Merge branch 'master' into vector_control

27 files changed, 1023 insertions, 774 deletions

diff --git a/src/modules/systemlib/airspeed.c b/src/modules/systemlib/airspeed.c
index e01cc4dda..310fbf60f 100644
--- a/src/modules/systemlib/airspeed.c
+++ b/src/modules/systemlib/airspeed.c
@@ -42,7 +42,7 @@
 
 #include <stdio.h>
 #include <math.h>
-#include "conversions.h"
+#include <geo/geo.h>
 #include "airspeed.h"
 
 
@@ -95,17 +95,21 @@ float calc_true_airspeed_from_indicated(float speed_indicated, float pressure_am
 float calc_true_airspeed(float total_pressure, float static_pressure, float temperature_celsius)
 {
 	float density = get_air_density(static_pressure, temperature_celsius);
+
 	if (density < 0.0001f || !isfinite(density)) {
-	 density = CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C;
-//	 printf("[airspeed] Invalid air density, using density at sea level\n");
+		density = CONSTANTS_AIR_DENSITY_SEA_LEVEL_15C;
 	}
 
 	float pressure_difference = total_pressure - static_pressure;
 
-	if(pressure_difference > 0) {
+	if (pressure_difference > 0) {
 		return sqrtf((2.0f*(pressure_difference)) / density);
-	} else
-	{
+	} else {
 		return -sqrtf((2.0f*fabsf(pressure_difference)) / density);
 	}
 }
+
+float get_air_density(float static_pressure, float temperature_celsius)
+{
+	return static_pressure / (CONSTANTS_AIR_GAS_CONST * (temperature_celsius - CONSTANTS_ABSOLUTE_NULL_CELSIUS));
+}
diff --git a/src/modules/systemlib/airspeed.h b/src/modules/systemlib/airspeed.h
index def53f0c1..8dccaab9c 100644
--- a/src/modules/systemlib/airspeed.h
+++ b/src/modules/systemlib/airspeed.h
@@ -85,6 +85,14 @@
   */
  __EXPORT float calc_true_airspeed(float total_pressure, float static_pressure, float temperature_celsius);
 
+ /**
+ * 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
diff --git a/src/modules/systemlib/conversions.c b/src/modules/systemlib/conversions.c
index ac94252c5..9105d83cb 100644
--- a/src/modules/systemlib/conversions.c
+++ b/src/modules/systemlib/conversions.c
@@ -55,100 +55,3 @@ int16_t_from_bytes(uint8_t bytes[])
 
 	return u.w;
 }
-
-void rot2quat(const float R[9], float Q[4])
-{
-	float q0_2;
-	float q1_2;
-	float q2_2;
-	float q3_2;
-	int32_t idx;
-
-	/* conversion of rotation matrix to quaternion
-	 * choose the largest component to begin with */
-	q0_2 = (((1.0F + R[0]) + R[4]) + R[8]) / 4.0F;
-	q1_2 = (((1.0F + R[0]) - R[4]) - R[8]) / 4.0F;
-	q2_2 = (((1.0F - R[0]) + R[4]) - R[8]) / 4.0F;
-	q3_2 = (((1.0F - R[0]) - R[4]) + R[8]) / 4.0F;
-
-	idx = 0;
-
-	if (q0_2 < q1_2) {
-		q0_2 = q1_2;
-
-		idx = 1;
-	}
-
-	if (q0_2 < q2_2) {
-		q0_2 = q2_2;
-		idx = 2;
-	}
-
-	if (q0_2 < q3_2) {
-		q0_2 = q3_2;
-		idx = 3;
-	}
-
-	q0_2 = sqrtf(q0_2);
-
-	/* solve for the remaining three components */
-	if (idx == 0) {
-		q1_2 = q0_2;
-		q2_2 = (R[5] - R[7]) / 4.0F / q0_2;
-		q3_2 = (R[6] - R[2]) / 4.0F / q0_2;
-		q0_2 = (R[1] - R[3]) / 4.0F / q0_2;
-
-	} else if (idx == 1) {
-		q2_2 = q0_2;
-		q1_2 = (R[5] - R[7]) / 4.0F / q0_2;
-		q3_2 = (R[3] + R[1]) / 4.0F / q0_2;
-		q0_2 = (R[6] + R[2]) / 4.0F / q0_2;
-
-	} else if (idx == 2) {
-		q3_2 = q0_2;
-		q1_2 = (R[6] - R[2]) / 4.0F / q0_2;
-		q2_2 = (R[3] + R[1]) / 4.0F / q0_2;
-		q0_2 = (R[7] + R[5]) / 4.0F / q0_2;
-
-	} else {
-		q1_2 = (R[1] - R[3]) / 4.0F / q0_2;
-		q2_2 = (R[6] + R[2]) / 4.0F / q0_2;
-		q3_2 = (R[7] + R[5]) / 4.0F / q0_2;
-	}
-
-	/* return values */
-	Q[0] = q1_2;
-	Q[1] = q2_2;
-	Q[2] = q3_2;
-	Q[3] = q0_2;
-}
-
-void quat2rot(const float Q[4], float R[9])
-{
-	float q0_2;
-	float q1_2;
-	float q2_2;
-	float q3_2;
-
-	memset(&R[0], 0, 9U * sizeof(float));
-
-	q0_2 = Q[0] * Q[0];
-	q1_2 = Q[1] * Q[1];
-	q2_2 = Q[2] * Q[2];
-	q3_2 = Q[3] * Q[3];
-
-	R[0] = ((q0_2 + q1_2) - q2_2) - q3_2;
-	R[3] = 2.0F * (Q[1] * Q[2] - Q[0] * Q[3]);
-	R[6] = 2.0F * (Q[1] * Q[3] + Q[0] * Q[2]);
-	R[1] = 2.0F * (Q[1] * Q[2] + Q[0] * Q[3]);
-	R[4] = ((q0_2 + q2_2) - q1_2) - q3_2;
-	R[7] = 2.0F * (Q[2] * Q[3] - Q[0] * Q[1]);
-	R[2] = 2.0F * (Q[1] * Q[3] - Q[0] * Q[2]);
-	R[5] = 2.0F * (Q[2] * Q[3] + Q[0] * Q[1]);
-	R[8] = ((q0_2 + q3_2) - q1_2) - q2_2;
-}
-
-float get_air_density(float static_pressure, float temperature_celsius)
-{
-	return static_pressure / (CONSTANTS_AIR_GAS_CONST * (temperature_celsius - CONSTANTS_ABSOLUTE_NULL_CELSIUS));
-}
diff --git a/src/modules/systemlib/conversions.h b/src/modules/systemlib/conversions.h
index 064426f21..dc383e770 100644
--- a/src/modules/systemlib/conversions.h
+++ b/src/modules/systemlib/conversions.h
@@ -43,7 +43,6 @@
 #define CONVERSIONS_H_
 #include <float.h>
 #include <stdint.h>
-#include <systemlib/geo/geo.h>
 
