Merged with master, cleanup of varlength prototypemavlink_variable_length

8 files changed, 628 insertions, 624 deletions

diff --git a/src/drivers/gps/gps.cpp b/src/drivers/gps/gps.cpp
index 38835418b..a736cbdf6 100644
--- a/src/drivers/gps/gps.cpp
+++ b/src/drivers/gps/gps.cpp
@@ -85,7 +85,7 @@ static const int ERROR = -1;
 class GPS : public device::CDev
 {
 public:
-	GPS(const char* uart_path);
+	GPS(const char *uart_path, bool fake_gps);
 	virtual ~GPS();
 
 	virtual int			init();
@@ -112,6 +112,7 @@ private:
 	struct vehicle_gps_position_s 	_report;					///< uORB topic for gps position
 	orb_advert_t			_report_pub;					///< uORB pub for gps position
 	float				_rate;						///< position update rate
+	bool				_fake_gps;					///< fake gps output
 
 
 	/**
@@ -156,7 +157,7 @@ GPS	*g_dev;
 }
 
 
-GPS::GPS(const char* uart_path) :
+GPS::GPS(const char *uart_path, bool fake_gps) :
 	CDev("gps", GPS_DEVICE_PATH),
 	_task_should_exit(false),
 	_healthy(false),
@@ -164,7 +165,8 @@ GPS::GPS(const char* uart_path) :
 	_mode(GPS_DRIVER_MODE_UBX),
 	_Helper(nullptr),
 	_report_pub(-1),
-	_rate(0.0f)
+	_rate(0.0f),
+	_fake_gps(fake_gps)
 {
 	/* store port name */
 	strncpy(_port, uart_path, sizeof(_port));
@@ -192,6 +194,7 @@ GPS::~GPS()
 	/* well, kill it anyway, though this will probably crash */
 	if (_task != -1)
 		task_delete(_task);
+
 	g_dev = nullptr;
 
 }
@@ -263,84 +266,143 @@ GPS::task_main()
 	/* loop handling received serial bytes and also configuring in between */
 	while (!_task_should_exit) {
 
-		if (_Helper != nullptr) {
-			delete(_Helper);
-			/* set to zero to ensure parser is not used while not instantiated */
-			_Helper = nullptr;
-		}
+		if (_fake_gps) {
+
+			_report.timestamp_position = hrt_absolute_time();
+			_report.lat = (int32_t)47.378301e7f;
+			_report.lon = (int32_t)8.538777e7f;
+			_report.alt = (int32_t)400e3f;
+			_report.timestamp_variance = hrt_absolute_time();
+			_report.s_variance_m_s = 10.0f;
+			_report.p_variance_m = 10.0f;
+			_report.c_variance_rad = 0.1f;
+			_report.fix_type = 3;
+			_report.eph_m = 10.0f;
+			_report.epv_m = 10.0f;
+			_report.timestamp_velocity = hrt_absolute_time();
+			_report.vel_n_m_s = 0.0f;
+			_report.vel_e_m_s = 0.0f;
+			_report.vel_d_m_s = 0.0f;
+			_report.vel_m_s = sqrtf(_report.vel_n_m_s * _report.vel_n_m_s + _report.vel_e_m_s * _report.vel_e_m_s + _report.vel_d_m_s * _report.vel_d_m_s);
+			_report.cog_rad = 0.0f;
+			_report.vel_ned_valid = true;
+
+			//no time and satellite information simulated
+
+			if (!(_pub_blocked)) {
+				if (_report_pub > 0) {
+					orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
+
+				} else {
+					_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
+				}
+			}
+
+			usleep(2e5);
+
+		} else {
+
+			if (_Helper != nullptr) {
+				delete(_Helper);
+				/* set to zero to ensure parser is not used while not instantiated */
+				_Helper = nullptr;
+			}
 
-		switch (_mode) {
+			switch (_mode) {
 			case GPS_DRIVER_MODE_UBX:
 				_Helper = new UBX(_serial_fd, &_report);
 				break;
+
 			case GPS_DRIVER_MODE_MTK:
 				_Helper = new MTK(_serial_fd, &_report);
 				break;
-			case GPS_DRIVER_MODE_NMEA:
-				//_Helper = new NMEA(); //TODO: add NMEA
-				break;
+
 			default:
 				break;
-		}
-		unlock();
-		if (_Helper->configure(_baudrate) == 0) {
+			}
+
 			unlock();
 
