Merge remote-tracking branch 'upstream/master' into fwlandingterrain

22 files changed, 1640 insertions, 349 deletions

diff --git a/src/modules/fw_att_control/fw_att_control_main.cpp b/src/modules/fw_att_control/fw_att_control_main.cpp
index ad873203e..c60d8d348 100644
--- a/src/modules/fw_att_control/fw_att_control_main.cpp
+++ b/src/modules/fw_att_control/fw_att_control_main.cpp
@@ -63,6 +63,7 @@
 #include <uORB/topics/vehicle_control_mode.h>
 #include <uORB/topics/parameter_update.h>
 #include <uORB/topics/vehicle_global_position.h>
+#include <uORB/topics/vehicle_status.h>
 #include <systemlib/param/param.h>
 #include <systemlib/err.h>
 #include <systemlib/pid/pid.h>
@@ -124,6 +125,7 @@ private:
 	int 		_params_sub;			/**< notification of parameter updates */
 	int 		_manual_sub;			/**< notification of manual control updates */
 	int		_global_pos_sub;		/**< global position subscription */
+	int		_vehicle_status_sub;		/**< vehicle status subscription */
 
 	orb_advert_t	_rate_sp_pub;			/**< rate setpoint publication */
 	orb_advert_t	_attitude_sp_pub;		/**< attitude setpoint point */
@@ -139,6 +141,7 @@ private:
 	struct actuator_controls_s			_actuators;		/**< actuator control inputs */
 	struct actuator_controls_s			_actuators_airframe;	/**< actuator control inputs */
 	struct vehicle_global_position_s		_global_pos;		/**< global position */
+	struct vehicle_status_s				_vehicle_status;	/**< vehicle status */
 
 	perf_counter_t	_loop_perf;			/**< loop performance counter */
 	perf_counter_t	_nonfinite_input_perf;		/**< performance counter for non finite input */
@@ -276,6 +279,11 @@ private:
 	void		global_pos_poll();
 
 	/**
+	 * Check for vehicle status updates.
+	 */
+	void		vehicle_status_poll();
+
+	/**
 	 * Shim for calling task_main from task_create.
 	 */
 	static void	task_main_trampoline(int argc, char *argv[]);
@@ -313,6 +321,7 @@ FixedwingAttitudeControl::FixedwingAttitudeControl() :
 	_params_sub(-1),
 	_manual_sub(-1),
 	_global_pos_sub(-1),
+	_vehicle_status_sub(-1),
 
 /* publications */
 	_rate_sp_pub(-1),
@@ -338,6 +347,7 @@ FixedwingAttitudeControl::FixedwingAttitudeControl() :
 	_actuators = {};
 	_actuators_airframe = {};
 	_global_pos = {};
+	_vehicle_status = {};
 
 
 	_parameter_handles.tconst = param_find("FW_ATT_TC");
@@ -561,6 +571,18 @@ FixedwingAttitudeControl::global_pos_poll()
 }
 
 void
+FixedwingAttitudeControl::vehicle_status_poll()
+{
+	/* check if there is new status information */
+	bool vehicle_status_updated;
+	orb_check(_vehicle_status_sub, &vehicle_status_updated);
+
+	if (vehicle_status_updated) {
+		orb_copy(ORB_ID(vehicle_status), _vehicle_status_sub, &_vehicle_status);
+	}
+}
+
+void
 FixedwingAttitudeControl::task_main_trampoline(int argc, char *argv[])
 {
 	att_control::g_control->task_main();
@@ -585,6 +607,7 @@ FixedwingAttitudeControl::task_main()
 	_params_sub = orb_subscribe(ORB_ID(parameter_update));
 	_manual_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
 	_global_pos_sub = orb_subscribe(ORB_ID(vehicle_global_position));
+	_vehicle_status_sub = orb_subscribe(ORB_ID(vehicle_status));
 
 	/* rate limit vehicle status updates to 5Hz */
 	orb_set_interval(_vcontrol_mode_sub, 200);
@@ -599,6 +622,7 @@ FixedwingAttitudeControl::task_main()
 	vehicle_accel_poll();
 	vehicle_control_mode_poll();
 	vehicle_manual_poll();
+	vehicle_status_poll();
 
 	/* wakeup source(s) */
 	struct pollfd fds[2];
@@ -667,6 +691,8 @@ FixedwingAttitudeControl::task_main()
 
 			global_pos_poll();
 
+			vehicle_status_poll();
+
 			/* lock integrator until control is started */
 			bool lock_integrator;
 
@@ -779,6 +805,13 @@ FixedwingAttitudeControl::task_main()
 					}
 				}
 
+				/* If the aircraft is on ground reset the integrators */
+				if (_vehicle_status.condition_landed) {
+					_roll_ctrl.reset_integrator();
+					_pitch_ctrl.reset_integrator();
+					_yaw_ctrl.reset_integrator();
+				}
+
 				/* Prepare speed_body_u and speed_body_w */
 				float speed_body_u = 0.0f;
 				float speed_body_v = 0.0f;
diff --git a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
index 77eb78097..eb4ffdabb 100644
--- a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
+++ b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
@@ -208,6 +208,7 @@ private:
 		float max_climb_rate;
 		float climbout_diff;
 		float heightrate_p;
+		float heightrate_ff;
 		float speedrate_p;
 		float throttle_damp;
 		float integrator_gain;
@@ -254,6 +255,7 @@ private:
 		param_t max_climb_rate;
 		param_t climbout_diff;
 		param_t heightrate_p;
+		param_t heightrate_ff;
 		param_t speedrate_p;
 		param_t throttle_damp;
 		param_t integrator_gain;
@@ -374,7 +376,8 @@ private:
 			bool climbout_mode, float climbout_pitch_min_rad,
 			float altitude,
 			const math::Vector<3> &ground_speed,
-			tecs_mode mode = TECS_MODE_NORMAL);
+			tecs_mode mode = TECS_MODE_NORMAL,
+			bool pitch_max_special = false);
 
 };
 
@@ -487,6 +490,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.speed_weight = 			param_find("FW_T_SPDWEIGHT");
 	_parameter_handles.pitch_damping = 			param_find("FW_T_PTCH_DAMP");
 	_parameter_handles.heightrate_p =			param_find("FW_T_HRATE_P");
+	_parameter_handles.heightrate_ff =			param_find("FW_T_HRATE_FF");
 	_parameter_handles.speedrate_p =			param_find("FW_T_SRATE_P");
 
 	/* fetch initial parameter values */
@@ -556,6 +560,7 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.climbout_diff, &(_parameters.climbout_diff));
 
 	param_get(_parameter_handles.heightrate_p, &(_parameters.heightrate_p));
+	param_get(_parameter_handles.heightrate_ff, &(_parameters.heightrate_ff));
 	param_get(_parameter_handles.speedrate_p, &(_parameters.speedrate_p));
 
 	param_get(_parameter_handles.land_slope_angle, &(_parameters.land_slope_angle));
@@ -593,6 +598,7 @@ FixedwingPositionControl::parameters_update()
 	_tecs.set_indicated_airspeed_max(_parameters.airspeed_max);
 	_tecs.set_max_climb_rate(_parameters.max_climb_rate);
 	_tecs.set_heightrate_p(_parameters.heightrate_p);
+	_tecs.set_heightrate_ff(_parameters.heightrate_ff);
 	_tecs.set_speedrate_p(_parameters.speedrate_p);
 
 	/* sanity check parameters */
@@ -1103,7 +1109,13 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 					LAUNCHDETECTION_RES_DETECTED_ENABLEMOTORS ?
 					launchDetector.getThrottlePreTakeoff() : _parameters.throttle_max;
 
-				/* apply minimum pitch and limit roll if target altitude is not within 10 meters */
+				/* select maximum pitch: the launchdetector may impose another limit for the pitch
+				 * depending on the state of the launch */
+				float takeoff_pitch_max_deg = launchDetector.getPitchMax(_parameters.pitch_limit_max);
+				float takeoff_pitch_max_rad = math::radians(takeoff_pitch_max_deg);
+
+				/* apply minimum pitch and limit roll if target altitude is not within climbout_diff
+				 * meters */
 				if (_parameters.climbout_diff > 0.001f && altitude_error > _parameters.climbout_diff) {
 
 					/* enforce a minimum of 10 degrees pitch up on takeoff, or take parameter */
@@ -1111,7 +1123,7 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 							calculate_target_airspeed(1.3f * _parameters.airspeed_min),
 							eas2tas,
 							math::radians(_parameters.pitch_limit_min),
-							math::radians(_parameters.pitch_limit_max),
+							takeoff_pitch_max_rad,
 							_parameters.throttle_min, takeoff_throttle,
 							_parameters.throttle_cruise,
 							true,
@@ -1119,7 +1131,8 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 							math::radians(10.0f)),
 							_global_pos.alt,
 							ground_speed,
-							TECS_MODE_TAKEOFF);
+							TECS_MODE_TAKEOFF,
+							takeoff_pitch_max_deg != _parameters.pitch_limit_max);
 
 					/* limit roll motion to ensure enough lift */
 					_att_sp.roll_body = math::constrain(_att_sp.roll_body, math::radians(-15.0f),
@@ -1187,7 +1200,7 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 
 	/* Copy thrust and pitch values from tecs
 	 * making sure again that the correct thrust is used,
-	 * without depending on library calls */
+	 * without depending on library calls for safety reasons */
 	if (pos_sp_triplet.current.type == SETPOINT_TYPE_TAKEOFF &&
 			launch_detection_state != LAUNCHDETECTION_RES_DETECTED_ENABLEMOTORS) {
 		_att_sp.thrust = launchDetector.getThrottlePreTakeoff();
@@ -1372,7 +1385,7 @@ void FixedwingPositionControl::tecs_update_pitch_throttle(float alt_sp, float v_
 		bool climbout_mode, float climbout_pitch_min_rad,
 		float altitude,
 		const math::Vector<3> &ground_speed,
-		tecs_mode mode)
+		tecs_mode mode, bool pitch_max_special)
 {
 	if (_mTecs.getEnabled()) {
 		/* Using mtecs library: prepare arguments for mtecs call */
@@ -1387,6 +1400,14 @@ void FixedwingPositionControl::tecs_update_pitch_throttle(float alt_sp, float v_
 		} else {
 			limitOverride.disablePitchMinOverride();
 		}
+
+		if (pitch_max_special) {
+			/* Use the maximum pitch from the argument */
+			limitOverride.enablePitchMaxOverride(M_RAD_TO_DEG_F * pitch_max_rad);
+		} else {
+			/* use pitch max set by MT param */
+			limitOverride.disablePitchMaxOverride();
+		}
 		_mTecs.updateAltitudeSpeed(flightPathAngle, altitude, alt_sp, _airspeed.true_airspeed_m_s, v_sp, mode,
 				limitOverride);
 	} else {
diff --git a/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c b/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
index 859cef8bd..41a366538 100644
--- a/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
+++ b/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
@@ -358,6 +358,13 @@ PARAM_DEFINE_FLOAT(FW_T_PTCH_DAMP, 0.0f);
 PARAM_DEFINE_FLOAT(FW_T_HRATE_P, 0.05f);
 
 /**
+ * Height rate FF factor
+ *
+ * @group Fixed Wing TECS
+ */
+PARAM_DEFINE_FLOAT(FW_T_HRATE_FF, 0.0f);
+
+/**
  * Speed rate P factor
  *
  * @group Fixed Wing TECS
diff --git a/src/modules/mavlink/mavlink_ftp.cpp b/src/modules/mavlink/mavlink_ftp.cpp
index 5b65dc369..2a85c3702 100644
--- a/src/modules/mavlink/mavlink_ftp.cpp
+++ b/src/modules/mavlink/mavlink_ftp.cpp
@@ -31,38 +31,38 @@
  *
  ****************************************************************************/
 
-#include <crc32.h>
+/// @file mavlink_ftp.cpp
+///	@author px4dev, Don Gagne <don@thegagnes.com>
+
 #include <unistd.h>
 #include <stdio.h>
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <errno.h>
 
 #include "mavlink_ftp.h"
+#include "mavlink_tests/mavlink_ftp_test.h"
 