 __BEGIN_DECLS
 
@@ -57,34 +56,6 @@ __BEGIN_DECLS
  */
 __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_ */
diff --git a/src/modules/systemlib/geo/geo.c b/src/modules/systemlib/geo/geo.c
deleted file mode 100644
index 6463e6489..000000000
--- a/src/modules/systemlib/geo/geo.c
+++ /dev/null
@@ -1,438 +0,0 @@
-/****************************************************************************
- *
- *   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 <nuttx/config.h>
-#include <unistd.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <math.h>
-#include <stdbool.h>
-
-
-/* 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;
-
-__EXPORT 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;
-
-}
-
-__EXPORT 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);
-}
-
-__EXPORT 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;
-
-}
-
-
-__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 / 180.0d * M_PI;
-	double lon_now_rad = lon_now / 180.0d * M_PI;
-	double lat_next_rad = lat_next / 180.0d * M_PI;
-	double lon_next_rad = lon_next / 180.0d * 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 / 2.0d) * sin(d_lat / 2.0d) + sin(d_lon / 2.0d) * sin(d_lon / 2.0d) * cos(lat_now_rad) * cos(lat_next_rad);
-	double c = 2.0d * atan2(sqrt(a), sqrt(1.0d - a));
-
-	const double radius_earth = 6371000.0d;
-	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 * M_DEG_TO_RAD;
-	double lon_now_rad = lon_now * M_DEG_TO_RAD;
-	double lat_next_rad = lat_next * M_DEG_TO_RAD;
-	double lon_next_rad = lon_next * M_DEG_TO_RAD;
-
-	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));
-
-	theta = _wrap_pi(theta);
-
-	return theta;
-}
-
-// Additional functions - @author Doug Weibel <douglas.weibel@colorado.edu>
-
-__EXPORT int get_distance_to_line(struct crosstrack_error_s * crosstrack_error, double lat_now, double lon_now, double lat_start, double lon_start, double lat_end, double lon_end)
-{
-// This function returns the distance to the nearest point on the track line.  Distance is positive if current
-// position is right of the track and negative if left of the track as seen from a point on the track line
-// headed towards the end point.
-
-	float dist_to_end;
-	float bearing_end;
-	float bearing_track;
-	float bearing_diff;
-
-	int return_value = ERROR;	// Set error flag, cleared when valid result calculated.
-	crosstrack_error->past_end = false;
-	crosstrack_error->distance = 0.0f;
-	crosstrack_error->bearing = 0.0f;
-
-	// Return error if arguments are bad
-	if (lat_now == 0.0d || lon_now == 0.0d || lat_start == 0.0d || lon_start == 0.0d || lat_end == 0.0d || lon_end == 0.0d) return return_value;
-
-	bearing_end = get_bearing_to_next_waypoint(lat_now, lon_now, lat_end, lon_end);
-	bearing_track = get_bearing_to_next_waypoint(lat_start, lon_start, lat_end, lon_end);
-	bearing_diff = bearing_track - bearing_end;
-	bearing_diff = _wrap_pi(bearing_diff);
-
-	// Return past_end = true if past end point of line
-	if (bearing_diff > M_PI_2_F || bearing_diff < -M_PI_2_F) {
-		crosstrack_error->past_end = true;
-		return_value = OK;
-		return return_value;
-	}
-
-	dist_to_end = get_distance_to_next_waypoint(lat_now, lon_now, lat_end, lon_end);
-	crosstrack_error->distance = (dist_to_end) * sin(bearing_diff);
-
-	if (sin(bearing_diff) >= 0) {
-		crosstrack_error->bearing = _wrap_pi(bearing_track - M_PI_2_F);
-
-	} else {
-		crosstrack_error->bearing = _wrap_pi(bearing_track + M_PI_2_F);
-	}
-
-	return_value = OK;
-
-	return return_value;
-
-}
-
-
-__EXPORT int get_distance_to_arc(struct crosstrack_error_s * crosstrack_error, double lat_now, double lon_now, double lat_center, double lon_center,
-		float radius, float arc_start_bearing, float arc_sweep)
-{
-	// This function returns the distance to the nearest point on the track arc.  Distance is positive if current
-	// position is right of the arc and negative if left of the arc as seen from the closest point on the arc and
-	// headed towards the end point.
-
-	// Determine if the current position is inside or outside the sector between the line from the center
-	// to the arc start and the line from the center to the arc end
-	float	bearing_sector_start;
-	float	bearing_sector_end;
-	float	bearing_now = get_bearing_to_next_waypoint(lat_now, lon_now, lat_center, lon_center);
-	bool	in_sector;
-
-	int return_value = ERROR;		// Set error flag, cleared when valid result calculated.
-	crosstrack_error->past_end = false;
-	crosstrack_error->distance = 0.0f;
-	crosstrack_error->bearing = 0.0f;
-
-	// Return error if arguments are bad
-	if (lat_now == 0.0d || lon_now == 0.0d || lat_center == 0.0d || lon_center == 0.0d || radius == 0.0d) return return_value;
-
-
-	if (arc_sweep >= 0) {
-		bearing_sector_start = arc_start_bearing;
-		bearing_sector_end = arc_start_bearing + arc_sweep;
-
-		if (bearing_sector_end > 2.0f * M_PI_F) bearing_sector_end -= M_TWOPI_F;
-
-	} else {
-		bearing_sector_end = arc_start_bearing;
-		bearing_sector_start = arc_start_bearing - arc_sweep;
-
-		if (bearing_sector_start < 0.0f) bearing_sector_start += M_TWOPI_F;
-	}
-
-	in_sector = false;
-
-	// Case where sector does not span zero
-	if (bearing_sector_end >= bearing_sector_start && bearing_now >= bearing_sector_start && bearing_now <= bearing_sector_end) in_sector = true;
-
-	// Case where sector does span zero
-	if (bearing_sector_end < bearing_sector_start && (bearing_now > bearing_sector_start || bearing_now < bearing_sector_end)) in_sector = true;
-
-	// If in the sector then calculate distance and bearing to closest point
-	if (in_sector) {
-		crosstrack_error->past_end = false;
-		float dist_to_center = get_distance_to_next_waypoint(lat_now, lon_now, lat_center, lon_center);
-
-		if (dist_to_center <= radius) {
-			crosstrack_error->distance = radius - dist_to_center;
-			crosstrack_error->bearing = bearing_now + M_PI_F;
-
-		} else {
-			crosstrack_error->distance = dist_to_center - radius;
-			crosstrack_error->bearing = bearing_now;
-		}
-
-		// If out of the sector then calculate dist and bearing to start or end point
-
-	} else {
-
-		// Use the approximation  that 111,111 meters in the y direction is 1 degree (of latitude)
-		// and 111,111 * cos(latitude) meters in the x direction is 1 degree (of longitude) to
-		// calculate the position of the start and end points.  We should not be doing this often
-		// as this function generally will not be called repeatedly when we are out of the sector.
-
-		// TO DO - this is messed up and won't compile
-		float start_disp_x = radius * sin(arc_start_bearing);
-		float start_disp_y = radius * cos(arc_start_bearing);
-		float end_disp_x = radius * sin(_wrapPI(arc_start_bearing + arc_sweep));
-		float end_disp_y = radius * cos(_wrapPI(arc_start_bearing + arc_sweep));
-		float lon_start = lon_now + start_disp_x / 111111.0d;
-		float lat_start = lat_now + start_disp_y * cos(lat_now) / 111111.0d;
-		float lon_end = lon_now + end_disp_x / 111111.0d;
-		float lat_end = lat_now + end_disp_y * cos(lat_now) / 111111.0d;
-		float dist_to_start = get_distance_to_next_waypoint(lat_now, lon_now, lat_start, lon_start);
-		float dist_to_end = get_distance_to_next_waypoint(lat_now, lon_now, lat_end, lon_end);
-
-
-		if (dist_to_start < dist_to_end) {
-			crosstrack_error->distance = dist_to_start;
