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author | Lorenz Meier <lm@inf.ethz.ch> | 2012-09-22 18:44:01 +0200 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2012-09-22 18:46:04 +0200 |
commit | a9b21886f32d0a8ef7cad8dfe7efbc3276f4fd58 (patch) | |
tree | 49205188c750a90d46a429f92294a3dbe19f8bde /apps/systemlib/geo/geo.c | |
parent | c265e07ae0114d3ecea577aaf4d41d17753d955b (diff) | |
download | px4-firmware-a9b21886f32d0a8ef7cad8dfe7efbc3276f4fd58.tar.gz px4-firmware-a9b21886f32d0a8ef7cad8dfe7efbc3276f4fd58.tar.bz2 px4-firmware-a9b21886f32d0a8ef7cad8dfe7efbc3276f4fd58.zip |
Halfway-working fixed wing waypoint control, needs more effort
Diffstat (limited to 'apps/systemlib/geo/geo.c')
-rw-r--r-- | apps/systemlib/geo/geo.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/apps/systemlib/geo/geo.c b/apps/systemlib/geo/geo.c new file mode 100644 index 000000000..42d8d9c15 --- /dev/null +++ b/apps/systemlib/geo/geo.c @@ -0,0 +1,88 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * Author: 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 geo.c + * + * Geo / math functions to perform geodesic calculations + * + * @author Thomas Gubler <thomasgubler@student.ethz.ch> + * @author Julian Oes <joes@student.ethz.ch> + * @author Lorenz Meier <lm@inf.ethz.ch> + */ + +#include <systemlib/geo/geo.h> +#include <math.h> + +__EXPORT float get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next) +{ + double lat_now_rad = lat_now / 180.0 * M_PI; + double lon_now_rad = lon_now / 180.0 * M_PI; + double lat_next_rad = lat_next / 180.0 * M_PI; + double lon_next_rad = lon_next / 180.0 * M_PI; + + + double d_lat = lat_next_rad - lat_now_rad; + double d_lon = lon_next_rad - lon_now_rad; + + double a = sin(d_lat / 2.0) * sin(d_lat / 2.0) + sin(d_lon / 2.0) * sin(d_lon / 2.0) * cos(lat_now_rad) * cos(lat_next_rad); + double c = 2 * atan2(sqrt(a), sqrt(1 - a)); + + const double radius_earth = 6371000.0; + + return radius_earth * c; +} + +__EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next) +{ + double lat_now_rad = lat_now / 180.0 * M_PI; + double lon_now_rad = lon_now / 180.0 * M_PI; + double lat_next_rad = lat_next / 180.0 * M_PI; + double lon_next_rad = lon_next / 180.0 * M_PI; + + double d_lat = lat_next_rad - lat_now_rad; + double d_lon = lon_next_rad - lon_now_rad; + + /* conscious mix of double and float trig function to maximize speed and efficiency */ + float theta = atan2f(sin(d_lon) * cos(lat_next_rad) , cos(lat_now_rad) * sin(lat_next_rad) - sin(lat_now_rad) * cos(lat_next_rad) * cos(d_lon)); + + // XXX wrapping check is incomplete + if (theta < 0.0f) { + theta = theta + 2.0f * M_PI_F; + } + + return theta; +}
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