-			// GPS is obviously detected successfully, reset statistics
-			_Helper->reset_update_rates();
+			if (_Helper->configure(_baudrate) == 0) {
+				unlock();
 
-			while (_Helper->receive(TIMEOUT_5HZ) > 0 && !_task_should_exit) {
-//				lock();
-				/* opportunistic publishing - else invalid data would end up on the bus */
-				if (_report_pub > 0) {
-					orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
-				} else {
-					_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
-				}
+				// GPS is obviously detected successfully, reset statistics
+				_Helper->reset_update_rates();
+
+				while (_Helper->receive(TIMEOUT_5HZ) > 0 && !_task_should_exit) {
+	//				lock();
+					/* opportunistic publishing - else invalid data would end up on the bus */
+
+					if (!(_pub_blocked)) {
+						if (_report_pub > 0) {
+							orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
 
-				last_rate_count++;
+						} else {
+							_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
+						}
+					}
 
-				/* measure update rate every 5 seconds */
-				if (hrt_absolute_time() - last_rate_measurement > RATE_MEASUREMENT_PERIOD) {
-					_rate = last_rate_count / ((float)((hrt_absolute_time() - last_rate_measurement)) / 1000000.0f);
-					last_rate_measurement = hrt_absolute_time();
-					last_rate_count = 0;
-					_Helper->store_update_rates();
-					_Helper->reset_update_rates();
+					last_rate_count++;
+
+					/* measure update rate every 5 seconds */
+					if (hrt_absolute_time() - last_rate_measurement > RATE_MEASUREMENT_PERIOD) {
+						_rate = last_rate_count / ((float)((hrt_absolute_time() - last_rate_measurement)) / 1000000.0f);
+						last_rate_measurement = hrt_absolute_time();
+						last_rate_count = 0;
+						_Helper->store_update_rates();
+						_Helper->reset_update_rates();
+					}
+
+					if (!_healthy) {
+						char *mode_str = "unknown";
+
+						switch (_mode) {
+						case GPS_DRIVER_MODE_UBX:
+							mode_str = "UBX";
+							break;
+
+						case GPS_DRIVER_MODE_MTK:
+							mode_str = "MTK";
+							break;
+
+						default:
+							break;
+						}
+
+						warnx("module found: %s", mode_str);
+						_healthy = true;
+					}
 				}
 
-				if (!_healthy) {
-					warnx("module found");
-					_healthy = true;
+				if (_healthy) {
+					warnx("module lost");
+					_healthy = false;
+					_rate = 0.0f;
 				}
-			}
-			if (_healthy) {
-				warnx("module lost");
-				_healthy = false;
-				_rate = 0.0f;
+
+				lock();
 			}
 
 			lock();
-		}
-		lock();
 
-		/* select next mode */
-		switch (_mode) {
+			/* select next mode */
+			switch (_mode) {
 			case GPS_DRIVER_MODE_UBX:
 				_mode = GPS_DRIVER_MODE_MTK;
 				break;
+
 			case GPS_DRIVER_MODE_MTK:
 				_mode = GPS_DRIVER_MODE_UBX;
 				break;
-		//				case GPS_DRIVER_MODE_NMEA:
-		//					_mode = GPS_DRIVER_MODE_UBX;
-		//					break;
+
 			default:
 				break;
+			}
 		}
 
 	}
-	debug("exiting");
+
+	warnx("exiting");
 
 	::close(_serial_fd);
 
