added file with ekf helper functions

EKF/ekf_helper.cpp

@@ -0,0 +1,72 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2015 Estimation and Control Library (ECL). 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 ECL 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 ekf_helper.cpp
+ * Definition of ekf helper functions.
+ *
+ * @author Roman Bast <bapstroman@gmail.com>
+ *
+ */
+
+#include "ekf.h"
+
+void Ekf::resetVelocity()
+{
+	// if we have a valid GPS measurement use it to initialise velocity states
+	gpsSample gps_newest = _gps_buffer.get_newest();
+
+	if (_time_last_imu - gps_newest.time_us < 100000) {
+		_state.vel = gps_newest.vel;
+
+	} else {
+		_state.vel.setZero();
+	}
+}
+
+void Ekf::resetPosition()
+{
+	// if we have a valid GPS measurement use it to initialise position states
+	gpsSample gps_newest = _gps_buffer.get_newest();
+
+	if (_time_last_imu - gps_newest.time_us < 100000) {
+		_state.pos(0) = gps_newest.pos(0);
+		_state.pos(1) = gps_newest.pos(1);
+
+	} else {
+		// XXX use the value of the last known position
+	}
+
+	baroSample baro_newest = _baro_buffer.get_newest();
+	_state.pos(2) = baro_newest.hgt;
+}