 // Uncomment the line below to get better debug output. Never commit with this left on.
 //#define MAVLINK_FTP_DEBUG
 
-MavlinkFTP *MavlinkFTP::_server;
-
 MavlinkFTP *
-MavlinkFTP::getServer()
+MavlinkFTP::get_server(void)
 {
-	// XXX this really cries out for some locking...
-	if (_server == nullptr) {
-		_server = new MavlinkFTP;
-	}
-	return _server;
+	static MavlinkFTP server;
+        return &server;
 }
 
 MavlinkFTP::MavlinkFTP() :
-	_session_fds{},
-	_workBufs{},
-	_workFree{},
-	_lock{}
+	_request_bufs{},
+	_request_queue{},
+	_request_queue_sem{},
+	_utRcvMsgFunc{},
+	_ftp_test{}
 {
 	// initialise the request freelist
-	dq_init(&_workFree);
-	sem_init(&_lock, 0, 1);
+	dq_init(&_request_queue);
+	sem_init(&_request_queue_sem, 0, 1);
 
 	// initialize session list
 	for (size_t i=0; i<kMaxSession; i++) {
@@ -71,167 +71,240 @@ MavlinkFTP::MavlinkFTP() :
 
 	// drop work entries onto the free list
 	for (unsigned i = 0; i < kRequestQueueSize; i++) {
-		_qFree(&_workBufs[i]);
+		_return_request(&_request_bufs[i]);
 	}
 
 }
 
+#ifdef MAVLINK_FTP_UNIT_TEST
+void
+MavlinkFTP::set_unittest_worker(ReceiveMessageFunc_t rcvMsgFunc, MavlinkFtpTest *ftp_test)
+{
+	_utRcvMsgFunc = rcvMsgFunc;
+	_ftp_test = ftp_test;
+}
+#endif
+
 void
 MavlinkFTP::handle_message(Mavlink* mavlink, mavlink_message_t *msg)
 {
 	// get a free request
-	auto req = _dqFree();
+	struct Request* req = _get_request();
 
 	// if we couldn't get a request slot, just drop it
-	if (req != nullptr) {
-
-		// decode the request
-		if (req->decode(mavlink, msg)) {
+	if (req == nullptr) {
+		warnx("Dropping FTP request: queue full\n");
+		return;
+	}
 
-			// and queue it for the worker
-			work_queue(LPWORK, &req->work, &MavlinkFTP::_workerTrampoline, req, 0);
-		} else {
-			_qFree(req);
+	if (msg->msgid == MAVLINK_MSG_ID_FILE_TRANSFER_PROTOCOL) {
+		mavlink_msg_file_transfer_protocol_decode(msg, &req->message);
+		
+#ifdef MAVLINK_FTP_UNIT_TEST
+		if (!_utRcvMsgFunc) {
+			warnx("Incorrectly written unit test\n");
+			return;
+		}
+		// We use fake ids when unit testing
+		req->serverSystemId = MavlinkFtpTest::serverSystemId;
+		req->serverComponentId = MavlinkFtpTest::serverComponentId;
+		req->serverChannel = MavlinkFtpTest::serverChannel;
+#else
+		// Not unit testing, use the real thing
+		req->serverSystemId = mavlink->get_system_id();
+		req->serverComponentId = mavlink->get_component_id();
+		req->serverChannel = mavlink->get_channel();
+#endif
+		
+		// This is the system id we want to target when sending
+		req->targetSystemId = msg->sysid;
+			
+		if (req->message.target_system == req->serverSystemId) {
+			req->mavlink = mavlink;
+#ifdef MAVLINK_FTP_UNIT_TEST
+			// We are running in Unit Test mode. Don't queue, just call _worket directly.
+			_process_request(req);
+#else
+			// We are running in normal mode. Queue the request to the worker
+			work_queue(LPWORK, &req->work, &MavlinkFTP::_worker_trampoline, req, 0);
+#endif
+            return;
 		}
 	}
+
+	_return_request(req);
 }
 
+/// @brief Queued static work queue routine to handle mavlink messages
 void
-MavlinkFTP::_workerTrampoline(void *arg)
+MavlinkFTP::_worker_trampoline(void *arg)
 {
-	auto req = reinterpret_cast<Request *>(arg);
-	auto server = MavlinkFTP::getServer();
+	Request* req = reinterpret_cast<Request *>(arg);
+	MavlinkFTP* server = MavlinkFTP::get_server();
 
 	// call the server worker with the work item
-	server->_worker(req);
+	server->_process_request(req);
 }
 
+/// @brief Processes an FTP message
 void
-MavlinkFTP::_worker(Request *req)
+MavlinkFTP::_process_request(Request *req)
 {
-	auto hdr = req->header();
+	PayloadHeader *payload = reinterpret_cast<PayloadHeader *>(&req->message.payload[0]);
+
 	ErrorCode errorCode = kErrNone;
-	uint32_t messageCRC;
 
 	// basic sanity checks; must validate length before use
-	if (hdr->size > kMaxDataLength) {
-		errorCode = kErrNoRequest;
+	if (payload->size > kMaxDataLength) {
+		errorCode = kErrInvalidDataSize;
 		goto out;
 	}
 
-	// check request CRC to make sure this is one of ours
-	messageCRC = hdr->crc32;
-	hdr->crc32 = 0;
-	hdr->padding[0] = 0;
-	hdr->padding[1] = 0;
-	hdr->padding[2] = 0;
-	if (crc32(req->rawData(), req->dataSize()) != messageCRC) {
-		errorCode = kErrNoRequest;
-		goto out;
-		warnx("ftp: bad crc");
-	}
-
 #ifdef MAVLINK_FTP_DEBUG
-	printf("ftp: channel %u opc %u size %u offset %u\n", req->channel(), hdr->opcode, hdr->size, hdr->offset);
+	printf("ftp: channel %u opc %u size %u offset %u\n", req->serverChannel, payload->opcode, payload->size, payload->offset);
 #endif
 
-	switch (hdr->opcode) {
+	switch (payload->opcode) {
 	case kCmdNone:
 		break;
 
-	case kCmdTerminate:
-		errorCode = _workTerminate(req);
+	case kCmdTerminateSession:
+		errorCode = _workTerminate(payload);
 		break;
 
-	case kCmdReset:
-		errorCode = _workReset();
+	case kCmdResetSessions:
+		errorCode = _workReset(payload);
 		break;
 
-	case kCmdList:
-		errorCode = _workList(req);
+	case kCmdListDirectory:
+		errorCode = _workList(payload);
 		break;
 
-	case kCmdOpen:
-		errorCode = _workOpen(req, false);
+	case kCmdOpenFile:
+		errorCode = _workOpen(payload, false);
 		break;
 
-	case kCmdCreate:
-		errorCode = _workOpen(req, true);
+	case kCmdCreateFile:
+		errorCode = _workOpen(payload, true);
 		break;
 
-	case kCmdRead:
-		errorCode = _workRead(req);
+	case kCmdReadFile:
+		errorCode = _workRead(payload);
 		break;
 
-	case kCmdWrite:
-		errorCode = _workWrite(req);
+	case kCmdWriteFile:
+		errorCode = _workWrite(payload);
 		break;
 
-	case kCmdRemove:
-		errorCode = _workRemove(req);
+	case kCmdRemoveFile:
+		errorCode = _workRemoveFile(payload);
 		break;
 
+	case kCmdCreateDirectory:
+		errorCode = _workCreateDirectory(payload);
+		break;
+			
+	case kCmdRemoveDirectory:
+		errorCode = _workRemoveDirectory(payload);
+		break;
+			
 	default:
-		errorCode = kErrNoRequest;
+		errorCode = kErrUnknownCommand;
 		break;	
 	}
 
 out:
 	// handle success vs. error
 	if (errorCode == kErrNone) {
-		hdr->opcode = kRspAck;
+		payload->req_opcode = payload->opcode;
+		payload->opcode = kRspAck;
 #ifdef MAVLINK_FTP_DEBUG
 		warnx("FTP: ack\n");
 #endif
 	} else {
 		warnx("FTP: nak %u", errorCode);
-		hdr->opcode = kRspNak;
-		hdr->size = 1;
-		hdr->data[0] = errorCode;
+		payload->req_opcode = payload->opcode;
+		payload->opcode = kRspNak;
+		payload->size = 1;
+		payload->data[0] = errorCode;
+		if (errorCode == kErrFailErrno) {
+			payload->size = 2;
+			payload->data[1] = errno;
+		}
 	}
 
+	
 	// respond to the request
 	_reply(req);
 
-	// free the request buffer back to the freelist
-	_qFree(req);
+	_return_request(req);
 }
 
+/// @brief Sends the specified FTP reponse message out through mavlink
 void
 MavlinkFTP::_reply(Request *req)
 {
-	auto hdr = req->header();
+	PayloadHeader *payload = reinterpret_cast<PayloadHeader *>(&req->message.payload[0]);
 	
-	hdr->seqNumber = req->header()->seqNumber + 1;
+	payload->seqNumber = payload->seqNumber + 1;
 
-	// message is assumed to be already constructed in the request buffer, so generate the CRC
-	hdr->crc32 = 0;
-	hdr->padding[0] = 0;
-	hdr->padding[1] = 0;
-	hdr->padding[2] = 0;
-	hdr->crc32 = crc32(req->rawData(), req->dataSize());
+	mavlink_message_t msg;
+	msg.checksum = 0;
+#ifndef MAVLINK_FTP_UNIT_TEST
+	uint16_t len =
+#endif
+	mavlink_msg_file_transfer_protocol_pack_chan(req->serverSystemId,	// Sender system id
+								    req->serverComponentId,	// Sender component id
+								    req->serverChannel,		// Channel to send on
+								    &msg,			// Message to pack payload into
+								    0,				// Target network
+								    req->targetSystemId,	// Target system id
+								    0,				// Target component id
+								    (const uint8_t*)payload);	// Payload to pack into message
+	
+	bool success = true;
+#ifdef MAVLINK_FTP_UNIT_TEST
+	// Unit test hook is set, call that instead
+	_utRcvMsgFunc(&msg, _ftp_test);
+#else
+	Mavlink	*mavlink = req->mavlink;
+	
+	mavlink->lockMessageBufferMutex();
+	success = mavlink->message_buffer_write(&msg, len);
+	mavlink->unlockMessageBufferMutex();
+		
+#endif
 
-	// then pack and send the reply back to the request source
-	req->reply();
+	if (!success) {
+		warnx("FTP TX ERR");
+	}
+#ifdef MAVLINK_FTP_DEBUG
+	else {
+		warnx("wrote: sys: %d, comp: %d, chan: %d, checksum: %d",
+		      req->serverSystemId,
+		      req->serverComponentId,
+		      req->serverChannel,
+		      msg.checksum);
+	}
+#endif
 }
 
+/// @brief Responds to a List command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workList(Request *req)
+MavlinkFTP::_workList(PayloadHeader* payload)
 {
-	auto hdr = req->header();
-    
     char dirPath[kMaxDataLength];
-    strncpy(dirPath, req->dataAsCString(), kMaxDataLength);
+    strncpy(dirPath, _data_as_cstring(payload), kMaxDataLength);
     
 	DIR *dp = opendir(dirPath);
 
 	if (dp == nullptr) {
 		warnx("FTP: can't open path '%s'", dirPath);
-		return kErrNotDir;
+		return kErrFailErrno;
 	}
     
 #ifdef MAVLINK_FTP_DEBUG
-	warnx("FTP: list %s offset %d", dirPath, hdr->offset);
+	warnx("FTP: list %s offset %d", dirPath, payload->offset);
 #endif
 
 	ErrorCode errorCode = kErrNone;
@@ -239,19 +312,19 @@ MavlinkFTP::_workList(Request *req)
 	unsigned offset = 0;
 
 	// move to the requested offset
-	seekdir(dp, hdr->offset);
+	seekdir(dp, payload->offset);
 
 	for (;;) {
 		// read the directory entry
 		if (readdir_r(dp, &entry, &result)) {
 			warnx("FTP: list %s readdir_r failure\n", dirPath);
-			errorCode = kErrIO;
+			errorCode = kErrFailErrno;
 			break;
 		}
 