@@ -361,23 +423,25 @@ void
 GPS::print_info()
 {
 	switch (_mode) {
-		case GPS_DRIVER_MODE_UBX:
-			warnx("protocol: UBX");
-			break;
-		case GPS_DRIVER_MODE_MTK:
-			warnx("protocol: MTK");
-			break;
-		case GPS_DRIVER_MODE_NMEA:
-			warnx("protocol: NMEA");
-			break;
-		default:
-			break;
+	case GPS_DRIVER_MODE_UBX:
+		warnx("protocol: UBX");
+		break;
+
+	case GPS_DRIVER_MODE_MTK:
+		warnx("protocol: MTK");
+		break;
+
+	default:
+		break;
 	}
+
 	warnx("port: %s, baudrate: %d, status: %s", _port, _baudrate, (_healthy) ? "OK" : "NOT OK");
+
 	if (_report.timestamp_position != 0) {
-		warnx("position lock: %dD, last update %4.2f seconds ago", (int)_report.fix_type,
-			(double)((float)(hrt_absolute_time() - _report.timestamp_position) / 1000000.0f));
+		warnx("position lock: %dD, satellites: %d, last update: %fms ago", (int)_report.fix_type,
+				_report.satellites_visible, (hrt_absolute_time() - _report.timestamp_position) / 1000.0f);
 		warnx("lat: %d, lon: %d, alt: %d", _report.lat, _report.lon, _report.alt);
+		warnx("eph: %.2fm, epv: %.2fm", _report.eph_m, _report.epv_m);
 		warnx("rate position: \t%6.2f Hz", (double)_Helper->get_position_update_rate());
 		warnx("rate velocity: \t%6.2f Hz", (double)_Helper->get_velocity_update_rate());
 		warnx("rate publication:\t%6.2f Hz", (double)_rate);
@@ -395,7 +459,7 @@ namespace gps
 
 GPS	*g_dev;
 
-void	start(const char *uart_path);
+void	start(const char *uart_path, bool fake_gps);
 void	stop();
 void	test();
 void	reset();
@@ -405,7 +469,7 @@ void	info();
  * Start the driver.
  */
 void
-start(const char *uart_path)
+start(const char *uart_path, bool fake_gps)
 {
 	int fd;
 
@@ -413,7 +477,7 @@ start(const char *uart_path)
 		errx(1, "already started");
 
 	/* create the driver */
-	g_dev = new GPS(uart_path);
+	g_dev = new GPS(uart_path, fake_gps);
 
 	if (g_dev == nullptr)
 		goto fail;
@@ -428,6 +492,7 @@ start(const char *uart_path)
 		errx(1, "Could not open device path: %s\n", GPS_DEVICE_PATH);
 		goto fail;
 	}
+
 	exit(0);
 
 fail:
@@ -503,7 +568,8 @@ gps_main(int argc, char *argv[])
 {
 
 	/* set to default */
-	char* device_name = GPS_DEFAULT_UART_PORT;
+	char *device_name = GPS_DEFAULT_UART_PORT;
+	bool fake_gps = false;
 
 	/*
 	 * Start/load the driver.
@@ -513,15 +579,24 @@ gps_main(int argc, char *argv[])
 		if (argc > 3) {
 			if (!strcmp(argv[2], "-d")) {
 				device_name = argv[3];
+
 			} else {
 				goto out;
 			}
 		}
-		gps::start(device_name);
+
+		/* Detect fake gps option */
+		for (int i = 2; i < argc; i++) {
+			if (!strcmp(argv[i], "-f"))
+				fake_gps = true;
+		}
+
+		gps::start(device_name, fake_gps);
 	}
 
 	if (!strcmp(argv[1], "stop"))
 		gps::stop();
+
 	/*
 	 * Test the driver/device.
 	 */
@@ -541,5 +616,5 @@ gps_main(int argc, char *argv[])
 		gps::info();
 
 out:
-	errx(1, "unrecognized command, try 'start', 'stop', 'test', 'reset' or 'status' [-d /dev/ttyS0-n]");
+	errx(1, "unrecognized command, try 'start', 'stop', 'test', 'reset' or 'status' [-d /dev/ttyS0-n][-f]");
 }
diff --git a/src/drivers/gps/gps_helper.cpp b/src/drivers/gps/gps_helper.cpp
index ba86d370a..2360ff39b 100644
--- a/src/drivers/gps/gps_helper.cpp
+++ b/src/drivers/gps/gps_helper.cpp
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2012,2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012-2014 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
@@ -41,6 +39,9 @@
 
 /**
  * @file gps_helper.cpp
+ *
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
  */
 
 float
@@ -87,13 +88,15 @@ GPS_Helper::set_baudrate(const int &fd, unsigned baud)
 
 	case 115200: speed = B115200; break;
 
-	warnx("try baudrate: %d\n", speed);
+		warnx("try baudrate: %d\n", speed);
 
 	default:
 		warnx("ERROR: Unsupported baudrate: %d\n", baud);
 		return -EINVAL;
 	}
+
 	struct termios uart_config;
+
 	int termios_state;
 