-			crosstrack_error->bearing = get_bearing_to_next_waypoint(lat_now, lon_now, lat_start, lon_start);
-
-		} else {
-			crosstrack_error->past_end = true;
-			crosstrack_error->distance = dist_to_end;
-			crosstrack_error->bearing = get_bearing_to_next_waypoint(lat_now, lon_now, lat_end, lon_end);
-		}
-
-	}
-
-	crosstrack_error->bearing = _wrapPI(crosstrack_error->bearing);
-	return_value = OK;
-	return return_value;
-}
-
-__EXPORT float _wrap_pi(float bearing)
-{
-	/* value is inf or NaN */
-	if (!isfinite(bearing) || bearing == 0) {
-		return bearing;
-	}
-
-	int c = 0;
-
-	while (bearing > M_PI_F && c < 30) {
-		bearing -= M_TWOPI_F;
-		c++;
-	}
-
-	c = 0;
-
-	while (bearing <=  -M_PI_F && c < 30) {
-		bearing += M_TWOPI_F;
-		c++;
-	}
-
-	return bearing;
-}
-
-__EXPORT float _wrap_2pi(float bearing)
-{
-	/* value is inf or NaN */
-	if (!isfinite(bearing)) {
-		return bearing;
-	}
-
-	while (bearing >= M_TWOPI_F) {
-		bearing = bearing - M_TWOPI_F;
-	}
-
-	while (bearing <  0.0f) {
-		bearing = bearing + M_TWOPI_F;
-	}
-
-	return bearing;
-}
-
-__EXPORT float _wrap_180(float bearing)
-{
-	/* value is inf or NaN */
-	if (!isfinite(bearing)) {
-		return bearing;
-	}
-
-	while (bearing > 180.0f) {
-		bearing = bearing - 360.0f;
-	}
-
-	while (bearing <=  -180.0f) {
-		bearing = bearing + 360.0f;
-	}
-
-	return bearing;
-}
-
-__EXPORT float _wrap_360(float bearing)
-{
-	/* value is inf or NaN */
-	if (!isfinite(bearing)) {
-		return bearing;
-	}
-
-	while (bearing >= 360.0f) {
-		bearing = bearing - 360.0f;
-	}
-
-	while (bearing <  0.0f) {
-		bearing = bearing + 360.0f;
-	}
-
-	return bearing;
-}
-
-
diff --git a/src/modules/systemlib/geo/geo.h b/src/modules/systemlib/geo/geo.h
deleted file mode 100644
index dadec51ec..000000000
--- a/src/modules/systemlib/geo/geo.h
+++ /dev/null
@@ -1,129 +0,0 @@
-/****************************************************************************
- *
- *   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>
- * Additional functions - @author Doug Weibel <douglas.weibel@colorado.edu>
- */
-
-#pragma once
-
-__BEGIN_DECLS
-
-#include <stdbool.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			*/
-#define CONSTANTS_RADIUS_OF_EARTH			6371000			/* meters (m)		*/
-
-/* compatibility aliases */
-#define RADIUS_OF_EARTH		CONSTANTS_RADIUS_OF_EARTH
-#define GRAVITY_MSS		CONSTANTS_ONE_G
-
-// XXX remove
-struct crosstrack_error_s {
-	bool past_end;		// Flag indicating we are past the end of the line/arc segment
-	float distance;		// Distance in meters to closest point on line/arc
-	float bearing;		// Bearing in radians to closest point on line/arc
-} ;
-
-/**
- * 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°)
- */
-__EXPORT void map_projection_init(double lat_0, double lon_0);
-
-/**
- * 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°)
- */
-__EXPORT void map_projection_project(double lat, double lon, float *x, float *y);
-
-/**
- * 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°)
- */
-__EXPORT void map_projection_reproject(float x, float y, double *lat, double *lon);
-
-/**
- * Returns the distance to the next waypoint in meters.
- *
- * @param lat_now current position in degrees (47.1234567°, not 471234567°)
- * @param lon_now current position in degrees (8.1234567°, not 81234567°)
- * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
- * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
- */
-__EXPORT float get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);
-
-/**
- * Returns the bearing to the next waypoint in radians.
- *
- * @param lat_now current position in degrees (47.1234567°, not 471234567°)
- * @param lon_now current position in degrees (8.1234567°, not 81234567°)
- * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
- * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
- */
-__EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);
-
-__EXPORT int get_distance_to_line(struct crosstrack_error_s * crosstrack_error, double lat_now, double lon_now, double lat_start, double lon_start, double lat_end, double lon_end);
-
-__EXPORT int get_distance_to_arc(struct crosstrack_error_s * crosstrack_error, double lat_now, double lon_now, double lat_center, double lon_center,
-		float radius, float arc_start_bearing, float arc_sweep);
-
-__EXPORT float _wrap_180(float bearing);
-__EXPORT float _wrap_360(float bearing);
-__EXPORT float _wrap_pi(float bearing);
-__EXPORT float _wrap_2pi(float bearing);
-
-__END_DECLS
diff --git a/src/modules/systemlib/mavlink_log.c b/src/modules/systemlib/mavlink_log.c
new file mode 100644
index 000000000..f321f9ceb
--- /dev/null
+++ b/src/modules/systemlib/mavlink_log.c
@@ -0,0 +1,128 @@
+/****************************************************************************
+ *
+ *   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 mavlink_log.c
+ * MAVLink text logging.
+ *
+ * @author Lorenz Meier <lm@inf.ethz.ch>
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <mavlink/mavlink_log.h>
+
+__EXPORT void mavlink_logbuffer_init(struct mavlink_logbuffer *lb, int size)
+{
+	lb->size  = size;
+	lb->start = 0;
+	lb->count = 0;
+	lb->elems = calloc(lb->size, sizeof(struct mavlink_logmessage));
+}
+
+__EXPORT void mavlink_logbuffer_destroy(struct mavlink_logbuffer *lb)
+{
+	lb->size  = 0;
+	lb->start = 0;
+	lb->count = 0;
+	free(lb->elems);
+}
+
+__EXPORT int mavlink_logbuffer_is_full(struct mavlink_logbuffer *lb)
+{
+	return lb->count == (int)lb->size;
+}
+
+__EXPORT int mavlink_logbuffer_is_empty(struct mavlink_logbuffer *lb)
+{
+	return lb->count == 0;
+}
+
+__EXPORT void mavlink_logbuffer_write(struct mavlink_logbuffer *lb, const struct mavlink_logmessage *elem)
+{
+	int end = (lb->start + lb->count) % lb->size;
+	memcpy(&(lb->elems[end]), elem, sizeof(struct mavlink_logmessage));
+
+	if (mavlink_logbuffer_is_full(lb)) {
+		lb->start = (lb->start + 1) % lb->size; /* full, overwrite */
+
+	} else {
+		++lb->count;
+	}
+}
+
+__EXPORT int mavlink_logbuffer_read(struct mavlink_logbuffer *lb, struct mavlink_logmessage *elem)
+{
+	if (!mavlink_logbuffer_is_empty(lb)) {
+		memcpy(elem, &(lb->elems[lb->start]), sizeof(struct mavlink_logmessage));
+		lb->start = (lb->start + 1) % lb->size;
+		--lb->count;
+
+		return 0;
+
+	} else {
+		return 1;
+	}
+}
+
+__EXPORT void mavlink_logbuffer_vasprintf(struct mavlink_logbuffer *lb, int severity, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	int end = (lb->start + lb->count) % lb->size;
+	lb->elems[end].severity = severity;
+	vsnprintf(lb->elems[end].text, sizeof(lb->elems[0].text), fmt, ap);
+	va_end(ap);
+
+	/* increase count */
+	if (mavlink_logbuffer_is_full(lb)) {
+		lb->start = (lb->start + 1) % lb->size; /* full, overwrite */
+
+	} else {
+		++lb->count;
+	}
+}
+
+__EXPORT void mavlink_vasprintf(int _fd, int severity, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	char text[MAVLINK_LOG_MAXLEN + 1];
+	vsnprintf(text, sizeof(text), fmt, ap);
+	va_end(ap);
+	ioctl(_fd, severity, (unsigned long)&text[0]);
+}
diff --git a/src/modules/systemlib/mixer/mixer.cpp b/src/modules/systemlib/mixer/mixer.cpp
index df0dfe838..cce46bf5f 100644
--- a/src/modules/systemlib/mixer/mixer.cpp
+++ b/src/modules/systemlib/mixer/mixer.cpp
@@ -50,6 +50,8 @@
 #include <stdio.h>
 #include <math.h>
 #include <unistd.h>
+#include <ctype.h>
+#include <systemlib/err.h>
 