 		// no more entries?
 		if (result == nullptr) {
-			if (hdr->offset != 0 && offset == 0) {
+			if (payload->offset != 0 && offset == 0) {
 				// User is requesting subsequent dir entries but there were none. This means the user asked
 				// to seek past EOF.
 				errorCode = kErrEOF;
@@ -276,14 +349,22 @@ MavlinkFTP::_workList(Request *req)
 			}
 			break;
 		case DTYPE_DIRECTORY:
-			direntType = kDirentDir;
+			if (strcmp(entry.d_name, ".") == 0 || strcmp(entry.d_name, "..") == 0) {
+				// Don't bother sending these back
+				direntType = kDirentSkip;
+			} else {
+				direntType = kDirentDir;
+			}
 			break;
 		default:
-			direntType = kDirentUnknown;
-			break;
+			// We only send back file and diretory entries, skip everything else
+			direntType = kDirentSkip;
 		}
 		
-		if (entry.d_type == DTYPE_FILE) {
+		if (direntType == kDirentSkip) {
+			// Skip send only dirent identifier
+			buf[0] = '\0';
+		} else if (direntType == kDirentFile) {
 			// Files send filename and file length
 			snprintf(buf, sizeof(buf), "%s\t%d", entry.d_name, fileSize);
 		} else {
@@ -299,94 +380,95 @@ MavlinkFTP::_workList(Request *req)
 		}
 		
 		// Move the data into the buffer
-		hdr->data[offset++] = direntType;
-		strcpy((char *)&hdr->data[offset], buf);
+		payload->data[offset++] = direntType;
+		strcpy((char *)&payload->data[offset], buf);
 #ifdef MAVLINK_FTP_DEBUG
-		printf("FTP: list %s %s\n", dirPath, (char *)&hdr->data[offset-1]);
+		printf("FTP: list %s %s\n", dirPath, (char *)&payload->data[offset-1]);
 #endif
 		offset += nameLen + 1;
 	}
 
 	closedir(dp);
-	hdr->size = offset;
+	payload->size = offset;
 
 	return errorCode;
 }
 
+/// @brief Responds to an Open command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workOpen(Request *req, bool create)
+MavlinkFTP::_workOpen(PayloadHeader* payload, bool create)
 {
-	auto hdr = req->header();
-    
-	int session_index = _findUnusedSession();
+	int session_index = _find_unused_session();
 	if (session_index < 0) {
-		return kErrNoSession;
+		warnx("FTP: Open failed - out of sessions\n");
+		return kErrNoSessionsAvailable;
 	}
-
+	
+	char *filename = _data_as_cstring(payload);
 	
 	uint32_t fileSize = 0;
 	if (!create) {
 		struct stat st;
-		if (stat(req->dataAsCString(), &st) != 0) {
-			return kErrNotFile;
+		if (stat(filename, &st) != 0) {
+			return kErrFailErrno;
 		}
 		fileSize = st.st_size;
 	}
 
 	int oflag = create ? (O_CREAT | O_EXCL | O_APPEND) : O_RDONLY;
     
-	int fd = ::open(req->dataAsCString(), oflag);
+	int fd = ::open(filename, oflag);
 	if (fd < 0) {
-		return create ? kErrPerm : kErrNotFile;
+		return kErrFailErrno;
 	}
 	_session_fds[session_index] = fd;
 
-	hdr->session = session_index;
+	payload->session = session_index;
 	if (create) {
-		hdr->size = 0;
+		payload->size = 0;
 	} else {
-		hdr->size = sizeof(uint32_t);
-		*((uint32_t*)hdr->data) = fileSize;
+		payload->size = sizeof(uint32_t);
+		*((uint32_t*)payload->data) = fileSize;
 	}
 
 	return kErrNone;
 }
 
+/// @brief Responds to a Read command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workRead(Request *req)
+MavlinkFTP::_workRead(PayloadHeader* payload)
 {
-	auto hdr = req->header();
-
-	int session_index = hdr->session;
+	int session_index = payload->session;
 
-	if (!_validSession(session_index)) {
-		return kErrNoSession;
+	if (!_valid_session(session_index)) {
+		return kErrInvalidSession;
 	}
 
 	// Seek to the specified position
 #ifdef MAVLINK_FTP_DEBUG
-	warnx("seek %d", hdr->offset);
+	warnx("seek %d", payload->offset);
 #endif
-	if (lseek(_session_fds[session_index], hdr->offset, SEEK_SET) < 0) {
+	if (lseek(_session_fds[session_index], payload->offset, SEEK_SET) < 0) {
 		// Unable to see to the specified location
 		warnx("seek fail");
 		return kErrEOF;
 	}
 
-	int bytes_read = ::read(_session_fds[session_index], &hdr->data[0], kMaxDataLength);
+	int bytes_read = ::read(_session_fds[session_index], &payload->data[0], kMaxDataLength);
 	if (bytes_read < 0) {
 		// Negative return indicates error other than eof
 		warnx("read fail %d", bytes_read);
-		return kErrIO;
+		return kErrFailErrno;
 	}
 
-	hdr->size = bytes_read;
+	payload->size = bytes_read;
 
 	return kErrNone;
 }
 
+/// @brief Responds to a Write command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workWrite(Request *req)
+MavlinkFTP::_workWrite(PayloadHeader* payload)
 {
 #if 0
     // NYI: Coming soon
@@ -409,35 +491,44 @@ MavlinkFTP::_workWrite(Request *req)
 	hdr->size = result;
 	return kErrNone;
 #else
-	return kErrPerm;
+	return kErrUnknownCommand;
 #endif
 }
 
+/// @brief Responds to a RemoveFile command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workRemove(Request *req)
+MavlinkFTP::_workRemoveFile(PayloadHeader* payload)
 {
-	//auto hdr = req->header();
-
-	// for now, send error reply
-	return kErrPerm;
+	char file[kMaxDataLength];
+	strncpy(file, _data_as_cstring(payload), kMaxDataLength);
+	
+	if (unlink(file) == 0) {
+		payload->size = 0;
+		return kErrNone;
+	} else {
+		return kErrFailErrno;
+	}
 }
 
+/// @brief Responds to a Terminate command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workTerminate(Request *req)
+MavlinkFTP::_workTerminate(PayloadHeader* payload)
 {
-	auto hdr = req->header();
-    
-	if (!_validSession(hdr->session)) {
-		return kErrNoSession;
+	if (!_valid_session(payload->session)) {
+		return kErrInvalidSession;
 	}
     
-	::close(_session_fds[hdr->session]);
+	::close(_session_fds[payload->session]);
+	_session_fds[payload->session] = -1;
+	
+	payload->size = 0;
 
 	return kErrNone;
 }
 
+/// @brief Responds to a Reset command
 MavlinkFTP::ErrorCode
-MavlinkFTP::_workReset(void)
+MavlinkFTP::_workReset(PayloadHeader* payload)
 {
 	for (size_t i=0; i<kMaxSession; i++) {
 		if (_session_fds[i] != -1) {
@@ -446,11 +537,44 @@ MavlinkFTP::_workReset(void)
 		}
 	}
 
+	payload->size = 0;
+	
 	return kErrNone;
 }
 
+/// @brief Responds to a RemoveDirectory command
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workRemoveDirectory(PayloadHeader* payload)
+{
+	char dir[kMaxDataLength];
+	strncpy(dir, _data_as_cstring(payload), kMaxDataLength);
+	
+	if (rmdir(dir) == 0) {
+		payload->size = 0;
+		return kErrNone;
+	} else {
+		return kErrFailErrno;
+	}
+}
+
+/// @brief Responds to a CreateDirectory command
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workCreateDirectory(PayloadHeader* payload)
+{
+	char dir[kMaxDataLength];
+	strncpy(dir, _data_as_cstring(payload), kMaxDataLength);
+	
+	if (mkdir(dir, S_IRWXU | S_IRWXG | S_IRWXO) == 0) {
+		payload->size = 0;
+		return kErrNone;
+	} else {
+		return kErrFailErrno;
+	}
+}
+
+/// @brief Returns true if the specified session is a valid open session
 bool
-MavlinkFTP::_validSession(unsigned index)
+MavlinkFTP::_valid_session(unsigned index)
 {
 	if ((index >= kMaxSession) || (_session_fds[index] < 0)) {
 		return false;
@@ -458,8 +582,9 @@ MavlinkFTP::_validSession(unsigned index)
 	return true;
 }
 
+/// @brief Returns an unused session index
 int
-MavlinkFTP::_findUnusedSession(void)
+MavlinkFTP::_find_unused_session(void)
 {
 	for (size_t i=0; i<kMaxSession; i++) {
 		if (_session_fds[i] == -1) {
@@ -470,16 +595,53 @@ MavlinkFTP::_findUnusedSession(void)
 	return -1;
 }
 
+/// @brief Guarantees that the payload data is null terminated.
+///     @return Returns a pointer to the payload data as a char *
 char *
-MavlinkFTP::Request::dataAsCString()
+MavlinkFTP::_data_as_cstring(PayloadHeader* payload)
 {
 	// guarantee nul termination
-	if (header()->size < kMaxDataLength) {
-		requestData()[header()->size] = '\0';
+	if (payload->size < kMaxDataLength) {
+		payload->data[payload->size] = '\0';
 	} else {
-		requestData()[kMaxDataLength - 1] = '\0';
+		payload->data[kMaxDataLength - 1] = '\0';
 	}
 
 	// and return data
-	return (char *)&(header()->data[0]);
+	return (char *)&(payload->data[0]);
+}
+
+/// @brief Returns a unused Request entry. NULL if none available.
+MavlinkFTP::Request *
+MavlinkFTP::_get_request(void)
+{
+	_lock_request_queue();
+	Request* req = reinterpret_cast<Request *>(dq_remfirst(&_request_queue));
+	_unlock_request_queue();
+	return req;
+}
+
+/// @brief Locks a semaphore to provide exclusive access to the request queue
+void
+MavlinkFTP::_lock_request_queue(void)
+{
+	do {}
+	while (sem_wait(&_request_queue_sem) != 0);
+}
+
+/// @brief Unlocks the semaphore providing exclusive access to the request queue
+void
+MavlinkFTP::_unlock_request_queue(void)
+{
+	sem_post(&_request_queue_sem);
 }
+
+/// @brief Returns a no longer needed request to the queue
+void
+MavlinkFTP::_return_request(Request *req)
+{
+	_lock_request_queue();
+	dq_addlast(&req->work.dq, &_request_queue);
+	_unlock_request_queue();
+}
+
diff --git a/src/modules/mavlink/mavlink_ftp.h b/src/modules/mavlink/mavlink_ftp.h
index 1dd8f102e..657e2f855 100644
--- a/src/modules/mavlink/mavlink_ftp.h
+++ b/src/modules/mavlink/mavlink_ftp.h
@@ -33,17 +33,8 @@
 
 #pragma once
 
-/**
- * @file mavlink_ftp.h
- *
- * MAVLink remote file server.
- *
- * A limited number of requests (currently 2) may be outstanding at a time.
- * Additional messages will be discarded.
- *
- * Messages consist of a fixed header, followed by a data area.
- *
- */
+/// @file mavlink_ftp.h
+///     @author px4dev, Don Gagne <don@thegagnes.com>
  
 #include <dirent.h>
 #include <queue.h>
@@ -54,183 +45,128 @@
 #include "mavlink_messages.h"
 #include "mavlink_main.h"
 
