Halfway-working fixed wing waypoint control, needs more effort

2 files changed, 137 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;
+}
\ No newline at end of file
diff --git a/apps/systemlib/geo/geo.h b/apps/systemlib/geo/geo.h
new file mode 100644
index 000000000..0e86b3599
--- /dev/null
+++ b/apps/systemlib/geo/geo.h
@@ -0,0 +1,49 @@
+/****************************************************************************
+ *
+ *   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.h
+ *
+ * Definition of 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>
+ */
+
+__EXPORT float get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);
+
+__EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);