 #include "mixer.h"
 
@@ -114,6 +116,33 @@ Mixer::scale_check(struct mixer_scaler_s &scaler)
 	return 0;
 }
 
+const char *
+Mixer::findtag(const char *buf, unsigned &buflen, char tag)
+{
+	while (buflen >= 2) {
+		if ((buf[0] == tag) && (buf[1] == ':'))
+			return buf;
+		buf++;
+		buflen--;
+	}
+	return nullptr;
+}
+
+const char *
+Mixer::skipline(const char *buf, unsigned &buflen)
+{
+	const char *p;
+
+	/* if we can find a CR or NL in the buffer, skip up to it */
+	if ((p = (const char *)memchr(buf, '\r', buflen)) || (p = (const char *)memchr(buf, '\n', buflen))) {
+		/* skip up to it AND one beyond - could be on the NUL symbol now */
+		buflen -= (p - buf) + 1;
+		return p + 1;
+	}
+
+	return nullptr;
+}
+
 /****************************************************************************/
 
 NullMixer::NullMixer() :
@@ -142,6 +171,22 @@ NullMixer *
 NullMixer::from_text(const char *buf, unsigned &buflen)
 {
 	NullMixer *nm = nullptr;
+	const char *end = buf + buflen;
+
+	/* enforce that the mixer ends with space or a new line */
+	for (int i = buflen - 1; i >= 0; i--) {
+		if (buf[i] == '\0')
+			continue;
+
+		/* require a space or newline at the end of the buffer, fail on printable chars */
+		if (buf[i] == ' ' || buf[i] == '\n' || buf[i] == '\r') {
+			/* found a line ending or space, so no split symbols / numbers. good. */
+			break;
+		} else {
+			return nm;
+		}
+
+	}
 
 	if ((buflen >= 2) && (buf[0] == 'Z') && (buf[1] == ':')) {
 		nm = new NullMixer;
diff --git a/src/modules/systemlib/mixer/mixer.h b/src/modules/systemlib/mixer/mixer.h
index bbfa130a9..1c889a811 100644
--- a/src/modules/systemlib/mixer/mixer.h
+++ b/src/modules/systemlib/mixer/mixer.h
@@ -128,7 +128,9 @@
 #ifndef _SYSTEMLIB_MIXER_MIXER_H
 #define _SYSTEMLIB_MIXER_MIXER_H value
 
+#include <nuttx/config.h>
 #include "drivers/drv_mixer.h"
+#include "mixer_load.h"
 
 /**
  * Abstract class defining a mixer mixing zero or more inputs to
@@ -210,6 +212,24 @@ protected:
 	 */
 	static int			scale_check(struct mixer_scaler_s &scaler);
 
+	/**
+	 * Find a tag
+	 *
+	 * @param buf			The buffer to operate on.
+	 * @param buflen		length of the buffer.
+	 * @param tag			character to search for.
+	 */
+	static const char *		findtag(const char *buf, unsigned &buflen, char tag);
+
+	/**
+	 * Skip a line
+	 *
+	 * @param buf			The buffer to operate on.
+	 * @param buflen		length of the buffer.
+	 * @return			0 / OK if a line could be skipped, 1 else
+	 */
+	static const char *		skipline(const char *buf, unsigned &buflen);
+
 private:
 };
 
@@ -239,6 +259,11 @@ public:
 	void				reset();
 
 	/**
+	 * Count the mixers in the group.
+	 */
+	unsigned			count();
+
+	/**
 	 * Adds mixers to the group based on a text description in a buffer.
 	 *
 	 * Mixer definitions begin with a single capital letter and a colon.
@@ -424,6 +449,7 @@ public:
 		HEX_PLUS,	/**< hex in + configuration */
 		OCTA_X,
 		OCTA_PLUS,
+		OCTA_COX,
 
 		MAX_GEOMETRY
 	};
diff --git a/src/modules/systemlib/mixer/mixer_group.cpp b/src/modules/systemlib/mixer/mixer_group.cpp
index 1dbc512cd..3ed99fba0 100644
--- a/src/modules/systemlib/mixer/mixer_group.cpp
+++ b/src/modules/systemlib/mixer/mixer_group.cpp
@@ -111,6 +111,20 @@ MixerGroup::mix(float *outputs, unsigned space)
 	return index;
 }
 
+unsigned
+MixerGroup::count()
+{
+	Mixer	*mixer = _first;
+	unsigned index = 0;
+
+	while ((mixer != nullptr)) {
+		mixer = mixer->_next;
+		index++;
+	}
+
+	return index;
+}
+
 void
 MixerGroup::groups_required(uint32_t &groups)
 {
@@ -170,6 +184,7 @@ MixerGroup::load_from_buf(const char *buf, unsigned &buflen)
 
 			/* only adjust buflen if parsing was successful */
 			buflen = resid;
+			debug("SUCCESS - buflen: %d", buflen);
 		} else {
 