+class MavlinkFtpTest;
+
+/// @brief MAVLink remote file server. Support FTP like commands using MAVLINK_MSG_ID_FILE_TRANSFER_PROTOCOL message.
+/// A limited number of requests (kRequestQueueSize) may be outstanding at a time. Additional messages will be discarded.
 class MavlinkFTP
 {
 public:
+	/// @brief Returns the one Mavlink FTP server in the system.
+	static MavlinkFTP* get_server(void);
+    
+	/// @brief Contructor is only public so unit test code can new objects.
 	MavlinkFTP();
-
-	static MavlinkFTP	*getServer();
-
-	// static interface
-	void			handle_message(Mavlink* mavlink,
-					mavlink_message_t *msg);
-
-private:
-
-	static const unsigned	kRequestQueueSize = 2;
-
-	static MavlinkFTP	*_server;
-
-	/// @brief Trying to pack structures across differing compilers is questionable for Clients, so we pad the
-	/// structure ourselves to 32 bit alignment which should get us what we want.
-	struct RequestHeader
+	
+	/// @brief Adds the specified message to the work queue.
+	void handle_message(Mavlink* mavlink, mavlink_message_t *msg);
+    
+	typedef void (*ReceiveMessageFunc_t)(const mavlink_message_t *msg, MavlinkFtpTest* ftpTest);
+	
+	/// @brief Sets up the server to run in unit test mode.
+	///	@param rcvmsgFunc Function which will be called to handle outgoing mavlink messages.
+	///	@param ftp_test MavlinkFtpTest object which the function is associated with
+	void set_unittest_worker(ReceiveMessageFunc_t rcvMsgFunc, MavlinkFtpTest *ftp_test);
+
+	/// @brief This is the payload which is in mavlink_file_transfer_protocol_t.payload. We pad the structure ourselves to
+	/// 32 bit alignment to avoid usage of any pack pragmas.
+	struct PayloadHeader
         {
-		uint16_t	seqNumber;  ///< sequence number for message
-		uint8_t		session;    ///< Session id for read and write commands
-		uint8_t		opcode;     ///< Command opcode
-		uint8_t		size;       ///< Size of data
-		uint8_t		padding[3];
-		uint32_t	crc32;      ///< CRC for entire Request structure, with crc32 and padding set to 0
-		uint32_t	offset;     ///< Offsets for List and Read commands
-		uint8_t		data[];
+		uint16_t	seqNumber;	///< sequence number for message
+		uint8_t		session;	///< Session id for read and write commands
+		uint8_t		opcode;		///< Command opcode
+		uint8_t		size;		///< Size of data
+		uint8_t		req_opcode;	///< Request opcode returned in kRspAck, kRspNak message
+		uint8_t		padding[2];	///< 32 bit aligment padding
+		uint32_t	offset;		///< Offsets for List and Read commands
+		uint8_t		data[];		///< command data, varies by Opcode
         };
-
+	
+	/// @brief Command opcodes
 	enum Opcode : uint8_t
 	{
-		kCmdNone,	// ignored, always acked
-		kCmdTerminate,	// releases sessionID, closes file
-		kCmdReset,	// terminates all sessions
-		kCmdList,	// list files in <path> from <offset>
-		kCmdOpen,	// opens <path> for reading, returns <session>
-		kCmdRead,	// reads <size> bytes from <offset> in <session>
-		kCmdCreate,	// creates <path> for writing, returns <session>
-		kCmdWrite,	// appends <size> bytes at <offset> in <session>
-		kCmdRemove,	// remove file (only if created by server?)
-
-		kRspAck,
-		kRspNak
+		kCmdNone,		///< ignored, always acked
+		kCmdTerminateSession,	///< Terminates open Read session
+		kCmdResetSessions,	///< Terminates all open Read sessions
+		kCmdListDirectory,	///< List files in <path> from <offset>
+		kCmdOpenFile,		///< Opens file at <path> for reading, returns <session>
+		kCmdReadFile,		///< Reads <size> bytes from <offset> in <session>
+		kCmdCreateFile,		///< Creates file at <path> for writing, returns <session>
+		kCmdWriteFile,		///< Appends <size> bytes to file in <session>
+		kCmdRemoveFile,		///< Remove file at <path>
+		kCmdCreateDirectory,	///< Creates directory at <path>
+		kCmdRemoveDirectory,	///< Removes Directory at <path>, must be empty
+		
+		kRspAck = 128,		///< Ack response
+		kRspNak			///< Nak response
 	};
-
+	
+	/// @brief Error codes returned in Nak response PayloadHeader.data[0].
 	enum ErrorCode : uint8_t
-	{
+        {
 		kErrNone,
-		kErrNoRequest,
-		kErrNoSession,
-		kErrSequence,
-		kErrNotDir,
-		kErrNotFile,
-		kErrEOF,
-		kErrNotAppend,
-		kErrTooBig,
-		kErrIO,
-		kErrPerm
-	};
-
-    int _findUnusedSession(void);
-    bool _validSession(unsigned index);
-
-    static const unsigned kMaxSession = 2;
-    int	_session_fds[kMaxSession];
-
-	class Request
+		kErrFail,			///< Unknown failure
+		kErrFailErrno,			///< Command failed, errno sent back in PayloadHeader.data[1]
+		kErrInvalidDataSize,		///< PayloadHeader.size is invalid
+		kErrInvalidSession,		///< Session is not currently open
+		kErrNoSessionsAvailable,	///< All available Sessions in use
+		kErrEOF,			///< Offset past end of file for List and Read commands
+		kErrUnknownCommand		///< Unknown command opcode
+        };
+	
+private:
+	/// @brief Unit of work which is queued to work_queue
+	struct Request
 	{
-	public:
-		union {
-			dq_entry_t	entry;
-			work_s		work;
-		};
-
-		bool		decode(Mavlink *mavlink, mavlink_message_t *fromMessage) {
-			if (fromMessage->msgid == MAVLINK_MSG_ID_FILE_TRANSFER_PROTOCOL) {
-				_systemId = fromMessage->sysid;
-				_mavlink = mavlink;
-				mavlink_msg_file_transfer_protocol_decode(fromMessage, &_message);
-				return _message.target_system == _mavlink->get_system_id();
-			}
-			return false;
-		}
-
-		void		reply() {
-
-			// XXX the proper way would be an IOCTL / uORB call, rather than exploiting the
-			// flat memory architecture, as we're operating between threads here.
-			mavlink_message_t msg;
-			msg.checksum = 0;
-			unsigned len = mavlink_msg_file_transfer_protocol_pack_chan(_mavlink->get_system_id(),		// Sender system id
-										    _mavlink->get_component_id(),	// Sender component id
-										    _mavlink->get_channel(),		// Channel to send on
-										    &msg,				// Message to pack payload into
-										    0,					// Target network
-										    _systemId,				// Target system id
-										    0,					// Target component id
-										    rawData());				// Payload to pack into message
-
-			_mavlink->lockMessageBufferMutex();
-			bool success = _mavlink->message_buffer_write(&msg, len);
-			_mavlink->unlockMessageBufferMutex();
-
-			if (!success) {
-				warnx("FTP TX ERR");
-			}
-#ifdef MAVLINK_FTP_DEBUG
-			else {
-				warnx("wrote: sys: %d, comp: %d, chan: %d, len: %d, checksum: %d",
-				      _mavlink->get_system_id(),
-				      _mavlink->get_component_id(),
-				      _mavlink->get_channel(),
-				      len,
-				      msg.checksum);
-			}
-#endif
-		}
-
-		uint8_t		*rawData() { return &_message.payload[0]; }
-		RequestHeader 	*header()  { return reinterpret_cast<RequestHeader *>(&_message.payload[0]); }
-		uint8_t         *requestData() { return &(header()->data[0]); }
-		unsigned	dataSize() { return header()->size + sizeof(RequestHeader); }
-		mavlink_channel_t channel() { return _mavlink->get_channel(); }
-
-		char		*dataAsCString();
-
-	private:
-		Mavlink			*_mavlink;
-		mavlink_file_transfer_protocol_t _message;
-		uint8_t _systemId;
-
+		work_s	work;			///< work queue entry
+		Mavlink	*mavlink;		///< Mavlink to reply to
+		uint8_t serverSystemId;		///< System ID to send from
+		uint8_t serverComponentId;	///< Component ID to send from
+		uint8_t serverChannel;		///< Channel to send to
+		uint8_t targetSystemId;		///< System ID to target reply to
+
+		mavlink_file_transfer_protocol_t message;	///< Protocol message
 	};
-
-	static const char	kDirentFile = 'F';
-	static const char	kDirentDir = 'D';
-	static const char	kDirentUnknown = 'U';
-	static const uint8_t	kMaxDataLength = MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(RequestHeader);
-
-	/// Request worker; runs on the low-priority work queue to service
-	/// remote requests.
-	///
-	static void		_workerTrampoline(void *arg);
-	void			_worker(Request *req);
-
-	/// Reply to a request (XXX should be a Request method)
-	///
-	void			_reply(Request *req);
-
-	ErrorCode		_workList(Request *req);
-	ErrorCode		_workOpen(Request *req, bool create);
-	ErrorCode		_workRead(Request *req);
-	ErrorCode		_workWrite(Request *req);
-	ErrorCode		_workRemove(Request *req);
-	ErrorCode		_workTerminate(Request *req);
-	ErrorCode		_workReset();
-
-	// work freelist
-	Request			_workBufs[kRequestQueueSize];
-	dq_queue_t		_workFree;
-	sem_t			_lock;
-
-	void			_qLock() { do {} while (sem_wait(&_lock) != 0); }
-	void			_qUnlock() { sem_post(&_lock); }
-
-	void			_qFree(Request *req) {
-		_qLock();
-		dq_addlast(&req->entry, &_workFree);
-		_qUnlock();
-	}
-
-	Request			*_dqFree() {
-		_qLock();
-		auto req = reinterpret_cast<Request *>(dq_remfirst(&_workFree));
-		_qUnlock();
-		return req;
-	}
-    
+	
+	Request		*_get_request(void);
+	void		_return_request(Request *req);
+	void		_lock_request_queue(void);
+	void		_unlock_request_queue(void);
+	
+	char		*_data_as_cstring(PayloadHeader* payload);
+	
+	static void	_worker_trampoline(void *arg);
+	void		_process_request(Request *req);
+	void		_reply(Request *req);
+
+	ErrorCode	_workList(PayloadHeader *payload);
+	ErrorCode	_workOpen(PayloadHeader *payload, bool create);
+	ErrorCode	_workRead(PayloadHeader *payload);
+	ErrorCode	_workWrite(PayloadHeader *payload);
+	ErrorCode	_workTerminate(PayloadHeader *payload);
+	ErrorCode	_workReset(PayloadHeader* payload);
+	ErrorCode	_workRemoveDirectory(PayloadHeader *payload);
+	ErrorCode	_workCreateDirectory(PayloadHeader *payload);
+	ErrorCode	_workRemoveFile(PayloadHeader *payload);
+
+	static const unsigned	kRequestQueueSize = 2;			///< Max number of queued requests
+	Request			_request_bufs[kRequestQueueSize];	///< Request buffers which hold work
+	dq_queue_t		_request_queue;				///< Queue of available Request buffers
+	sem_t			_request_queue_sem;			///< Semaphore for locking access to _request_queue
+	
+	int _find_unused_session(void);
+	bool _valid_session(unsigned index);
+	
+	static const char	kDirentFile = 'F';	///< Identifies File returned from List command
+	static const char	kDirentDir = 'D';	///< Identifies Directory returned from List command
+	static const char	kDirentSkip = 'S';	///< Identifies Skipped entry from List command
+	
+	/// @brief Maximum data size in RequestHeader::data
+	static const uint8_t	kMaxDataLength = MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(PayloadHeader);
+	
+	static const unsigned kMaxSession = 2;	///< Max number of active sessions
+	int	_session_fds[kMaxSession];	///< Session file descriptors, 0 for empty slot
+	
+	ReceiveMessageFunc_t _utRcvMsgFunc;	///< Unit test override for mavlink message sending
+	MavlinkFtpTest *_ftp_test;		///< Additional parameter to _utRcvMsgFunc;
 };
diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp
index 1115304d4..373d06d4d 100644
--- a/src/modules/mavlink/mavlink_receiver.cpp
+++ b/src/modules/mavlink/mavlink_receiver.cpp
@@ -123,7 +123,7 @@ MavlinkReceiver::MavlinkReceiver(Mavlink *parent) :
 {
 
 	// make sure the FTP server is started
-	(void)MavlinkFTP::getServer();
+	(void)MavlinkFTP::get_server();
 }
 