 	/* fill the struct for the new configuration */
@@ -109,14 +112,17 @@ GPS_Helper::set_baudrate(const int &fd, unsigned baud)
 		warnx("ERROR setting config: %d (cfsetispeed)\n", termios_state);
 		return -1;
 	}
+
 	if ((termios_state = cfsetospeed(&uart_config, speed)) < 0) {
 		warnx("ERROR setting config: %d (cfsetospeed)\n", termios_state);
 		return -1;
 	}
+
 	if ((termios_state = tcsetattr(fd, TCSANOW, &uart_config)) < 0) {
 		warnx("ERROR setting baudrate (tcsetattr)\n");
 		return -1;
 	}
+
 	/* XXX if resetting the parser here, ensure it does exist (check for null pointer) */
 	return 0;
 }
diff --git a/src/drivers/gps/gps_helper.h b/src/drivers/gps/gps_helper.h
index defc1a074..cfb9e0d43 100644
--- a/src/drivers/gps/gps_helper.h
+++ b/src/drivers/gps/gps_helper.h
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012-2014 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
@@ -33,8 +31,10 @@
  *
  ****************************************************************************/
 
-/** 
+/**
  * @file gps_helper.h
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
  */
 
 #ifndef GPS_HELPER_H
diff --git a/src/drivers/gps/module.mk b/src/drivers/gps/module.mk
index 097db2abf..82c67d40a 100644
--- a/src/drivers/gps/module.mk
+++ b/src/drivers/gps/module.mk
@@ -1,6 +1,6 @@
 ############################################################################
 #
-#   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
+#   Copyright (c) 2012-2014 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
diff --git a/src/drivers/gps/mtk.cpp b/src/drivers/gps/mtk.cpp
index 62941d74b..c90ecbe28 100644
--- a/src/drivers/gps/mtk.cpp
+++ b/src/drivers/gps/mtk.cpp
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,7 +31,12 @@
  *
  ****************************************************************************/
 
-/* @file mkt.cpp */
+/**
+ * @file mtk.cpp
+ *
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
+ */
 
 #include <unistd.h>
 #include <stdio.h>
@@ -48,9 +51,9 @@
 
 
 MTK::MTK(const int &fd, struct vehicle_gps_position_s *gps_position) :
-_fd(fd),
-_gps_position(gps_position),
-_mtk_revision(0)
+	_fd(fd),
+	_gps_position(gps_position),
+	_mtk_revision(0)
 {
 	decode_init();
 }
@@ -73,24 +76,28 @@ MTK::configure(unsigned &baudrate)
 		warnx("mtk: config write failed");
 		return -1;
 	}
+
 	usleep(10000);
 
 	if (strlen(MTK_SET_BINARY) != write(_fd, MTK_SET_BINARY, strlen(MTK_SET_BINARY))) {
 		warnx("mtk: config write failed");
 		return -1;
 	}
+
 	usleep(10000);
 
 	if (strlen(SBAS_ON) != write(_fd, SBAS_ON, strlen(SBAS_ON))) {
 		warnx("mtk: config write failed");
 		return -1;
 	}
+
 	usleep(10000);
 
 	if (strlen(WAAS_ON) != write(_fd, WAAS_ON, strlen(WAAS_ON))) {
 		warnx("mtk: config write failed");
 		return -1;
 	}
+
 	usleep(10000);
 
 	if (strlen(MTK_NAVTHRES_OFF) != write(_fd, MTK_NAVTHRES_OFF, strlen(MTK_NAVTHRES_OFF))) {
@@ -128,12 +135,15 @@ MTK::receive(unsigned timeout)
 					handle_message(packet);
 					return 1;
 				}
+
 				/* in case we keep trying but only get crap from GPS */
-				if (time_started + timeout*1000 < hrt_absolute_time() ) {
+				if (time_started + timeout * 1000 < hrt_absolute_time()) {
 					return -1;
 				}
+
 				j++;
 			}
+
 			/* everything is read */
 			j = count = 0;
 		}
@@ -181,6 +191,7 @@ MTK::parse_char(uint8_t b, gps_mtk_packet_t &packet)
 		if (b == MTK_SYNC1_V16) {
 			_decode_state = MTK_DECODE_GOT_CK_A;
 			_mtk_revision = 16;
+
 		} else if (b == MTK_SYNC1_V19) {
 			_decode_state = MTK_DECODE_GOT_CK_A;
 			_mtk_revision = 19;
@@ -201,7 +212,7 @@ MTK::parse_char(uint8_t b, gps_mtk_packet_t &packet)
 			add_byte_to_checksum(b);
 
