diff options
Diffstat (limited to 'apps/position_estimator/position_estimator_main.c')
-rw-r--r-- | apps/position_estimator/position_estimator_main.c | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/apps/position_estimator/position_estimator_main.c b/apps/position_estimator/position_estimator_main.c new file mode 100644 index 000000000..773cd87ff --- /dev/null +++ b/apps/position_estimator/position_estimator_main.c @@ -0,0 +1,425 @@ +/**************************************************************************** + * + * Copyright (C) 2008-2012 PX4 Development Team. All rights reserved. + * Author: Tobias Naegeli <naegelit@student.ethz.ch> + * Thomas Gubler <thomasgubler@student.ethz.ch> + * Julian Oes <joes@student.ethz.ch> + * Lorenz Meier <lm@inf.ethz.ch> + * + * 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 + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * 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 Model-identification based position estimator for multirotors + */ + +#include <nuttx/config.h> +#include <unistd.h> +#include <stdlib.h> +#include <stdio.h> +#include <stdbool.h> +#include <fcntl.h> +#include <v1.0/common/mavlink.h> +#include <float.h> +#include <nuttx/sched.h> +#include <sys/prctl.h> +#include <termios.h> +#include <errno.h> +#include <limits.h> +#include <math.h> +#include <uORB/uORB.h> +#include <uORB/topics/vehicle_status.h> +#include <uORB/topics/vehicle_attitude.h> +#include <uORB/topics/vehicle_gps_position.h> +#include <uORB/topics/vehicle_global_position.h> +#include <poll.h> + +#include "codegen/position_estimator.h" + +#define N_STATES 6 +#define ERROR_COVARIANCE_INIT 3 +#define R_EARTH 6371000.0 + +#define PROJECTION_INITIALIZE_COUNTER_LIMIT 5000 +#define REPROJECTION_COUNTER_LIMIT 125 + +__EXPORT int position_estimator_main(int argc, char *argv[]); + +static uint16_t position_estimator_counter_position_information; + +/* values for map projection */ +static double phi_1; +static double sin_phi_1; +static double cos_phi_1; +static double lambda_0; +static double scale; + +/** + * Initializes the map transformation. + * + * Initializes the transformation between the geographic coordinate system and the azimuthal equidistant plane + * @param lat in degrees (47.1234567°, not 471234567°) + * @param lon in degrees (8.1234567°, not 81234567°) + */ +static void map_projection_init(double lat_0, double lon_0) //lat_0, lon_0 are expected to be in correct format: -> 47.1234567 and not 471234567 +{ + /* notation and formulas according to: http://mathworld.wolfram.com/AzimuthalEquidistantProjection.html */ + phi_1 = lat_0 / 180.0 * M_PI; + lambda_0 = lon_0 / 180.0 * M_PI; + + sin_phi_1 = sin(phi_1); + cos_phi_1 = cos(phi_1); + + /* calculate local scale by using the relation of true distance and the distance on plane */ //TODO: this is a quick solution, there are probably easier ways to determine the scale + + /* 1) calculate true distance d on sphere to a point: http://www.movable-type.co.uk/scripts/latlong.html */ + const double r_earth = 6371000; + + double lat1 = phi_1; + double lon1 = lambda_0; + + double lat2 = phi_1 + 0.5 / 180 * M_PI; + double lon2 = lambda_0 + 0.5 / 180 * M_PI; + double sin_lat_2 = sin(lat2); + double cos_lat_2 = cos(lat2); + double d = acos(sin(lat1) * sin_lat_2 + cos(lat1) * cos_lat_2 * cos(lon2 - lon1)) * r_earth; + + /* 2) calculate distance rho on plane */ + double k_bar = 0; + double c = acos(sin_phi_1 * sin_lat_2 + cos_phi_1 * cos_lat_2 * cos(lon2 - lambda_0)); + + if (0 != c) + k_bar = c / sin(c); + + double x2 = k_bar * (cos_lat_2 * sin(lon2 - lambda_0)); //Projection of point 2 on plane + double y2 = k_bar * ((cos_phi_1 * sin_lat_2 - sin_phi_1 * cos_lat_2 * cos(lon2 - lambda_0))); + double rho = sqrt(pow(x2, 2) + pow(y2, 2)); + + scale = d / rho; + +} + +/** + * Transforms a point in the geographic coordinate system to the local azimuthal equidistant plane + * @param x north + * @param y east + * @param lat in degrees (47.1234567°, not 471234567°) + * @param lon in degrees (8.1234567°, not 81234567°) + */ +static void map_projection_project(double lat, double lon, float *x, float *y) +{ + /* notation and formulas accoring to: http://mathworld.wolfram.com/AzimuthalEquidistantProjection.html */ + double phi = lat / 180.0 * M_PI; + double lambda = lon / 180.0 * M_PI; + + double sin_phi = sin(phi); + double cos_phi = cos(phi); + + double k_bar = 0; + /* using small angle approximation (formula in comment is without aproximation) */ + double c = acos(sin_phi_1 * sin_phi + cos_phi_1 * cos_phi * (1 - pow((lambda - lambda_0), 2) / 2)); //double c = acos( sin_phi_1 * sin_phi + cos_phi_1 * cos_phi * cos(lambda - lambda_0) ); + + if (0 != c) + k_bar = c / sin(c); + + /* using small angle approximation (formula in comment is without aproximation) */ + *y = k_bar * (cos_phi * (lambda - lambda_0)) * scale;//*y = k_bar * (cos_phi * sin(lambda - lambda_0)) * scale; + *x = k_bar * ((cos_phi_1 * sin_phi - sin_phi_1 * cos_phi * (1 - pow((lambda - lambda_0), 2) / 2))) * scale; // *x = k_bar * ((cos_phi_1 * sin_phi - sin_phi_1 * cos_phi * cos(lambda - lambda_0))) * scale; + +// printf("%phi_1=%.10f, lambda_0 =%.10f\n", phi_1, lambda_0); +} + +/** + * Transforms a point in the local azimuthal equidistant plane to the geographic coordinate system + * + * @param x north + * @param y east + * @param lat in degrees (47.1234567°, not 471234567°) + * @param lon in degrees (8.1234567°, not 81234567°) + */ +static void map_projection_reproject(float x, float y, double *lat, double *lon) +{ + /* notation and formulas accoring to: http://mathworld.wolfram.com/AzimuthalEquidistantProjection.html */ + + double x_descaled = x / scale; + double y_descaled = y / scale; + + double c = sqrt(pow(x_descaled, 2) + pow(y_descaled, 2)); + double sin_c = sin(c); + double cos_c = cos(c); + + double lat_sphere = 0; + + if (c != 0) + lat_sphere = asin(cos_c * sin_phi_1 + (x_descaled * sin_c * cos_phi_1) / c); + else + lat_sphere = asin(cos_c * sin_phi_1); + +// printf("lat_sphere = %.10f\n",lat_sphere); + + double lon_sphere = 0; + + if (phi_1 == M_PI / 2) { + //using small angle approximation (formula in comment is without aproximation) + lon_sphere = (lambda_0 - y_descaled / x_descaled); //lon_sphere = (lambda_0 + atan2(-y_descaled, x_descaled)); + + } else if (phi_1 == -M_PI / 2) { + //using small angle approximation (formula in comment is without aproximation) + lon_sphere = (lambda_0 + y_descaled / x_descaled); //lon_sphere = (lambda_0 + atan2(y_descaled, x_descaled)); + + } else { + + lon_sphere = (lambda_0 + atan2(y_descaled * sin_c , c * cos_phi_1 * cos_c - x_descaled * sin_phi_1 * sin_c)); + //using small angle approximation +// double denominator = (c * cos_phi_1 * cos_c - x_descaled * sin_phi_1 * sin_c); +// if(denominator != 0) +// { +// lon_sphere = (lambda_0 + (y_descaled * sin_c) / denominator); +// } +// else +// { +// ... +// } + } + +// printf("lon_sphere = %.10f\n",lon_sphere); + + *lat = lat_sphere * 180.0 / M_PI; + *lon = lon_sphere * 180.0 / M_PI; + +} + +/**************************************************************************** + * main + ****************************************************************************/ + +int position_estimator_main(int argc, char *argv[]) +{ + + /* welcome user */ + printf("[multirotor position_estimator] started\n"); + + /* initialize values */ + static float u[2] = {0, 0}; + static float z[3] = {0, 0, 0}; + static float xapo[N_STATES] = {0, 0, 0, 0, 0, 0}; + static float Papo[N_STATES * N_STATES] = {ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0, + ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0, + ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0, + ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0, + ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0, + ERROR_COVARIANCE_INIT, 0, 0, 0, 0, 0 + }; + + static float xapo1[N_STATES]; + static float Papo1[36]; + + static float gps_covariance[3] = {0.0f, 0.0f, 0.0f}; + + static uint16_t counter = 0; + position_estimator_counter_position_information = 0; + + uint8_t predict_only = 1; + + bool gps_valid = false; + + bool new_initialization = true; + + static double lat_current = 0;//[°]] --> 47.0 + static double lon_current = 0; //[°]] -->8.5 + + + //TODO: handle flight without gps but with estimator + + /* subscribe to vehicle status, attitude, gps */ + struct vehicle_gps_position_s gps; + struct vehicle_status_s vstatus; + struct vehicle_attitude_s att; + + int vehicle_gps_sub = orb_subscribe(ORB_ID(vehicle_gps_position)); + int vehicle_status_sub = orb_subscribe(ORB_ID(vehicle_status)); + + /* subscribe to attitude at 100 Hz */ + int vehicle_attitude_sub = orb_subscribe(ORB_ID(vehicle_attitude)); + + /* wait until gps signal turns valid, only then can we initialize the projection */ + while (!gps_valid) { + struct pollfd fds[1] = { {.fd = vehicle_gps_sub, .events = POLLIN} }; + + /* wait for GPS updates, BUT READ VEHICLE STATUS (!) + * this choice is critical, since the vehicle status might not + * actually change, if this app is started after GPS lock was + * aquired. + */ + if (poll(fds, 1, 5000)) { + /* Wait for the GPS update to propagate (we have some time) */ + usleep(5000); + /* Read wether the vehicle status changed */ + orb_copy(ORB_ID(vehicle_status), vehicle_status_sub, &vstatus); + gps_valid = vstatus.gps_valid; + } + } + + /* get gps value for first initialization */ + orb_copy(ORB_ID(vehicle_gps_position), vehicle_gps_sub, &gps); + lat_current = ((double)(gps.lat)) * 1e-7; + lon_current = ((double)(gps.lon)) * 1e-7; + + /* publish global position messages only after first GPS message */ + struct vehicle_global_position_s global_pos = { + .lat = lat_current * 1e7, + .lon = lon_current * 1e7, + .alt = gps.alt + }; + int global_pos_pub = orb_advertise(ORB_ID(vehicle_global_position), &global_pos); + + printf("[multirotor position estimator] initialized projection with: lat: %.10f, lon:%.10f\n", lat_current, lon_current); + + while (1) { + + /*This runs at the rate of the sensors, if we have also a new gps update this is used in the position_estimator function */ + struct pollfd fds[1] = { {.fd = vehicle_attitude_sub, .events = POLLIN} }; + + if (poll(fds, 1, 5000) <= 0) { + /* error / timeout */ + } else { + + orb_copy(ORB_ID(vehicle_attitude), vehicle_attitude_sub, &att); + /* got