 MavlinkReceiver::~MavlinkReceiver()
@@ -175,7 +175,7 @@ MavlinkReceiver::handle_message(mavlink_message_t *msg)
 		break;
 
 	case MAVLINK_MSG_ID_FILE_TRANSFER_PROTOCOL:
-		MavlinkFTP::getServer()->handle_message(_mavlink, msg);
+		MavlinkFTP::get_server()->handle_message(_mavlink, msg);
 		break;
 
 	default:
diff --git a/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp
new file mode 100644
index 000000000..022041c74
--- /dev/null
+++ b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp
@@ -0,0 +1,757 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 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 mavlink_ftp_test.cpp
+///	@author Don Gagne <don@thegagnes.com>
+
+#include <sys/stat.h>
+#include <crc32.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#include "mavlink_ftp_test.h"
+#include "../mavlink_ftp.h"
+
+/// @brief Test case file name for Read command. File are generated using mavlink_ftp_test_data.py
+const MavlinkFtpTest::ReadTestCase MavlinkFtpTest::_rgReadTestCases[] = {
+	{ "/etc/unit_test_data/mavlink_tests/test_238.data",	MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(MavlinkFTP::PayloadHeader) - 1},	// Read takes less than single packet
+	{ "/etc/unit_test_data/mavlink_tests/test_239.data",	MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(MavlinkFTP::PayloadHeader) },		// Read completely fills single packet
+	{ "/etc/unit_test_data/mavlink_tests/test_240.data",	MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(MavlinkFTP::PayloadHeader) + 1 },	// Read take two packets
+};
+
+const char MavlinkFtpTest::_unittest_microsd_dir[] = "/fs/microsd/ftp_unit_test_dir";
+const char MavlinkFtpTest::_unittest_microsd_file[] = "/fs/microsd/ftp_unit_test_dir/file";
+
+MavlinkFtpTest::MavlinkFtpTest() :
+	_ftp_server{},
+	_reply_msg{},
+	_lastOutgoingSeqNumber{}
+{
+}
+
+MavlinkFtpTest::~MavlinkFtpTest()
+{
+	
+}
+
+/// @brief Called before every test to initialize the FTP Server.
+void MavlinkFtpTest::init(void)
+{
+	_ftp_server = new MavlinkFTP;;
+	_ftp_server->set_unittest_worker(MavlinkFtpTest::receive_message, this);
+
+	_cleanup_microsd();
+}
+
+/// @brief Called after every test to take down the FTP Server.
+void MavlinkFtpTest::cleanup(void)
+{
+	delete _ftp_server;
+	
+	_cleanup_microsd();
+}
+
+/// @brief Tests for correct behavior of an Ack response.
+bool MavlinkFtpTest::_ack_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	payload.opcode = MavlinkFTP::kCmdNone;
+
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					 0,		// size in bytes of data
+					 nullptr,	// Data to start into FTP message payload
+					 &ftp_msg,	// Response from server
+					 &reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+	ut_compare("Incorrect payload size", reply->size, 0);
+	
+	return true;
+}
+
+/// @brief Tests for correct response to an invalid opcpde.
+bool MavlinkFtpTest::_bad_opcode_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	payload.opcode = 0xFF;	// bogus opcode
+
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					 0,		// size in bytes of data
+					 nullptr,	// Data to start into FTP message payload
+					 &ftp_msg,	// Response from server
+					 &reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 1);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrUnknownCommand);
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to a payload which an invalid data size field.
+bool MavlinkFtpTest::_bad_datasize_test(void)
+{
+	mavlink_message_t			msg;
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	payload.opcode = MavlinkFTP::kCmdListDirectory;
+	
+	_setup_ftp_msg(&payload, 0, nullptr, &msg);
+	
+	// Set the data size to be one larger than is legal
+	((MavlinkFTP::PayloadHeader*)((mavlink_file_transfer_protocol_t*)msg.payload64)->payload)->size = MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN + 1;
+	
+	_ftp_server->handle_message(nullptr /* mavlink */, &msg);
+	
+	if (!_decode_message(&_reply_msg, &ftp_msg, &reply)) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 1);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrInvalidDataSize);
+	
+	return true;
+}
+
+bool MavlinkFtpTest::_list_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	char response1[] = "Dempty_dir|Ftest_238.data\t238|Ftest_239.data\t239|Ftest_240.data\t240";
+	char response2[] = "Ddev|Detc|Dfs|Dobj";
+	
+	struct _testCase {
+		const char	*dir;		///< Directory to run List command on
+		char		*response;	///< Expected response entries from List command
+		int		response_count;	///< Number of directories that should be returned
+		bool		success;	///< true: List command should succeed, false: List command should fail
+	};
+	struct _testCase rgTestCases[] = {
+		{ "/bogus",				nullptr,	0,	false },
+		{ "/etc/unit_test_data/mavlink_tests",	response1,	4,	true },
+		{ "/",					response2,	4,	true },
+	};
+
+	for (size_t i=0; i<sizeof(rgTestCases)/sizeof(rgTestCases[0]); i++) {
+		const struct _testCase *test = &rgTestCases[i];
+		
+		payload.opcode = MavlinkFTP::kCmdListDirectory;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						strlen(test->dir)+1,	// size in bytes of data
+						(uint8_t*)test->dir,	// Data to start into FTP message payload
+						&ftp_msg,		// Response from server
+						&reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		if (test->success) {
+			ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+			ut_compare("Incorrect payload size", reply->size, strlen(test->response) + 1);
+			
+			// The return order of directories from the List command is not repeatable. So we can't do a direct comparison
+			// to a hardcoded return result string.
+			
+			// Convert null terminators to seperator char so we can use strok to parse returned data
+			for (uint8_t j=0; j<reply->size-1; j++) {
+				if (reply->data[j] == 0) {
+					reply->data[j] = '|';
+				}
+			}
+			
+			// Loop over returned directory entries trying to find then in the response list
+			char *dir;
+			int response_count = 0;
+			dir = strtok((char *)&reply->data[0], "|");
+			while (dir != nullptr) {
+				ut_assert("Returned directory not found in expected response", strstr(test->response, dir));
+				response_count++;
+				dir = strtok(nullptr, "|");
+			}
+			
+			ut_compare("Incorrect number of directory entires returned", test->response_count, response_count);
+		} else {
+			ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+			ut_compare("Incorrect payload size", reply->size, 2);
+			ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrFailErrno);
+		}
+	}
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to a List command on a valid directory, but with an offset that
+/// is beyond the last directory entry.
+bool MavlinkFtpTest::_list_eof_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	const char				*dir = "/";
+	
+	payload.opcode = MavlinkFTP::kCmdListDirectory;
+	payload.offset = 4;	// offset past top level dirs
+	
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					strlen(dir)+1,	// size in bytes of data
+					(uint8_t*)dir,	// Data to start into FTP message payload
+					&ftp_msg,	// Response from server
+					&reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 1);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrEOF);
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to an Open command on a file which does not exist.
+bool MavlinkFtpTest::_open_badfile_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	const char				*dir = "/foo";	// non-existent file
+	
+	payload.opcode = MavlinkFTP::kCmdOpenFile;
+	payload.offset = 0;
+	
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					strlen(dir)+1,	// size in bytes of data
+					(uint8_t*)dir,	// Data to start into FTP message payload
+					&ftp_msg,	// Response from server
+					&reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 2);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrFailErrno);
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to an Open command on a file, followed by Terminate
+bool MavlinkFtpTest::_open_terminate_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	for (size_t i=0; i<sizeof(_rgReadTestCases)/sizeof(_rgReadTestCases[0]); i++) {
+		struct stat st;
+		const ReadTestCase *test = &_rgReadTestCases[i];
+		
+		payload.opcode = MavlinkFTP::kCmdOpenFile;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						 strlen(test->file)+1,	// size in bytes of data
+						 (uint8_t*)test->file,	// Data to start into FTP message payload
+						 &ftp_msg,		// Response from server
+						 &reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		ut_compare("stat failed", stat(test->file, &st), 0);
+		
+		
+		ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+		ut_compare("Incorrect payload size", reply->size, sizeof(uint32_t));
+		ut_compare("File size incorrect", *((uint32_t*)&reply->data[0]), (uint32_t)st.st_size);
+
+		payload.opcode = MavlinkFTP::kCmdTerminateSession;
+		payload.session = reply->session;
+		payload.size = 0;
+		
+		success = _send_receive_msg(&payload,	// FTP payload header
+					    0,		// size in bytes of data
+					    nullptr,	// Data to start into FTP message payload
+					    &ftp_msg,	// Response from server
+					    &reply);	// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+		ut_compare("Incorrect payload size", reply->size, 0);
+	}
+
+	return true;
+}
+
+/// @brief Tests for correct reponse to a Terminate command on an invalid session.
+bool MavlinkFtpTest::_terminate_badsession_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	const char				*file = _rgReadTestCases[0].file;
+	
+	payload.opcode = MavlinkFTP::kCmdOpenFile;
+	payload.offset = 0;
+	
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					strlen(file)+1,	// size in bytes of data
+					(uint8_t*)file,	// Data to start into FTP message payload
+					&ftp_msg,	// Response from server
+					&reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+	
+	payload.opcode = MavlinkFTP::kCmdTerminateSession;
+	payload.session = reply->session + 1;
+	payload.size = 0;
+	
+	success = _send_receive_msg(&payload,	// FTP payload header
+				   0,		// size in bytes of data
+				   nullptr,	// Data to start into FTP message payload
+				   &ftp_msg,	// Response from server
+				   &reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 1);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrInvalidSession);
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to a Read command on an open session.
+bool MavlinkFtpTest::_read_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	for (size_t i=0; i<sizeof(_rgReadTestCases)/sizeof(_rgReadTestCases[0]); i++) {
+		struct stat st;
+		const ReadTestCase *test = &_rgReadTestCases[i];
+		
+		// Read in the file so we can compare it to what we get back
+		ut_compare("stat failed", stat(test->file, &st), 0);
+		uint8_t *bytes = new uint8_t[st.st_size];
+		ut_assert("new failed", bytes != nullptr);
+		int fd = ::open(test->file, O_RDONLY);
+		ut_assert("open failed", fd != -1);
+		int bytes_read = ::read(fd, bytes, st.st_size);
+		ut_compare("read failed", bytes_read, st.st_size);
+		::close(fd);
+		
+		// Test case data files are created for specific boundary conditions
+		ut_compare("Test case data files are out of date", test->length, st.st_size);
+		
+		payload.opcode = MavlinkFTP::kCmdOpenFile;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						 strlen(test->file)+1,	// size in bytes of data
+						 (uint8_t*)test->file,	// Data to start into FTP message payload
+						 &ftp_msg,		// Response from server
+						 &reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+		
+		payload.opcode = MavlinkFTP::kCmdReadFile;
+		payload.session = reply->session;
+		payload.offset = 0;
+		
+		success = _send_receive_msg(&payload,	// FTP payload header
+					    0,		// size in bytes of data
+					    nullptr,	// Data to start into FTP message payload
+					    &ftp_msg,	// Response from server
+					    &reply);	// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+		ut_compare("Offset incorrect", reply->offset, 0);
+		
+		if (test->length <= MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN - sizeof(MavlinkFTP::PayloadHeader)) {
+			ut_compare("Payload size incorrect", reply->size, (uint32_t)st.st_size);
+			ut_compare("File contents differ", memcmp(reply->data, bytes, st.st_size), 0);
+		}
+		
+		payload.opcode = MavlinkFTP::kCmdTerminateSession;
+		payload.session = reply->session;
+		payload.size = 0;
+		
+		success = _send_receive_msg(&payload,	// FTP payload header
+					    0,		// size in bytes of data
+					    nullptr,	// Data to start into FTP message payload
+					    &ftp_msg,	// Response from server
+					    &reply);	// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+		ut_compare("Incorrect payload size", reply->size, 0);
+	}
+	
+	return true;
+}
+
+/// @brief Tests for correct reponse to a Read command on an invalid session.
+bool MavlinkFtpTest::_read_badsession_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	const char				*file = _rgReadTestCases[0].file;
+	
+	payload.opcode = MavlinkFTP::kCmdOpenFile;
+	payload.offset = 0;
+	
+	bool success = _send_receive_msg(&payload,	// FTP payload header
+					 strlen(file)+1,	// size in bytes of data
+					 (uint8_t*)file,	// Data to start into FTP message payload
+					 &ftp_msg,	// Response from server
+					 &reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+	
+	payload.opcode = MavlinkFTP::kCmdReadFile;
+	payload.session = reply->session + 1;	// Invalid session
+	payload.offset = 0;
+	
+	success = _send_receive_msg(&payload,	// FTP payload header
+				    0,		// size in bytes of data
+				    nullptr,	// Data to start into FTP message payload
+				    &ftp_msg,	// Response from server
+				    &reply);	// Payload inside FTP message response
+	if (!success) {
+		return false;
+	}