 			/*
diff --git a/src/modules/systemlib/mixer/mixer_load.c b/src/modules/systemlib/mixer/mixer_load.c
new file mode 100644
index 000000000..a55ddf8a3
--- /dev/null
+++ b/src/modules/systemlib/mixer/mixer_load.c
@@ -0,0 +1,100 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. 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 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 mixer_load.c
+ *
+ * Programmable multi-channel mixer library.
+ */
+
+#include <nuttx/config.h>
+#include <string.h>
+#include <stdio.h>
+#include <ctype.h>
+
+#include "mixer_load.h"
+
+int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
+{
+	FILE		*fp;
+	char		line[120];
+
+	/* open the mixer definition file */
+	fp = fopen(fname, "r");
+	if (fp == NULL) {
+		return 1;
+	}
+
+	/* read valid lines from the file into a buffer */
+	buf[0] = '\0';
+	for (;;) {
+
+		/* get a line, bail on error/EOF */
+		line[0] = '\0';
+		if (fgets(line, sizeof(line), fp) == NULL)
+			break;
+
+		/* if the line doesn't look like a mixer definition line, skip it */
+		if ((strlen(line) < 2) || !isupper(line[0]) || (line[1] != ':'))
+			continue;
+
+		/* compact whitespace in the buffer */
+		char *t, *f;
+		for (f = line; *f != '\0'; f++) {
+			/* scan for space characters */
+			if (*f == ' ') {
+				/* look for additional spaces */
+				t = f + 1;
+				while (*t == ' ')
+					t++;
+				if (*t == '\0') {
+					/* strip trailing whitespace */
+					*f = '\0';
+				} else if (t > (f + 1)) {
+					memmove(f + 1, t, strlen(t) + 1);
+				}
+			}
+		}
+
+		/* if the line is too long to fit in the buffer, bail */
+		if ((strlen(line) + strlen(buf) + 1) >= maxlen) {
+			return 1;
+		}
+
+		/* add the line to the buffer */
+		strcat(buf, line);
+	}
+
+	return 0;
+}
+
diff --git a/src/modules/systemlib/mixer/mixer_load.h b/src/modules/systemlib/mixer/mixer_load.h
new file mode 100644
index 000000000..4b7091d5b
--- /dev/null
+++ b/src/modules/systemlib/mixer/mixer_load.h
@@ -0,0 +1,51 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. 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 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 mixer_load.h
+ *
+ */
+
+
+#ifndef _SYSTEMLIB_MIXER_LOAD_H
+#define _SYSTEMLIB_MIXER_LOAD_H value
+
+#include <nuttx/config.h>
+
+__BEGIN_DECLS
+
+__EXPORT int load_mixer_file(const char *fname, char *buf, unsigned maxlen);
+
+__END_DECLS
+
+#endif
diff --git a/src/modules/systemlib/mixer/mixer_multirotor.cpp b/src/modules/systemlib/mixer/mixer_multirotor.cpp
index 8ded0b05c..bf77795d5 100644
--- a/src/modules/systemlib/mixer/mixer_multirotor.cpp
+++ b/src/modules/systemlib/mixer/mixer_multirotor.cpp
@@ -130,7 +130,17 @@ const MultirotorMixer::Rotor _config_octa_plus[] = {
 	{  1.000000,  0.000000, -1.00 },
 	{ -1.000000,  0.000000, -1.00 },
 };
-const MultirotorMixer::Rotor *_config_index[MultirotorMixer::Geometry::MAX_GEOMETRY] = {
+const MultirotorMixer::Rotor _config_octa_cox[] = {
+	{ -0.707107,  0.707107,  1.00 },
+	{  0.707107,  0.707107, -1.00 },
+	{  0.707107, -0.707107,  1.00 },
+	{ -0.707107, -0.707107, -1.00 },
+	{  0.707107,  0.707107,  1.00 },
+	{ -0.707107,  0.707107, -1.00 },
+	{ -0.707107, -0.707107,  1.00 },
+	{  0.707107, -0.707107, -1.00 },
+};
+const MultirotorMixer::Rotor *_config_index[MultirotorMixer::MAX_GEOMETRY] = {
 	&_config_quad_x[0],
 	&_config_quad_plus[0],
 	&_config_quad_v[0],
@@ -139,8 +149,9 @@ const MultirotorMixer::Rotor *_config_index[MultirotorMixer::Geometry::MAX_GEOME
 	&_config_hex_plus[0],
 	&_config_octa_x[0],
 	&_config_octa_plus[0],
+	&_config_octa_cox[0],
 };
-const unsigned _config_rotor_count[MultirotorMixer::Geometry::MAX_GEOMETRY] = {
+const unsigned _config_rotor_count[MultirotorMixer::MAX_GEOMETRY] = {
 	4, /* quad_x */
 	4, /* quad_plus */
 	4, /* quad_v */
@@ -149,6 +160,7 @@ const unsigned _config_rotor_count[MultirotorMixer::Geometry::MAX_GEOMETRY] = {
 	6, /* hex_plus */
 	8, /* octa_x */
 	8, /* octa_plus */
+	8, /* octa_cox */
 };
 
 }
@@ -181,6 +193,23 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 	char geomname[8];
 	int s[4];
 	int used;
+	const char *end = buf + buflen;
+
+	/* enforce that the mixer ends with space or a new line */
+	for (int i = buflen - 1; i >= 0; i--) {
+		if (buf[i] == '\0')
+			continue;
+
+		/* require a space or newline at the end of the buffer, fail on printable chars */
+		if (buf[i] == ' ' || buf[i] == '\n' || buf[i] == '\r') {
+			/* found a line ending or space, so no split symbols / numbers. good. */
+			break;
+		} else {
+			debug("simple parser rejected: No newline / space at end of buf. (#%d/%d: 0x%02x)", i, buflen-1, buf[i]);
+			return nullptr;
+		}
+
+	}
 
 	if (sscanf(buf, "R: %s %d %d %d %d%n", geomname, &s[0], &s[1], &s[2], &s[3], &used) != 5) {
 		debug("multirotor parse failed on '%s'", buf);
@@ -188,11 +217,17 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 	}
 
 	if (used > (int)buflen) {
-		debug("multirotor spec used %d of %u", used, buflen);
+		debug("OVERFLOW: multirotor spec used %d of %u", used, buflen);
+		return nullptr;
+	}
+
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
 		return nullptr;
 	}
 
-	buflen -= used;
+	debug("remaining in buf: %d, first char: %c", buflen, buf[0]);
 
 	if (!strcmp(geomname, "4+")) {
 		geometry = MultirotorMixer::QUAD_PLUS;
@@ -217,6 +252,9 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 
 	} else if (!strcmp(geomname, "8x")) {
 		geometry = MultirotorMixer::OCTA_X;
+		
+	} else if (!strcmp(geomname, "8c")) {
+		geometry = MultirotorMixer::OCTA_COX;
 
 	} else {
 		debug("unrecognised geometry '%s'", geomname);
diff --git a/src/modules/systemlib/mixer/mixer_simple.cpp b/src/modules/systemlib/mixer/mixer_simple.cpp
index 07dc5f37f..c3985b5de 100644
--- a/src/modules/systemlib/mixer/mixer_simple.cpp
+++ b/src/modules/systemlib/mixer/mixer_simple.cpp
@@ -71,44 +71,30 @@ SimpleMixer::~SimpleMixer()
 		free(_info);
 }
 
-static const char *
-findtag(const char *buf, unsigned &buflen, char tag)
-{
-	while (buflen >= 2) {
-		if ((buf[0] == tag) && (buf[1] == ':'))
-			return buf;
-		buf++;
-		buflen--;
-	}
-	return nullptr;
-}
-
-static void
-skipline(const char *buf, unsigned &buflen)
-{
-	const char *p;
-
-	/* if we can find a CR or NL in the buffer, skip up to it */
-	if ((p = (const char *)memchr(buf, '\r', buflen)) || (p = (const char *)memchr(buf, '\n', buflen)))
-		buflen -= (p - buf);
-}
-
 int
 SimpleMixer::parse_output_scaler(const char *buf, unsigned &buflen, mixer_scaler_s &scaler)
 {
 	int ret;
 	int s[5];
+	int n = -1;
 	
 	buf = findtag(buf, buflen, 'O');
-	if ((buf == nullptr) || (buflen < 12))
+	if ((buf == nullptr) || (buflen < 12)) {
+		debug("output parser failed finding tag, ret: '%s'", buf);
 		return -1;
+	}
 
-	if ((ret = sscanf(buf, "O: %d %d %d %d %d",
-			  &s[0], &s[1], &s[2], &s[3], &s[4])) != 5) {
-		debug("scaler parse failed on '%s' (got %d)", buf, ret);
+	if ((ret = sscanf(buf, "O: %d %d %d %d %d %n",
+			  &s[0], &s[1], &s[2], &s[3], &s[4], &n)) != 5) {
+		debug("out scaler parse failed on '%s' (got %d, consumed %d)", buf, ret, n);
+		return -1;
+	}
+
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
 		return -1;
 	}
-	skipline(buf, buflen);
 
 	scaler.negative_scale	= s[0] / 10000.0f;
 	scaler.positive_scale	= s[1] / 10000.0f;
@@ -126,15 +112,22 @@ SimpleMixer::parse_control_scaler(const char *buf, unsigned &buflen, mixer_scale
 	int s[5];
 
 	buf = findtag(buf, buflen, 'S');
-	if ((buf == nullptr) || (buflen < 16))
+	if ((buf == nullptr) || (buflen < 16)) {
+		debug("control parser failed finding tag, ret: '%s'", buf);
 		return -1;
+	}
 
 	if (sscanf(buf, "S: %u %u %d %d %d %d %d",
 		   &u[0], &u[1], &s[0], &s[1], &s[2], &s[3], &s[4]) != 7) {
 		debug("control parse failed on '%s'", buf);
 		return -1;
 	}
-	skipline(buf, buflen);
+
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		return -1;
+	}
 
 	control_group		= u[0];
 	control_index		= u[1];
@@ -162,7 +155,11 @@ SimpleMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, c
 		goto out;
 	}
 
