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authorLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
committerLorenz Meier <lm@inf.ethz.ch>2013-04-28 09:54:11 +0200
commit13fc6703862862f4263d8d5d085b7a16b87190e1 (patch)
tree47f3a17cb6f38b1aafe22e1cdef085cd73cd3a1d /src/modules/systemlib/conversions.h
parentf57439b90e23de260259dec051d3e2ead2d61c8c (diff)
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Moved last libs, drivers and headers, cleaned up IO build
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+/****************************************************************************
+ *
+ * Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ * Author: 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 conversions.h
+ * Definition of commonly used conversions.
+ *
+ * Includes bit / byte / geo representation and unit conversions.
+ */
+
+#ifndef CONVERSIONS_H_
+#define CONVERSIONS_H_
+#include <float.h>
+#include <stdint.h>
+
+#define CONSTANTS_ONE_G 9.80665f // m/s^2
+#define CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C 1.225f // kg/m^3
+#define CONSTANTS_AIR_GAS_CONST 287.1f // J/(kg * K)
+#define CONSTANTS_ABSOLUTE_NULL_CELSIUS -273.15f // °C
+
+__BEGIN_DECLS
+
+/**
+ * Converts a signed 16 bit integer from big endian to little endian.
+ *
+ * This function is for commonly used 16 bit big endian sensor data,
+ * delivered by driver routines as two 8 bit numbers in big endian order.
+ * Common vendors with big endian representation are Invense, Bosch and
+ * Honeywell. ST micro devices tend to use a little endian representation.
+ */
+__EXPORT int16_t int16_t_from_bytes(uint8_t bytes[]);
+
+/**
+ * Converts a 3 x 3 rotation matrix to an unit quaternion.
+ *
+ * All orientations are expressed in NED frame.
+ *
+ * @param R rotation matrix to convert
+ * @param Q quaternion to write back to
+ */
+__EXPORT void rot2quat(const float R[9], float Q[4]);
+
+/**
+ * Converts an unit quaternion to a 3 x 3 rotation matrix.
+ *
+ * All orientations are expressed in NED frame.
+ *
+ * @param Q quaternion to convert
+ * @param R rotation matrix to write back to
+ */
+__EXPORT void quat2rot(const float Q[4], float R[9]);
+
+/**
+ * Calculates air density.
+ *
+ * @param static_pressure ambient pressure in millibar
+ * @param temperature_celcius air / ambient temperature in celcius
+ */
+__EXPORT float get_air_density(float static_pressure, float temperature_celsius);
+
+__END_DECLS
+
+#endif /* CONVERSIONS_H_ */