+	
+	ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+	ut_compare("Incorrect payload size", reply->size, 1);
+	ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrInvalidSession);
+	
+	return true;
+}
+
+bool MavlinkFtpTest::_removedirectory_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	int					fd;
+	
+	struct _testCase {
+		const char	*dir;
+		bool		success;
+		bool		deleteFile;
+	};
+	static const struct _testCase rgTestCases[] = {
+		{ "/bogus",						false,	false },
+		{ "/etc/unit_test_data/mavlink_tests/empty_dir",	false,	false },
+		{ _unittest_microsd_dir,				false,	false },
+		{ _unittest_microsd_file,				false,	false },
+		{ _unittest_microsd_dir,				true,	true },
+	};
+	
+	ut_compare("mkdir failed", ::mkdir(_unittest_microsd_dir, S_IRWXU | S_IRWXG | S_IRWXO), 0);
+	ut_assert("open failed", (fd = ::open(_unittest_microsd_file, O_CREAT | O_EXCL)) != -1);
+	::close(fd);
+	
+	for (size_t i=0; i<sizeof(rgTestCases)/sizeof(rgTestCases[0]); i++) {
+		const struct _testCase *test = &rgTestCases[i];
+		
+		if (test->deleteFile) {
+			ut_compare("unlink failed", ::unlink(_unittest_microsd_file), 0);
+		}
+		
+		payload.opcode = MavlinkFTP::kCmdRemoveDirectory;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						 strlen(test->dir)+1,	// size in bytes of data
+						 (uint8_t*)test->dir,	// Data to start into FTP message payload
+						 &ftp_msg,		// Response from server
+						 &reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		if (test->success) {
+			ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+			ut_compare("Incorrect payload size", reply->size, 0);
+		} else {
+			ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+			ut_compare("Incorrect payload size", reply->size, 2);
+			ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrFailErrno);
+		}
+	}
+	
+	return true;
+}
+
+bool MavlinkFtpTest::_createdirectory_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	
+	struct _testCase {
+		const char	*dir;
+		bool		success;
+	};
+	static const struct _testCase rgTestCases[] = {
+		{ "/etc/bogus",			false },
+		{ _unittest_microsd_dir,	true },
+		{ _unittest_microsd_dir,	false },
+		{ "/fs/microsd/bogus/bogus",	false },
+	};
+	
+	for (size_t i=0; i<sizeof(rgTestCases)/sizeof(rgTestCases[0]); i++) {
+		const struct _testCase *test = &rgTestCases[i];
+		
+		payload.opcode = MavlinkFTP::kCmdCreateDirectory;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						 strlen(test->dir)+1,	// size in bytes of data
+						 (uint8_t*)test->dir,	// Data to start into FTP message payload
+						 &ftp_msg,		// Response from server
+						 &reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		if (test->success) {
+			ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+			ut_compare("Incorrect payload size", reply->size, 0);
+		} else {
+			ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+			ut_compare("Incorrect payload size", reply->size, 2);
+			ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrFailErrno);
+		}
+	}
+	
+	return true;
+}
+
+bool MavlinkFtpTest::_removefile_test(void)
+{
+	MavlinkFTP::PayloadHeader		payload;
+	mavlink_file_transfer_protocol_t	ftp_msg;
+	MavlinkFTP::PayloadHeader		*reply;
+	int					fd;
+	
+	struct _testCase {
+		const char	*file;
+		bool		success;
+	};
+	static const struct _testCase rgTestCases[] = {
+		{ "/bogus",			false },
+		{ _rgReadTestCases[0].file,	false },
+		{ _unittest_microsd_dir,	false },
+		{ _unittest_microsd_file,	true },
+		{ _unittest_microsd_file,	false },
+	};
+	
+	ut_compare("mkdir failed", ::mkdir(_unittest_microsd_dir, S_IRWXU | S_IRWXG | S_IRWXO), 0);
+	ut_assert("open failed", (fd = ::open(_unittest_microsd_file, O_CREAT | O_EXCL)) != -1);
+	::close(fd);
+	
+	for (size_t i=0; i<sizeof(rgTestCases)/sizeof(rgTestCases[0]); i++) {
+		const struct _testCase *test = &rgTestCases[i];
+		
+		payload.opcode = MavlinkFTP::kCmdRemoveFile;
+		payload.offset = 0;
+		
+		bool success = _send_receive_msg(&payload,		// FTP payload header
+						 strlen(test->file)+1,	// size in bytes of data
+						 (uint8_t*)test->file,	// Data to start into FTP message payload
+						 &ftp_msg,		// Response from server
+						 &reply);		// Payload inside FTP message response
+		if (!success) {
+			return false;
+		}
+		
+		if (test->success) {
+			ut_compare("Didn't get Ack back", reply->opcode, MavlinkFTP::kRspAck);
+			ut_compare("Incorrect payload size", reply->size, 0);
+		} else {
+			ut_compare("Didn't get Nak back", reply->opcode, MavlinkFTP::kRspNak);
+			ut_compare("Incorrect payload size", reply->size, 2);
+			ut_compare("Incorrect error code", reply->data[0], MavlinkFTP::kErrFailErrno);
+		}
+	}
+	
+	return true;
+}
+
+/// @brief Static method used as callback from MavlinkFTP. This method will be called by MavlinkFTP when
+/// it needs to send a message out on Mavlink.
+void MavlinkFtpTest::receive_message(const mavlink_message_t *msg, MavlinkFtpTest *ftp_test)
+{
+	ftp_test->_receive_message(msg);
+}
+
+/// @brief Non-Static version of receive_message
+void MavlinkFtpTest::_receive_message(const mavlink_message_t *msg)
+{
+	// Move the message into our own member variable
+	memcpy(&_reply_msg, msg, sizeof(mavlink_message_t));
+}
+
+/// @brief Decode and validate the incoming message
+bool MavlinkFtpTest::_decode_message(const mavlink_message_t		*msg,		///< Mavlink message to decode
+				     mavlink_file_transfer_protocol_t	*ftp_msg,	///< Decoded FTP message
+				     MavlinkFTP::PayloadHeader		**payload)	///< Payload inside FTP message response
+{
+	mavlink_msg_file_transfer_protocol_decode(msg, ftp_msg);
+	
+	// Make sure the targets are correct
+	ut_compare("Target network non-zero", ftp_msg->target_network, 0);
+	ut_compare("Target system id mismatch", ftp_msg->target_system, clientSystemId);
+	ut_compare("Target component id mismatch", ftp_msg->target_component, clientComponentId);
+	
+	*payload = reinterpret_cast<MavlinkFTP::PayloadHeader *>(ftp_msg->payload);
+	
+	// Make sure we have a good sequence number
+	ut_compare("Sequence number mismatch", (*payload)->seqNumber, _lastOutgoingSeqNumber + 1);
+	
+	// Bump sequence number for next outgoing message
+	_lastOutgoingSeqNumber++;
+	
+	return true;
+}
+
+/// @brief Initializes an FTP message into a mavlink message
+void MavlinkFtpTest::_setup_ftp_msg(MavlinkFTP::PayloadHeader	*payload_header,	///< FTP payload header
+				    uint8_t			size,			///< size in bytes of data
+				    const uint8_t		*data,			///< Data to start into FTP message payload
+				    mavlink_message_t		*msg)			///< Returned mavlink message
+{
+	uint8_t payload_bytes[MAVLINK_MSG_FILE_TRANSFER_PROTOCOL_FIELD_PAYLOAD_LEN];
+	MavlinkFTP::PayloadHeader *payload = reinterpret_cast<MavlinkFTP::PayloadHeader *>(payload_bytes);
+			     
+	memcpy(payload, payload_header, sizeof(MavlinkFTP::PayloadHeader));
+	
+	payload->seqNumber = _lastOutgoingSeqNumber;
+	payload->size = size;
+	if (size != 0) {
+		memcpy(payload->data, data, size);
+	}
+    
+	payload->padding[0] = 0;
+	payload->padding[1] = 0;
+	
+	msg->checksum = 0;
+	mavlink_msg_file_transfer_protocol_pack(clientSystemId,		// Sender system id
+						clientComponentId,	// Sender component id
+						msg,			// Message to pack payload into
+						0,			// Target network
+						serverSystemId,		// Target system id
+						serverComponentId,	// Target component id
+						payload_bytes);		// Payload to pack into message
+}
+
+/// @brief Sends the specified FTP message to the server and returns response
+bool MavlinkFtpTest::_send_receive_msg(MavlinkFTP::PayloadHeader	*payload_header,	///< FTP payload header
+				      uint8_t				size,			///< size in bytes of data
+				      const uint8_t			*data,			///< Data to start into FTP message payload
+				      mavlink_file_transfer_protocol_t	*ftp_msg_reply,		///< Response from server
+				      MavlinkFTP::PayloadHeader		**payload_reply)	///< Payload inside FTP message response
+{
+	mavlink_message_t msg;
+
+	_setup_ftp_msg(payload_header, size, data, &msg);
+	_ftp_server->handle_message(nullptr /* mavlink */, &msg);
+	return _decode_message(&_reply_msg, ftp_msg_reply, payload_reply);
+}
+	
+/// @brief Cleans up an files created on microsd during testing
+void MavlinkFtpTest::_cleanup_microsd(void)
+{
+	::unlink(_unittest_microsd_file);
+	::rmdir(_unittest_microsd_dir);
+}
+
+/// @brief Runs all the unit tests
+void MavlinkFtpTest::runTests(void)
+{
+	ut_run_test(_ack_test);
+	ut_run_test(_bad_opcode_test);
+	ut_run_test(_bad_datasize_test);
+	ut_run_test(_list_test);
+	ut_run_test(_list_eof_test);
+	ut_run_test(_open_badfile_test);
+	ut_run_test(_open_terminate_test);
+	ut_run_test(_terminate_badsession_test);
+	ut_run_test(_read_test);
+	ut_run_test(_read_badsession_test);
+	ut_run_test(_removedirectory_test);
+	ut_run_test(_createdirectory_test);
+	ut_run_test(_removefile_test);
+}
+
diff --git a/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.h b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.h
new file mode 100644
index 000000000..babd909da
--- /dev/null
+++ b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.h
@@ -0,0 +1,107 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 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 mavlink_ftp_test.h
+///	@author Don Gagne <don@thegagnes.com>
+
+#pragma once
+
+#include <unit_test/unit_test.h>
+#include "../mavlink_bridge_header.h"
+#include "../mavlink_ftp.h"
+
+class MavlinkFtpTest : public UnitTest
+{
+public:
+	MavlinkFtpTest();
+	virtual ~MavlinkFtpTest();
+	
+	virtual void init(void);
+	virtual void cleanup(void);
+	
+	virtual void runTests(void);
+	
+	static void receive_message(const mavlink_message_t *msg, MavlinkFtpTest* ftpTest);
+	
+	static const uint8_t serverSystemId = 50;	///< System ID for server
+	static const uint8_t serverComponentId = 1;	///< Component ID for server
+	static const uint8_t serverChannel = 0;		///< Channel to send to
+	
+	static const uint8_t clientSystemId = 1;	///< System ID for client
+	static const uint8_t clientComponentId = 0;	///< Component ID for client
+	
+	// We don't want any of these
+	MavlinkFtpTest(const MavlinkFtpTest&);
+	MavlinkFtpTest& operator=(const MavlinkFtpTest&);
+	
+private:
+	bool _ack_test(void);
+	bool _bad_opcode_test(void);
+	bool _bad_datasize_test(void);
+	bool _list_test(void);
+	bool _list_eof_test(void);
+	bool _open_badfile_test(void);
+	bool _open_terminate_test(void);
+	bool _terminate_badsession_test(void);
+	bool _read_test(void);
+	bool _read_badsession_test(void);
+	bool _removedirectory_test(void);
+	bool _createdirectory_test(void);
+	bool _removefile_test(void);
+	
+	void _receive_message(const mavlink_message_t *msg);
+	void _setup_ftp_msg(MavlinkFTP::PayloadHeader *payload_header, uint8_t size, const uint8_t *data, mavlink_message_t *msg);
+	bool _decode_message(const mavlink_message_t *msg, mavlink_file_transfer_protocol_t *ftp_msg, MavlinkFTP::PayloadHeader **payload);
+	bool _send_receive_msg(MavlinkFTP::PayloadHeader	*payload_header,
+                           uint8_t				size,
+                           const uint8_t			*data,
+                           mavlink_file_transfer_protocol_t	*ftp_msg_reply,
+                           MavlinkFTP::PayloadHeader		**payload_reply);
+	void _cleanup_microsd(void);
+	
+	MavlinkFTP *_ftp_server;
+    
+	mavlink_message_t _reply_msg;
+    
+	uint16_t _lastOutgoingSeqNumber;
+	
+	struct ReadTestCase {
+		const char	*file;
+		const uint16_t	length;
+	};
+	static const ReadTestCase _rgReadTestCases[];
+	
+	static const char _unittest_microsd_dir[];
+	static const char _unittest_microsd_file[];
+};
+
diff --git a/src/modules/mavlink/mavlink_tests/mavlink_ftp_test_data.py b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test_data.py
new file mode 100644
index 000000000..a7e68f2a3
--- /dev/null
+++ b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test_data.py
@@ -0,0 +1,7 @@
+import sys
+print 'Arguments: file - ' + sys.argv[1] + ', length - ' + sys.argv[2]
+file = open(sys.argv[1], 'w')
+for i in range(int(sys.argv[2])):
+	b = bytearray([i & 0xFF])
+	file.write(b)
+file.close()
\ No newline at end of file
diff --git a/src/modules/mavlink/mavlink_tests/mavlink_tests.cpp b/src/modules/mavlink/mavlink_tests/mavlink_tests.cpp
new file mode 100644
index 000000000..d9c1e413a
--- /dev/null
+++ b/src/modules/mavlink/mavlink_tests/mavlink_tests.cpp
@@ -0,0 +1,52 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 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 mavlink_ftp_tests.cpp
+ */
+
+#include <systemlib/err.h>
+
+#include "mavlink_ftp_test.h"
+
+extern "C" __EXPORT int mavlink_tests_main(int argc, char *argv[]);
+
+int mavlink_tests_main(int argc, char *argv[])
+{
+	MavlinkFtpTest* test = new MavlinkFtpTest;
+	
+	test->runTests();
+	test->printResults();
+
+	return 0;
+}
diff --git a/src/modules/mavlink/mavlink_tests/module.mk b/src/modules/mavlink/mavlink_tests/module.mk
new file mode 100644
index 000000000..07cfce1dc
--- /dev/null
+++ b/src/modules/mavlink/mavlink_tests/module.mk
@@ -0,0 +1,48 @@
+############################################################################
+#
+#   Copyright (c) 2014 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.
+#
+############################################################################
+
+#
+# System state machine tests.
+#
+
+MODULE_COMMAND		= mavlink_tests
+SRCS			= mavlink_tests.cpp \
+			mavlink_ftp_test.cpp \
+			../mavlink_ftp.cpp \
+			../mavlink.c
+
+INCLUDE_DIRS	 += $(MAVLINK_SRC)/include/mavlink
+
+MODULE_STACKSIZE = 5000
+
+EXTRACXXFLAGS	= -Weffc++ -DMAVLINK_FTP_UNIT_TEST
diff --git a/src/modules/navigator/geofence.cpp b/src/modules/navigator/geofence.cpp
index 266215308..49aec21e0 100644
--- a/src/modules/navigator/geofence.cpp
+++ b/src/modules/navigator/geofence.cpp
@@ -76,11 +76,7 @@ Geofence::~Geofence()
 