 		// Fill packet buffer
-		((uint8_t*)(&packet))[_rx_count] = b;
+		((uint8_t *)(&packet))[_rx_count] = b;
 		_rx_count++;
 
 		/* Packet size minus checksum, XXX ? */
@@ -209,14 +220,17 @@ MTK::parse_char(uint8_t b, gps_mtk_packet_t &packet)
 			/* Compare checksum */
 			if (_rx_ck_a == packet.ck_a && _rx_ck_b == packet.ck_b) {
 				ret = 1;
+
 			} else {
 				warnx("MTK Checksum invalid");
 				ret = -1;
 			}
+
 			// Reset state machine to decode next packet
 			decode_init();
 		}
 	}
+
 	return ret;
 }
 
@@ -226,19 +240,22 @@ MTK::handle_message(gps_mtk_packet_t &packet)
 	if (_mtk_revision == 16) {
 		_gps_position->lat = packet.latitude * 10; // from degrees*1e6 to degrees*1e7
 		_gps_position->lon = packet.longitude * 10; // from degrees*1e6 to degrees*1e7
+
 	} else if (_mtk_revision == 19) {
 		_gps_position->lat = packet.latitude; // both degrees*1e7
 		_gps_position->lon = packet.longitude; // both degrees*1e7
+
 	} else {
 		warnx("mtk: unknown revision");
 		_gps_position->lat = 0;
 		_gps_position->lon = 0;
 	}
+
 	_gps_position->alt = (int32_t)(packet.msl_altitude * 10); // from cm to mm
 	_gps_position->fix_type = packet.fix_type;
 	_gps_position->eph_m = packet.hdop; // XXX: Check this because eph_m is in m and hdop is without unit
 	_gps_position->epv_m = 0.0; //unknown in mtk custom mode
-	_gps_position->vel_m_s = ((float)packet.ground_speed)*1e-2f; // from cm/s to m/s
+	_gps_position->vel_m_s = ((float)packet.ground_speed) * 1e-2f; // from cm/s to m/s
 	_gps_position->cog_rad = ((float)packet.heading) * M_DEG_TO_RAD_F * 1e-2f; //from deg *100 to rad
 	_gps_position->satellites_visible = packet.satellites;
 
diff --git a/src/drivers/gps/mtk.h b/src/drivers/gps/mtk.h
index b5cfbf0a6..a2d5e27bb 100644
--- a/src/drivers/gps/mtk.h
+++ b/src/drivers/gps/mtk.h
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2008-2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,7 +31,12 @@
  *
  ****************************************************************************/
 
-/* @file mtk.h */
+/**
+ * @file mtk.cpp
+ *
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
+ */
 
 #ifndef MTK_H_
 #define MTK_H_
diff --git a/src/drivers/gps/ubx.cpp b/src/drivers/gps/ubx.cpp
index b3093b0f6..8a2afecb7 100644
--- a/src/drivers/gps/ubx.cpp
+++ b/src/drivers/gps/ubx.cpp
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -39,15 +37,21 @@
  * U-Blox protocol implementation. Following u-blox 6/7 Receiver Description
  * including Prototol Specification.
  *
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
+ * @author Anton Babushkin <anton.babushkin@me.com>
+ *
  * @see http://www.u-blox.com/images/downloads/Product_Docs/u-blox6_ReceiverDescriptionProtocolSpec_%28GPS.G6-SW-10018%29.pdf
  */
 
-#include <unistd.h>
-#include <stdio.h>
-#include <poll.h>
+#include <assert.h>
 #include <math.h>
+#include <poll.h>
+#include <stdio.h>
 #include <string.h>
-#include <assert.h>
+#include <time.h>
+#include <unistd.h>
+
 #include <systemlib/err.h>
 #include <uORB/uORB.h>
 #include <uORB/topics/vehicle_gps_position.h>
@@ -55,13 +59,17 @@
 