attitude, updating pos as well */ + orb_copy(ORB_ID(vehicle_gps_position), vehicle_gps_sub, &gps); + orb_copy(ORB_ID(vehicle_status), vehicle_status_sub, &vstatus); + + /*copy attitude */ + u[0] = att.roll; + u[1] = att.pitch; + + /* initialize map projection with the last estimate (not at full rate) */ + if (counter % PROJECTION_INITIALIZE_COUNTER_LIMIT == 0) { + map_projection_init(lat_current, lon_current); + new_initialization = true; + + } else { + new_initialization = false; + } + + /*check if new gps values are available */ + gps_valid = vstatus.gps_valid; + + + if (gps_valid) { //we are safe to use the gps signal (it has good quality) + + predict_only = 0; + /* Project gps lat lon (Geographic coordinate system) to plane*/ + map_projection_project((double)(gps.lat) * 1e-7, (double)(gps.lon) * 1e-7, &(z[0]), &(z[1])); + + /* copy altitude */ + z[2] = (gps.alt) * 1e-3; + + gps_covariance[0] = gps.eph; //TODO: needs scaling + gps_covariance[1] = gps.eph; + gps_covariance[2] = gps.epv; + + } else { + /* we can not use the gps signal (it is of low quality) */ + predict_only = 1; + } + + // predict_only = 0; //TODO: only for testing, removeme, XXX + // z[0] = sinf(((float)counter)/180.0f*3.14159265f); //TODO: only for testing, removeme, XXX + // usleep(100000); //TODO: only for testing, removeme, XXX + + + /*Get new estimation (this is calculated in the plane) */ + //TODO: if new_initialization == true: use 0,0,0, else use xapo + if (true == new_initialization) { //TODO,XXX: uncomment! + xapo[0] = 0; //we have a new plane initialization. the current estimate is in the center of the plane + xapo[2] = 0; + xapo[4] = 0; + position_estimator(u, z, xapo, Papo, gps_covariance, predict_only, xapo1, Papo1); + + } else { + position_estimator(u, z, xapo, Papo, gps_covariance, predict_only, xapo1, Papo1); + } + + + + /* Copy values from xapo1 to xapo */ + int i; + + for (i = 0; i < N_STATES; i++) { + xapo[i] = xapo1[i]; + } + + if ((counter % REPROJECTION_COUNTER_LIMIT == 0) || (counter % (PROJECTION_INITIALIZE_COUNTER_LIMIT - 1) == 0)) { + /* Reproject from plane to geographic coordinate system */ + // map_projection_reproject(xapo1[0], xapo1[2], map_scale, phi_1, lambda_0, &lat_current, &lon_current) //TODO,XXX: uncomment! + map_projection_reproject(z[0], z[1], &lat_current, &lon_current); //do not use estimator for projection testing, removeme + // //DEBUG + // if(counter%500 == 0) + // { + // printf("phi_1: %.10f\n", phi_1); + // printf("lambda_0: %.10f\n", lambda_0); + // printf("lat_estimated: %.10f\n", lat_current); + // printf("lon_estimated: %.10f\n", lon_current); + // printf("z[0]=%.10f, z[1]=%.10f, z[2]=%f\n", z[0], z[1], z[2]); + // fflush(stdout); + // + // } + + // if(!isnan(lat_current) && !isnan(lon_current))// && !isnan(xapo1[4]) && !isnan(xapo1[1]) && !isnan(xapo1[3]) && !isnan(xapo1[5])) + // { + /* send out */ + + global_pos.lat = lat_current; + global_pos.lon = lon_current; + global_pos.alt = xapo1[4]; + global_pos.vx = xapo1[1]; + global_pos.vy = xapo1[3]; + global_pos.vz = xapo1[5]; + + /* publish current estimate */ + orb_publish(ORB_ID(vehicle_global_position), global_pos_pub, &global_pos); + // } + // else + // { + // printf("[position estimator] ERROR: nan values, lat_current=%.4f, lon_current=%.4f, z[0]=%.4f z[1]=%.4f\n", lat_current, lon_current, z[0], z[1]); + // fflush(stdout); + // } + + } + + counter++; + } + + } + + return 0; +} + + |