1];
local_pos.z = z_est[0];
local_pos.vz = z_est[1];
local_pos.landed = landed;
local_pos.yaw = att.yaw;
local_pos.dist_bottom_valid = dist_bottom_valid;
local_pos.eph = eph;
local_pos.epv = epv;
if (local_pos.dist_bottom_valid) {
local_pos.dist_bottom = -z_est[0] - surface_offset;
local_pos.dist_bottom_rate = -z_est[1] - surface_offset_rate;
}
local_pos.timestamp = t;
orb_publish(ORB_ID(vehicle_local_position), vehicle_local_position_pub, &local_pos);
if (local_pos.xy_global && local_pos.z_global) {
/* publish global position */
global_pos.timestamp = t;
global_pos.time_gps_usec = gps.time_gps_usec;
double est_lat, est_lon;
map_projection_reproject(&ref, local_pos.x, local_pos.y, &est_lat, &est_lon);
global_pos.lat = est_lat;
global_pos.lon = est_lon;
global_pos.alt = local_pos.ref_alt - local_pos.z;
global_pos.vel_n = local_pos.vx;
global_pos.vel_e = local_pos.vy;
global_pos.vel_d = local_pos.vz;
global_pos.yaw = local_pos.yaw;
global_pos.eph = eph;
global_pos.epv = epv;
if (vehicle_global_position_pub < 0) {
vehicle_global_position_pub = orb_advertise(ORB_ID(vehicle_global_position), &global_pos);
} else {
orb_publish(ORB_ID(vehicle_global_position), vehicle_global_position_pub, &global_pos);
}
}
}
}
warnx("stopped");
mavlink_log_info(mavlink_fd, "[inav] stopped");
thread_running = false;
return 0;
}