 bool Geofence::inside(const struct vehicle_global_position_s *vehicle)
 {
-	double lat = vehicle->lat / 1e7d;
-	double lon = vehicle->lon / 1e7d;
-	//float	alt = vehicle->alt;
-
-	return inside(lat, lon, vehicle->alt);
+	return inside(vehicle->lat, vehicle->lon, vehicle->alt);
 }
 
 bool Geofence::inside(double lat, double lon, float altitude)
diff --git a/src/modules/navigator/mission.cpp b/src/modules/navigator/mission.cpp
index c0e37a3ed..b33b2049f 100644
--- a/src/modules/navigator/mission.cpp
+++ b/src/modules/navigator/mission.cpp
@@ -36,12 +36,14 @@
  * Helper class to access missions
  *
  * @author Julian Oes <julian@oes.ch>
+ * @author Thomas Gubler <thomasgubler@gmail.com>
  */
 
 #include <sys/types.h>
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <float.h>
 
 #include <drivers/drv_hrt.h>
 
@@ -49,6 +51,7 @@
 #include <mavlink/mavlink_log.h>
 #include <systemlib/err.h>
 #include <geo/geo.h>
+#include <lib/mathlib/mathlib.h>
 
 #include <uORB/uORB.h>
 #include <uORB/topics/mission.h>
@@ -62,6 +65,7 @@ Mission::Mission(Navigator *navigator, const char *name) :
 	_param_onboard_enabled(this, "ONBOARD_EN"),
 	_param_takeoff_alt(this, "TAKEOFF_ALT"),
 	_param_dist_1wp(this, "DIST_1WP"),
+	_param_altmode(this, "ALTMODE"),
 	_onboard_mission({0}),
 	_offboard_mission({0}),
 	_current_onboard_mission_index(-1),
@@ -72,7 +76,11 @@ Mission::Mission(Navigator *navigator, const char *name) :
 	_mission_result({0}),
 	_mission_type(MISSION_TYPE_NONE),
 	_inited(false),
-	_dist_1wp_ok(false)
+	_dist_1wp_ok(false),
+	_missionFeasiblityChecker(),
+	_min_current_sp_distance_xy(FLT_MAX),
+	_mission_item_previous_alt(NAN),
+	_distance_current_previous(0.0f)
 {
 	/* load initial params */
 	updateParams();
@@ -144,6 +152,8 @@ Mission::on_active()
 		advance_mission();
 		set_mission_items();
 
+	} else if (_mission_type != MISSION_TYPE_NONE &&_param_altmode.get() == MISSION_ALTMODE_FOH) {
+		altitude_sp_foh_update();
 	} else {
 		/* if waypoint position reached allow loiter on the setpoint */
 		if (_waypoint_position_reached && _mission_item.nav_cmd != NAV_CMD_IDLE) {
@@ -202,7 +212,7 @@ Mission::update_offboard_mission()
 		 * however warnings are issued to the gcs via mavlink from inside the MissionFeasiblityChecker */
 		dm_item_t dm_current = DM_KEY_WAYPOINTS_OFFBOARD(_offboard_mission.dataman_id);
 
-		missionFeasiblityChecker.checkMissionFeasible(_navigator->get_vstatus()->is_rotary_wing,
+		_missionFeasiblityChecker.checkMissionFeasible(_navigator->get_vstatus()->is_rotary_wing,
 				dm_current, (size_t) _offboard_mission.count, _navigator->get_geofence(),
 				_navigator->get_home_position()->alt);
 
@@ -313,11 +323,19 @@ Mission::set_mission_items()
 	/* make sure param is up to date */
 	updateParams();
 
+	/* reset the altitude foh logic, if altitude foh is enabled (param) a new foh element starts now */
+	altitude_sp_foh_reset();
+
 	struct position_setpoint_triplet_s *pos_sp_triplet = _navigator->get_position_setpoint_triplet();
 
 	/* set previous position setpoint to current */
 	set_previous_pos_setpoint();
 
+	/* Copy previous mission item altitude (can be extended to a copy of the full mission item if needed) */
+	if (pos_sp_triplet->previous.valid) {
+		_mission_item_previous_alt = _mission_item.altitude;
+	}
+
 	/* get home distance state */
 	bool home_dist_ok = check_dist_1wp();
 	/* the home dist check provides user feedback, so we initialize it to this */
@@ -446,9 +464,75 @@ Mission::set_mission_items()
 		}
 	}
 
+	/* Save the distance between the current sp and the previous one */
+	if (pos_sp_triplet->current.valid && pos_sp_triplet->previous.valid) {
+		_distance_current_previous = get_distance_to_next_waypoint(pos_sp_triplet->current.lat,
+				pos_sp_triplet->current.lon,
+				pos_sp_triplet->previous.lat,
+				pos_sp_triplet->previous.lon);
+	}
+
+	_navigator->set_position_setpoint_triplet_updated();
+}
+
+void
+Mission::altitude_sp_foh_update()
+{
+	struct position_setpoint_triplet_s *pos_sp_triplet = _navigator->get_position_setpoint_triplet();
+
+	/* Don't change setpoint if last and current waypoint are not valid */
+	if (!pos_sp_triplet->previous.valid || !pos_sp_triplet->current.valid ||
+			!isfinite(_mission_item_previous_alt)) {
+		return;
+	}
+
+	/* Do not try to find a solution if the last waypoint is inside the acceptance radius of the current one */
+	if (_distance_current_previous - _mission_item.acceptance_radius < 0.0f) {
+		return;
+	}
+
+	/* Don't do FOH for landing and takeoff waypoints, the ground may be near
+	 * and the FW controller has a custom landing logic */
+	if (_mission_item.nav_cmd == NAV_CMD_LAND || _mission_item.nav_cmd == NAV_CMD_TAKEOFF) {
+		return;
+	}
+
+
+	/* Calculate distance to current waypoint */
+	float d_current = get_distance_to_next_waypoint(_mission_item.lat, _mission_item.lon,
+			_navigator->get_global_position()->lat, _navigator->get_global_position()->lon);
+
+	/* Save distance to waypoint if it is the smallest ever achieved, however make sure that
+	 * _min_current_sp_distance_xy is never larger than the distance between the current and the previous wp */
+	_min_current_sp_distance_xy = math::min(math::min(d_current, _min_current_sp_distance_xy),
+			_distance_current_previous);
+
+	/* if the minimal distance is smaller then the acceptance radius, we should be at waypoint alt
+	 * navigator will soon switch to the next waypoint item (if there is one) as soon as we reach this altitude */
+	if (_min_current_sp_distance_xy < _mission_item.acceptance_radius) {
+		pos_sp_triplet->current.alt = _mission_item.altitude;
+	} else {
+		/* update the altitude sp of the 'current' item in the sp triplet, but do not update the altitude sp
+		* of the mission item as it is used to check if the mission item is reached
+		* The setpoint is set linearly and such that the system reaches the current altitude at the acceptance
+		* radius around the current waypoint
+		**/
+		float delta_alt = (_mission_item.altitude - _mission_item_previous_alt);
+		float grad = -delta_alt/(_distance_current_previous - _mission_item.acceptance_radius);
+		float a = _mission_item_previous_alt - grad * _distance_current_previous;
+		pos_sp_triplet->current.alt = a + grad * _min_current_sp_distance_xy;
+
+	}
+
 	_navigator->set_position_setpoint_triplet_updated();
 }
 
+void
+Mission::altitude_sp_foh_reset()
+{
+	_min_current_sp_distance_xy = FLT_MAX;
+}
+
 bool
 Mission::read_mission_item(bool onboard, bool is_current, struct mission_item_s *mission_item)
 {
diff --git a/src/modules/navigator/mission.h b/src/modules/navigator/mission.h
index 4da6a1155..a91c89968 100644
--- a/src/modules/navigator/mission.h
+++ b/src/modules/navigator/mission.h
@@ -36,6 +36,7 @@
  * Navigator mode to access missions
  *
  * @author Julian Oes <julian@oes.ch>
+ * @author Thomas Gubler <thomasgubler@gmail.com>
  */
 
 #ifndef NAVIGATOR_MISSION_H
@@ -75,6 +76,11 @@ public:
 
 	virtual void on_active();
 