-	buflen -= used;
+	buf = skipline(buf, buflen);
+	if (buf == nullptr) {
+		debug("no line ending, line is incomplete");
+		goto out;
+	}
 
 	mixinfo = (mixer_simple_s *)malloc(MIXER_SIMPLE_SIZE(inputs));
 
@@ -173,22 +170,27 @@ SimpleMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, c
 
 	mixinfo->control_count = inputs;
 
-	if (parse_output_scaler(end - buflen, buflen, mixinfo->output_scaler))
+	if (parse_output_scaler(end - buflen, buflen, mixinfo->output_scaler)) {
+		debug("simple mixer parser failed parsing out scaler tag, ret: '%s'", buf);
 		goto out;
+	}
 
 	for (unsigned i = 0; i < inputs; i++) {
 		if (parse_control_scaler(end - buflen, buflen,
 					 mixinfo->controls[i].scaler,
 					 mixinfo->controls[i].control_group,
-					 mixinfo->controls[i].control_index))
+					 mixinfo->controls[i].control_index)) {
+			debug("simple mixer parser failed parsing ctrl scaler tag, ret: '%s'", buf);
 			goto out;
+		}
+
 	}
 
 	sm = new SimpleMixer(control_cb, cb_handle, mixinfo);
 
 	if (sm != nullptr) {
 		mixinfo = nullptr;
-		debug("loaded mixer with %d inputs", inputs);
+		debug("loaded mixer with %d input(s)", inputs);
 
 	} else {
 		debug("could not allocate memory for mixer");
diff --git a/src/modules/systemlib/mixer/module.mk b/src/modules/systemlib/mixer/module.mk
index 4d45e1c50..fc7485e20 100644
--- a/src/modules/systemlib/mixer/module.mk
+++ b/src/modules/systemlib/mixer/module.mk
@@ -39,4 +39,5 @@ LIBNAME	= mixerlib
 SRCS		= mixer.cpp \
 		  mixer_group.cpp \
 		  mixer_multirotor.cpp \
-		  mixer_simple.cpp
+		  mixer_simple.cpp \
+		  mixer_load.c
diff --git a/src/modules/systemlib/mixer/multi_tables b/src/modules/systemlib/mixer/multi_tables
index 683c63040..050bf2f47 100755
--- a/src/modules/systemlib/mixer/multi_tables
+++ b/src/modules/systemlib/mixer/multi_tables
@@ -74,7 +74,18 @@ set octa_plus {
 	  90 CW
 }
 
-set tables {quad_x quad_plus quad_v quad_wide hex_x hex_plus octa_x octa_plus}
+set octa_cox {
+	  45 CCW
+	 -45 CW
+	-135 CCW
+	 135 CW
+	 -45 CCW
+	  45 CW
+	 135 CCW
+	-135 CW
+}
+
+set tables {quad_x quad_plus quad_v quad_wide hex_x hex_plus octa_x octa_plus octa_cox}
 
 proc factors {a d} { puts [format "\t{ %9.6f, %9.6f, %5.2f }," [rcos [expr $a + 90]] [rcos $a] [expr -$d]]}
 
diff --git a/src/modules/systemlib/module.mk b/src/modules/systemlib/module.mk
index b470c1227..843cda722 100644
--- a/src/modules/systemlib/module.mk
+++ b/src/modules/systemlib/module.mk
@@ -45,7 +45,8 @@ SRCS		 = err.c \
 		   getopt_long.c \
 		   up_cxxinitialize.c \
 		   pid/pid.c \
-		   geo/geo.c \
 		   systemlib.c \
 		   airspeed.c \
-		   system_params.c
+		   system_params.c \
+		   mavlink_log.c \
+		   rc_check.c
diff --git a/src/modules/systemlib/param/param.c b/src/modules/systemlib/param/param.c
index 69a9bdf9b..398657dd7 100644
--- a/src/modules/systemlib/param/param.c
+++ b/src/modules/systemlib/param/param.c
@@ -48,6 +48,7 @@
 #include <unistd.h>
 #include <systemlib/err.h>
 #include <errno.h>
+#include <semaphore.h>
 
 #include <sys/stat.h>
 
@@ -95,18 +96,20 @@ ORB_DEFINE(parameter_update, struct parameter_update_s);
 /** parameter update topic handle */
 static orb_advert_t param_topic = -1;
 
+static sem_t param_sem = { .semcount = 1 };
+
 /** lock the parameter store */
 static void
 param_lock(void)
 {
-	/* XXX */
+	//do {} while (sem_wait(&param_sem) != 0);
 }
 
 /** unlock the parameter store */
 static void
 param_unlock(void)
 {
-	/* XXX */
+	//sem_post(&param_sem);
 }
 
 /** assert that the parameter store is locked */
@@ -505,27 +508,63 @@ param_get_default_file(void)
 int
 param_save_default(void)
 {
-	/* delete the file in case it exists */
-	unlink(param_get_default_file());
+	int res;
+	int fd;
 
-	/* create the file */
-	int fd = open(param_get_default_file(), O_WRONLY | O_CREAT | O_EXCL);
+	const char *filename = param_get_default_file();
+	const char *filename_tmp = malloc(strlen(filename) + 5);
+	sprintf(filename_tmp, "%s.tmp", filename);
 
-	if (fd < 0) {
-		warn("opening '%s' for writing failed", param_get_default_file());
-		return -1;
+	/* delete temp file if exist */
+	res = unlink(filename_tmp);
+
+	if (res != OK && errno == ENOENT)
+		res = OK;
+
+	if (res != OK)
+		warn("failed to delete temp file: %s", filename_tmp);
+
+	if (res == OK) {
+		/* write parameters to temp file */
+		fd = open(filename_tmp, O_WRONLY | O_CREAT | O_EXCL);
+
+		if (fd < 0) {
+			warn("failed to open temp file: %s", filename_tmp);
+			res = ERROR;
+		}
+
+		if (res == OK) {
+			res = param_export(fd, false);
+
+			if (res != OK)
+				warnx("failed to write parameters to file: %s", filename_tmp);
+		}
+
+		close(fd);
 	}
 
-	int result = param_export(fd, false);
-	close(fd);
+	if (res == OK) {
+		/* delete parameters file */
+		res = unlink(filename);
 
-	if (result != 0) {
-		warn("error exporting parameters to '%s'", param_get_default_file());
-		unlink(param_get_default_file());
-		return -2;
+		if (res != OK && errno == ENOENT)
+			res = OK;
+
+		if (res != OK)
+			warn("failed to delete parameters file: %s", filename);
 	}
 
-	return 0;
+	if (res == OK) {
+		/* rename temp file to parameters */
+		res = rename(filename_tmp, filename);
+
+		if (res != OK)
+			warn("failed to rename %s to %s", filename_tmp, filename);
+	}
+
+	free(filename_tmp);
+
+	return res;
 }
 
 /**
diff --git a/src/modules/systemlib/perf_counter.c b/src/modules/systemlib/perf_counter.c
index 3c1e10287..bf84b7945 100644
--- a/src/modules/systemlib/perf_counter.c
+++ b/src/modules/systemlib/perf_counter.c
@@ -321,6 +321,32 @@ perf_print_counter(perf_counter_t handle)
 	}
 }
 