+	enum mission_altitude_mode {
+		MISSION_ALTMODE_ZOH = 0,
+		MISSION_ALTMODE_FOH = 1
+	};
+
 private:
 	/**
 	 * Update onboard mission topic
@@ -103,6 +109,16 @@ private:
 	void set_mission_items();
 
 	/**
+	 * Updates the altitude sp to follow a foh
+	 */
+	void altitude_sp_foh_update();
+
+	/**
+	 * Resets the altitude sp foh logic
+	 */
+	void altitude_sp_foh_reset();
+
+	/**
 	 * Read current or next mission item from the dataman and watch out for DO_JUMPS
 	 * @return true if successful
 	 */
@@ -136,6 +152,7 @@ private:
 	control::BlockParamInt _param_onboard_enabled;
 	control::BlockParamFloat _param_takeoff_alt;
 	control::BlockParamFloat _param_dist_1wp;
+	control::BlockParamInt _param_altmode;
 
 	struct mission_s _onboard_mission;
 	struct mission_s _offboard_mission;
@@ -157,7 +174,13 @@ private:
 	bool _inited;
 	bool _dist_1wp_ok;
 
-	MissionFeasibilityChecker missionFeasiblityChecker; /**< class that checks if a mission is feasible */
+	MissionFeasibilityChecker _missionFeasiblityChecker; /**< class that checks if a mission is feasible */
+
+	float _min_current_sp_distance_xy; /**< minimum distance which was achieved to the current waypoint  */
+	float _mission_item_previous_alt; /**< holds the altitude of the previous mission item,
+					    can be replaced by a full copy of the previous mission item if needed*/
+	float _distance_current_previous; /**< distance from previous to current sp in pos_sp_triplet,
+					    only use if current and previous are valid */
 };
 
 #endif
diff --git a/src/modules/navigator/mission_block.cpp b/src/modules/navigator/mission_block.cpp
index 4adf77dce..723caec7c 100644
--- a/src/modules/navigator/mission_block.cpp
+++ b/src/modules/navigator/mission_block.cpp
@@ -113,6 +113,19 @@ MissionBlock::is_mission_item_reached()
 			if (dist >= 0.0f && dist <= _navigator->get_acceptance_radius()) {
 				_waypoint_position_reached = true;
 			}
+		} else if (!_navigator->get_vstatus()->is_rotary_wing &&
+			(_mission_item.nav_cmd == NAV_CMD_LOITER_UNLIMITED ||
+			_mission_item.nav_cmd == NAV_CMD_LOITER_TIME_LIMIT ||
+			_mission_item.nav_cmd == NAV_CMD_LOITER_TURN_COUNT)) {
+			/* Loiter mission item on a non rotary wing: the aircraft is going to circle the
+			 * coordinates with a radius equal to the loiter_radius field. It is not flying
+			 * through the waypoint center.
+			 * Therefore the item is marked as reached once the system reaches the loiter
+			 * radius (+ some margin). Time inside and turn count is handled elsewhere.
+			 */
+			if (dist >= 0.0f && dist <= _mission_item.loiter_radius * 1.2f) {
+				_waypoint_position_reached = true;
+			}
 		} else {
 			/* for normal mission items used their acceptance radius */
 			if (dist >= 0.0f && dist <= _mission_item.acceptance_radius) {
diff --git a/src/modules/navigator/mission_feasibility_checker.cpp b/src/modules/navigator/mission_feasibility_checker.cpp
index 606521f20..7ae7f60cb 100644
--- a/src/modules/navigator/mission_feasibility_checker.cpp
+++ b/src/modules/navigator/mission_feasibility_checker.cpp
@@ -84,7 +84,12 @@ bool MissionFeasibilityChecker::checkMissionFeasible(bool isRotarywing, dm_item_
 bool MissionFeasibilityChecker::checkMissionFeasibleRotarywing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt)
 {
 
-	return  (checkGeofence(dm_current, nMissionItems, geofence) && checkHomePositionAltitude(dm_current, nMissionItems, home_alt));
+	/* Perform checks and issue feedback to the user for all checks */
+	bool resGeofence = checkGeofence(dm_current, nMissionItems, geofence);
+	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt);
+
+	/* Mission is only marked as feasible if all checks return true */
+	return (resGeofence && resHomeAltitude);
 }
 
 bool MissionFeasibilityChecker::checkMissionFeasibleFixedwing(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence, float home_alt)
@@ -93,7 +98,13 @@ bool MissionFeasibilityChecker::checkMissionFeasibleFixedwing(dm_item_t dm_curre
 	updateNavigationCapabilities();
 //	warnx("_nav_caps.landing_slope_angle_rad %.4f, _nav_caps.landing_horizontal_slope_displacement %.4f", _nav_caps.landing_slope_angle_rad, _nav_caps.landing_horizontal_slope_displacement);
 
-	return (checkFixedWingLanding(dm_current, nMissionItems) && checkGeofence(dm_current, nMissionItems, geofence) && checkHomePositionAltitude(dm_current, nMissionItems, home_alt));
+	/* Perform checks and issue feedback to the user for all checks */
+	bool resLanding = checkFixedWingLanding(dm_current, nMissionItems);
+	bool resGeofence = checkGeofence(dm_current, nMissionItems, geofence);
+	bool resHomeAltitude = checkHomePositionAltitude(dm_current, nMissionItems, home_alt);
+
+	/* Mission is only marked as feasible if all checks return true */
+	return (resLanding && resGeofence && resHomeAltitude);
 }
 
 bool MissionFeasibilityChecker::checkGeofence(dm_item_t dm_current, size_t nMissionItems, Geofence &geofence)
@@ -216,9 +227,8 @@ bool MissionFeasibilityChecker::checkFixedWingLanding(dm_item_t dm_current, size
 		}
 	}
 
-
-//	float slope_alt = wp_altitude + _H0 * expf(-math::max(0.0f, _flare_length - wp_distance)/_flare_constant) - _H1_virt;
-	return false;
+	/* No landing waypoints or no waypoints */
+	return true;
 }
 
 void MissionFeasibilityChecker::updateNavigationCapabilities()
diff --git a/src/modules/navigator/mission_params.c b/src/modules/navigator/mission_params.c
index d15e1e771..04c01fe51 100644
--- a/src/modules/navigator/mission_params.c
+++ b/src/modules/navigator/mission_params.c
@@ -82,3 +82,16 @@ PARAM_DEFINE_INT32(MIS_ONBOARD_EN, 1);
  * @group Mission
  */
 PARAM_DEFINE_FLOAT(MIS_DIST_1WP, 500);
+
+/**
+ * Altitude setpoint mode
+ *
+ * 0: the system will follow a zero order hold altitude setpoint
+ * 1: the system will follow a first order hold altitude setpoint
+ * values follow the definition in enum mission_altitude_mode
+ *
+ * @min 0
+ * @max 1
+ * @group Mission
+ */
+PARAM_DEFINE_INT32(MIS_ALTMODE, 0);
diff --git a/src/modules/systemlib/param/param.c b/src/modules/systemlib/param/param.c
index e44e6cdb0..6b8d0e634 100644
--- a/src/modules/systemlib/param/param.c
+++ b/src/modules/systemlib/param/param.c
@@ -322,7 +322,8 @@ param_get_value_ptr(param_t param)
 			v = &param_info_base[param].val;
 		}
 
-		if (param_type(param) == PARAM_TYPE_STRUCT) {
+		if (param_type(param) >= PARAM_TYPE_STRUCT
+				&& param_type(param) <= PARAM_TYPE_STRUCT_MAX) {
 			result = v->p;
 
 		} else {
diff --git a/src/modules/systemlib/param/param.h b/src/modules/systemlib/param/param.h
index 084cd931a..dc73b37e9 100644
--- a/src/modules/systemlib/param/param.h
+++ b/src/modules/systemlib/param/param.h
@@ -307,7 +307,7 @@ __EXPORT int 		param_load_default(void);
 	struct param_info_s __param__##_name = {	\
 		#_name,					\
 		PARAM_TYPE_STRUCT + sizeof(_default),	\
-		.val.p = &_default;			\
+		.val.p = &_default			\
 	}
 
 /**
diff --git a/src/modules/uavcan/sensors/gnss.cpp b/src/modules/uavcan/sensors/gnss.cpp
index 0d67aad47..24afe6aaf 100644
--- a/src/modules/uavcan/sensors/gnss.cpp
+++ b/src/modules/uavcan/sensors/gnss.cpp
@@ -43,8 +43,6 @@
 #include <systemlib/err.h>
 #include <mathlib/mathlib.h>
 
-#define MM_PER_CM 			10	// Millimeters per centimeter
-
 const char *const UavcanGnssBridge::NAME = "gnss";
 
 UavcanGnssBridge::UavcanGnssBridge(uavcan::INode &node) :
@@ -95,9 +93,9 @@ void UavcanGnssBridge::gnss_fix_sub_cb(const uavcan::ReceivedDataStructure<uavca
 	auto report = ::vehicle_gps_position_s();
 
 	report.timestamp_position = hrt_absolute_time();
-	report.lat = msg.lat_1e7;
-	report.lon = msg.lon_1e7;
-	report.alt = msg.alt_1e2 * MM_PER_CM;	// Convert from centimeter (1e2) to millimeters (1e3)
+	report.lat = msg.latitude_deg_1e8 / 10;
+	report.lon = msg.longitude_deg_1e8 / 10;
+	report.alt = msg.height_msl_mm;
 
 	report.timestamp_variance = report.timestamp_position;
 
diff --git a/src/modules/unit_test/unit_test.cpp b/src/modules/unit_test/unit_test.cpp
index 02d1af481..be3b9461a 100644
--- a/src/modules/unit_test/unit_test.cpp
+++ b/src/modules/unit_test/unit_test.cpp
@@ -56,3 +56,8 @@ void UnitTest::printAssert(const char* msg, const char* test, const char* file,
 {
     warnx("Assertion failed: %s - %s (%s:%d)", msg, test, file, line);
 }
+
+void UnitTest::printCompare(const char* msg, const char *v1_text, int v1, const char *v2_text, int v2, const char* file, int line)
+{
+	warnx("Compare failed: %s - (%s:%d) (%s:%d) (%s:%d)", msg, v1_text, v1, v2_text, v2, file, line);
+}
diff --git a/src/modules/unit_test/unit_test.h b/src/modules/unit_test/unit_test.h
index 32eb8c308..1a5489709 100644
--- a/src/modules/unit_test/unit_test.h
+++ b/src/modules/unit_test/unit_test.h
@@ -52,11 +52,15 @@ INLINE_GLOBAL(const char*, mu_last_test)
 
 	UnitTest();
     virtual ~UnitTest();
+	
+	virtual void init(void) { };
+	virtual void cleanup(void) { };
 
     virtual void runTests(void) = 0;
     void printResults(void);
     
     void printAssert(const char* msg, const char* test, const char* file, int line);
+	void printCompare(const char* msg, const char *v1_text, int v1, const char *v2_text, int v2, const char* file, int line);
     
 #define ut_assert(message, test)                                \
     do {                                                        \
@@ -68,10 +72,23 @@ INLINE_GLOBAL(const char*, mu_last_test)
         }                                                       \
     } while (0)
     
+#define ut_compare(message, v1, v2)							\
+	do {										\
+		int _v1 = v1;								\
+		int _v2 = v2;								\
+		if (_v1 != _v2) {							\
+			printCompare(message, #v1, _v1, #v2, _v2, __FILE__, __LINE__);	\
+			return false;							\
+		} else {								\
+			mu_assertion()++;						\
+		}									\
+	} while (0)
+    
 #define ut_run_test(test)                       \
     do {                                        \
         warnx("RUNNING TEST: %s", #test);       \
         mu_tests_run()++;                       \
+	init();					\
         if (!test()) {                          \
             warnx("TEST FAILED: %s", #test);    \
             mu_tests_failed()++;                \
@@ -79,6 +96,7 @@ INLINE_GLOBAL(const char*, mu_last_test)
             warnx("TEST PASSED: %s", #test);    \
             mu_tests_passed()++;                \
         }                                       \
+	cleanup();				\
     } while (0)
 
 };