+uint64_t
+perf_event_count(perf_counter_t handle)
+{
+	if (handle == NULL)
+		return 0;
+
+	switch (handle->type) {
+	case PC_COUNT:
+		return ((struct perf_ctr_count *)handle)->event_count;
+
+	case PC_ELAPSED: {
+		struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
+		return pce->event_count;
+	}
+
+	case PC_INTERVAL: {
+		struct perf_ctr_interval *pci = (struct perf_ctr_interval *)handle;
+		return pci->event_count;
+	}
+
+	default:
+		break;
+	}
+	return 0;
+}
+
 void
 perf_print_all(void)
 {
diff --git a/src/modules/systemlib/perf_counter.h b/src/modules/systemlib/perf_counter.h
index 4cd8b67a1..e1e3cbe95 100644
--- a/src/modules/systemlib/perf_counter.h
+++ b/src/modules/systemlib/perf_counter.h
@@ -135,6 +135,14 @@ __EXPORT extern void		perf_print_all(void);
  */
 __EXPORT extern void		perf_reset_all(void);
 
+/**
+ * Return current event_count
+ *
+ * @param handle		The counter returned from perf_alloc.
+ * @return			event_count
+ */
+__EXPORT extern uint64_t	perf_event_count(perf_counter_t handle);
+
 __END_DECLS
 
 #endif
diff --git a/src/modules/systemlib/pid/pid.c b/src/modules/systemlib/pid/pid.c
index 4996a8f66..77c952f52 100644
--- a/src/modules/systemlib/pid/pid.c
+++ b/src/modules/systemlib/pid/pid.c
@@ -51,6 +51,8 @@
 #include "pid.h"
 #include <math.h>
 
+#define SIGMA 0.000001f
+
 __EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax,
 		       float limit, uint8_t mode, float dt_min)
 {
@@ -165,20 +167,26 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo
 		d = 0.0f;
 	}
 
-	// Calculate the error integral and check for saturation
-	i = pid->integral + (error * dt);
+	if (pid->ki > 0.0f) {
+		// Calculate the error integral and check for saturation
+		i = pid->integral + (error * dt);
 
-	if (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit ||
-	    fabsf(i) > pid->intmax) {
-		i = pid->integral;		// If saturated then do not update integral value
-		pid->saturated = 1;
+		if ((pid->limit > SIGMA && (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit)) ||
+		    fabsf(i) > pid->intmax) {
+			i = pid->integral;		// If saturated then do not update integral value
+			pid->saturated = 1;
 
-	} else {
-		if (!isfinite(i)) {
-			i = 0.0f;
+		} else {
+			if (!isfinite(i)) {
+				i = 0.0f;
+			}
+
+			pid->integral = i;
+			pid->saturated = 0;
 		}
 
-		pid->integral = i;
+	} else {
+		i = 0.0f;
 		pid->saturated = 0;
 	}
 
@@ -186,11 +194,13 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo
 	float output = (error * pid->kp) + (i * pid->ki) + (d * pid->kd);
 
 	if (isfinite(output)) {
-		if (output > pid->limit) {
-			output = pid->limit;
+		if (pid->limit > SIGMA) {
+			if (output > pid->limit) {
+				output = pid->limit;
 
-		} else if (output < -pid->limit) {
-			output = -pid->limit;
+			} else if (output < -pid->limit) {
+				output = -pid->limit;
+			}
 		}
 
 		pid->last_output = output;
diff --git a/src/modules/systemlib/pwm_limit/pwm_limit.c b/src/modules/systemlib/pwm_limit/pwm_limit.c
new file mode 100644
index 000000000..cac3dc82a
--- /dev/null
+++ b/src/modules/systemlib/pwm_limit/pwm_limit.c
@@ -0,0 +1,133 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Julian Oes <joes@student.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 pwm_limit.c
+ *
+ * Lib to limit PWM output
+ *
+ * @author Julian Oes <joes@student.ethz.ch>
+ */
+
+#include "pwm_limit.h"
+#include <math.h>
+#include <stdbool.h>
+#include <drivers/drv_hrt.h>
+
+void pwm_limit_init(pwm_limit_t *limit)
+{
+	limit->state = LIMIT_STATE_OFF;
+	limit->time_armed = 0;
+	return;
+}
+
+void pwm_limit_calc(const bool armed, const unsigned num_channels, const uint16_t *disarmed_pwm, const uint16_t *min_pwm, const uint16_t *max_pwm, float *output, uint16_t *effective_pwm, pwm_limit_t *limit)
+{
+	/* first evaluate state changes */
+	switch (limit->state) {
+		case LIMIT_STATE_OFF:
+			if (armed)
+				limit->state = LIMIT_STATE_RAMP;
+			limit->time_armed = hrt_absolute_time();
+			break;
+		case LIMIT_STATE_INIT:
+			if (!armed)
+				limit->state = LIMIT_STATE_OFF;
+			else if (hrt_absolute_time() - limit->time_armed >= INIT_TIME_US)
+				limit->state = LIMIT_STATE_RAMP;
+			break;
+		case LIMIT_STATE_RAMP:
+			if (!armed)
+				limit->state = LIMIT_STATE_OFF;
+			else if (hrt_absolute_time() - limit->time_armed >= INIT_TIME_US + RAMP_TIME_US)
+				limit->state = LIMIT_STATE_ON;
+			break;
+		case LIMIT_STATE_ON:
+			if (!armed)
+				limit->state = LIMIT_STATE_OFF;
+			break;
+		default:
+			break;
+	}
+
+	unsigned progress;
+	uint16_t temp_pwm;
+
+	/* then set effective_pwm based on state */
+	switch (limit->state) {
+		case LIMIT_STATE_OFF:
+		case LIMIT_STATE_INIT:
+			for (unsigned i=0; i<num_channels; i++) {
+				effective_pwm[i] = disarmed_pwm[i];
+				output[i] = 0.0f;
+			}
+			break;
+		case LIMIT_STATE_RAMP:
+
+			progress = (hrt_absolute_time() - INIT_TIME_US - limit->time_armed)*10000 / RAMP_TIME_US;
+			for (unsigned i=0; i<num_channels; i++) {
+                
+				uint16_t ramp_min_pwm;
+                
+				/* if a disarmed pwm value was set, blend between disarmed and min */
+				if (disarmed_pwm[i] > 0) {
+
+					/* safeguard against overflows */
+					uint16_t disarmed = disarmed_pwm[i];
+					if (disarmed > min_pwm[i])
+						disarmed = min_pwm[i];
+
+					uint16_t disarmed_min_diff = min_pwm[i] - disarmed;
+					ramp_min_pwm = disarmed + (disarmed_min_diff * progress) / 10000;
+				} else {
+                    
+					/* no disarmed pwm value set, choose min pwm */
+					ramp_min_pwm = min_pwm[i];
+				}
+
+				effective_pwm[i] = output[i] * (max_pwm[i] - ramp_min_pwm)/2 + (max_pwm[i] + ramp_min_pwm)/2;
+				output[i] = (float)progress/10000.0f * output[i];
+			}
+			break;
+		case LIMIT_STATE_ON:
+			for (unsigned i=0; i<num_channels; i++) {
+				effective_pwm[i] = output[i] * (max_pwm[i] - min_pwm[i])/2 + (max_pwm[i] + min_pwm[i])/2;
+				/* effective_output stays the same */
+			}
+			break;
+		default:
+			break;
+	}
+	return;
+}
diff --git a/src/modules/systemlib/pwm_limit/pwm_limit.h b/src/modules/systemlib/pwm_limit/pwm_limit.h
new file mode 100644
index 000000000..9974770be
--- /dev/null
+++ b/src/modules/systemlib/pwm_limit/pwm_limit.h
@@ -0,0 +1,77 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Julian Oes <joes@student.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 pwm_limit.h
+ *
+ * Lib to limit PWM output
+ *
+ * @author Julian Oes <joes@student.ethz.ch>
+ */
+
+#ifndef PWM_LIMIT_H_
+#define PWM_LIMIT_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/*
+ * time for the ESCs to initialize
+ * (this is not actually needed if PWM is sent right after boot)
+ */
+#define INIT_TIME_US 500000
+/*
+ * time to slowly ramp up the ESCs
+ */
+#define RAMP_TIME_US 2500000
+
+typedef struct {
+	enum {
+		LIMIT_STATE_OFF = 0,
+		LIMIT_STATE_INIT,
+		LIMIT_STATE_RAMP,
+		LIMIT_STATE_ON
+	} state;
+	uint64_t time_armed;
+} pwm_limit_t;
+
+__BEGIN_DECLS
+
+__EXPORT void pwm_limit_init(pwm_limit_t *limit);
+
+__EXPORT void pwm_limit_calc(const bool armed, const unsigned num_channels, const uint16_t *disarmed_pwm, const uint16_t *min_pwm, const uint16_t *max_pwm, float *output, uint16_t *effective_pwm, pwm_limit_t *limit);
+
+__END_DECLS
+
+#endif /* PWM_LIMIT_H_ */
diff --git a/src/modules/systemlib/rc_check.c b/src/modules/systemlib/rc_check.c
new file mode 100644
index 000000000..b4350cc24
--- /dev/null
+++ b/src/modules/systemlib/rc_check.c
@@ -0,0 +1,151 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. 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 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 rc_check.c
+ *
+ * RC calibration check
+ */
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <fcntl.h>
+
+#include <systemlib/rc_check.h>
+#include <systemlib/param/param.h>
+#include <mavlink/mavlink_log.h>
+#include <uORB/topics/rc_channels.h>
+
+int rc_calibration_check(int mavlink_fd) {
+
+	char nbuf[20];
+	param_t _parameter_handles_min, _parameter_handles_trim, _parameter_handles_max,
+	_parameter_handles_rev, _parameter_handles_dz;
+
+	float param_min, param_max, param_trim, param_rev, param_dz;
+
+	/* first check channel mappings */
+			/* check which map param applies */
+		// if (map_by_channel[i] >= MAX_CONTROL_CHANNELS) {
+		// 	mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MAP >= # CHANS", i+1);
+		// 	/* give system time to flush error message in case there are more */
+		// 	usleep(100000);
+		// 	count++;
+		// }
+
+	int channel_fail_count = 0;
+
+	for (int i = 0; i < RC_CHANNELS_MAX; i++) {
+		/* should the channel be enabled? */
+		uint8_t count = 0;
+
+		/* min values */
+		sprintf(nbuf, "RC%d_MIN", i + 1);
+		_parameter_handles_min = param_find(nbuf);
+		param_get(_parameter_handles_min, &param_min);
+
+		/* trim values */
+		sprintf(nbuf, "RC%d_TRIM", i + 1);
+		_parameter_handles_trim = param_find(nbuf);
+		param_get(_parameter_handles_trim, &param_trim);
+
+		/* max values */
+		sprintf(nbuf, "RC%d_MAX", i + 1);
+		_parameter_handles_max = param_find(nbuf);
+		param_get(_parameter_handles_max, &param_max);
+
+		/* channel reverse */
+		sprintf(nbuf, "RC%d_REV", i + 1);
+		_parameter_handles_rev = param_find(nbuf);
+		param_get(_parameter_handles_rev, &param_rev);
+
+		/* channel deadzone */
+		sprintf(nbuf, "RC%d_DZ", i + 1);
+		_parameter_handles_dz = param_find(nbuf);
+		param_get(_parameter_handles_dz, &param_dz);
+
+		/* assert min..center..max ordering */
+		if (param_min < 500) {
+			count++;
+			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MIN < 500", i+1);
+			/* give system time to flush error message in case there are more */
+			usleep(100000);
+		}
+		if (param_max > 2500) {
+			count++;
+			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MAX > 2500", i+1);
+			/* give system time to flush error message in case there are more */
+			usleep(100000);
+		}
+		if (param_trim < param_min) {
+			count++;
+			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_TRIM < MIN (%d/%d)", i+1, (int)param_trim, (int)param_min);
+			/* give system time to flush error message in case there are more */
+			usleep(100000);
+		}
+		if (param_trim > param_max) {
+			count++;
+			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_TRIM > MAX (%d/%d)", i+1, (int)param_trim, (int)param_max);
+			/* give system time to flush error message in case there are more */
+			usleep(100000);
+		}
+
+		/* assert deadzone is sane */
+		if (param_dz > 500) {
+			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_DZ > 500", i+1);
+			/* give system time to flush error message in case there are more */
+			usleep(100000);
+			count++;
+		}
+
+		/* check which map param applies */
+		// if (map_by_channel[i] >= MAX_CONTROL_CHANNELS) {
+		// 	mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MAP >= # CHANS", i+1);
+		// 	/* give system time to flush error message in case there are more */
+		// 	usleep(100000);
+		// 	count++;
+		// }
+
+		/* sanity checks pass, enable channel */
+		if (count) {
+			mavlink_log_critical(mavlink_fd, "ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
+			warnx(mavlink_fd, "ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
+			usleep(100000);
+		}
+
+		channel_fail_count += count;
+	}
+
+	return channel_fail_count;
+}
diff --git a/src/modules/systemlib/rc_check.h b/src/modules/systemlib/rc_check.h
new file mode 100644
index 000000000..e70b83cce
--- /dev/null
+++ b/src/modules/systemlib/rc_check.h
@@ -0,0 +1,52 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. 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 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 rc_check.h
+ *
+ * RC calibration check
+ */
+
+#pragma once
+
+ __BEGIN_DECLS
+
+/**
+ * Check the RC calibration
+ *
+ * @return			0 / OK if RC calibration is ok, index + 1 of the first
+ *				channel that failed else (so 1 == first channel failed)
+ */
+__EXPORT int	rc_calibration_check(int mavlink_fd);
+
+__END_DECLS
diff --git a/src/modules/systemlib/systemlib.c b/src/modules/systemlib/systemlib.c
index 3283aad8a..57a751e1c 100644
--- a/src/modules/systemlib/systemlib.c
+++ b/src/modules/systemlib/systemlib.c
@@ -43,13 +43,29 @@
 #include <fcntl.h>
 #include <sched.h>
 #include <signal.h>
-#include <sys/stat.h>
 #include <unistd.h>
 #include <float.h>
 #include <string.h>
 
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <stm32_pwr.h>
+
 #include "systemlib.h"
 
+void
+systemreset(bool to_bootloader)
+{
+	if (to_bootloader) {
+		stm32_pwr_enablebkp();
+
+		/* XXX wow, this is evil - write a magic number into backup register zero */
+		*(uint32_t *)0x40002850 = 0xb007b007;
+	}
+	up_systemreset();
+}
+
 static void kill_task(FAR struct tcb_s *tcb, FAR void *arg);
 
 void killall()
diff --git a/src/modules/systemlib/systemlib.h b/src/modules/systemlib/systemlib.h
index 0194b5e52..3728f2067 100644
--- a/src/modules/systemlib/systemlib.h
+++ b/src/modules/systemlib/systemlib.h
@@ -42,11 +42,11 @@
 #include <float.h>
 #include <stdint.h>
 
-/** Reboots the board */
-extern void up_systemreset(void) noreturn_function;
-
 __BEGIN_DECLS
 
+/** Reboots the board */
+__EXPORT void systemreset(bool to_bootloader) noreturn_function;
+
 /** Sends SIGUSR1 to all processes */
 __EXPORT void killall(void);