 #include "ubx.h"
 
-#define UBX_CONFIG_TIMEOUT 100
+#define UBX_CONFIG_TIMEOUT		200		// ms, timeout for waiting ACK
+#define UBX_PACKET_TIMEOUT		2		// ms, if now data during this delay assume that full update received
+#define UBX_WAIT_BEFORE_READ	20		// ms, wait before reading to save read() calls
+#define DISABLE_MSG_INTERVAL	1000000	// us, try to disable message with this interval
 
 UBX::UBX(const int &fd, struct vehicle_gps_position_s *gps_position) :
-_fd(fd),
-_gps_position(gps_position),
-_waiting_for_ack(false),
-_disable_cmd_counter(0)
+	_fd(fd),
+	_gps_position(gps_position),
+	_configured(false),
+	_waiting_for_ack(false),
+	_disable_cmd_last(0)
 {
 	decode_init();
 }
@@ -73,12 +81,13 @@ UBX::~UBX()
 int
 UBX::configure(unsigned &baudrate)
 {
-	_waiting_for_ack = true;
-
+	_configured = false;
 	/* try different baudrates */
 	const unsigned baudrates_to_try[] = {9600, 38400, 19200, 57600, 115200};
 
-	for (int baud_i = 0; baud_i < 5; baud_i++) {
+	int baud_i;
+
+	for (baud_i = 0; baud_i < 5; baud_i++) {
 		baudrate = baudrates_to_try[baud_i];
 		set_baudrate(_fd, baudrate);
 
@@ -89,8 +98,8 @@ UBX::configure(unsigned &baudrate)
 		/* Set everything else of the packet to 0, otherwise the module wont accept it */
 		memset(&cfg_prt_packet, 0, sizeof(cfg_prt_packet));
 
-		_clsID_needed = UBX_CLASS_CFG;
-		_msgID_needed = UBX_MESSAGE_CFG_PRT;
+		_message_class_needed = UBX_CLASS_CFG;
+		_message_id_needed = UBX_MESSAGE_CFG_PRT;
 
 		/* Define the package contents, don't change the baudrate */
 		cfg_prt_packet.clsID		= UBX_CLASS_CFG;
@@ -102,9 +111,9 @@ UBX::configure(unsigned &baudrate)
 		cfg_prt_packet.inProtoMask	= UBX_CFG_PRT_PAYLOAD_INPROTOMASK;
 		cfg_prt_packet.outProtoMask	= UBX_CFG_PRT_PAYLOAD_OUTPROTOMASK;
 
-		send_config_packet(_fd, (uint8_t*)&cfg_prt_packet, sizeof(cfg_prt_packet));
+		send_config_packet(_fd, (uint8_t *)&cfg_prt_packet, sizeof(cfg_prt_packet));
 
-		if (receive(UBX_CONFIG_TIMEOUT) < 0) {
+		if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
 			/* try next baudrate */
 			continue;
 		}
@@ -120,100 +129,125 @@ UBX::configure(unsigned &baudrate)
 		cfg_prt_packet.inProtoMask	= UBX_CFG_PRT_PAYLOAD_INPROTOMASK;
 		cfg_prt_packet.outProtoMask	= UBX_CFG_PRT_PAYLOAD_OUTPROTOMASK;
 
-		send_config_packet(_fd, (uint8_t*)&cfg_prt_packet, sizeof(cfg_prt_packet));
-		
+		send_config_packet(_fd, (uint8_t *)&cfg_prt_packet, sizeof(cfg_prt_packet));
+
 		/* no ACK is expected here, but read the buffer anyway in case we actually get an ACK */
-		receive(UBX_CONFIG_TIMEOUT);
-		
+		wait_for_ack(UBX_CONFIG_TIMEOUT);
+
 		if (UBX_CFG_PRT_PAYLOAD_BAUDRATE != baudrate) {
 			set_baudrate(_fd, UBX_CFG_PRT_PAYLOAD_BAUDRATE);
 			baudrate = UBX_CFG_PRT_PAYLOAD_BAUDRATE;
 		}
 
-		/* send a CFT-RATE message to define update rate */
-		type_gps_bin_cfg_rate_packet_t cfg_rate_packet;
-		memset(&cfg_rate_packet, 0, sizeof(cfg_rate_packet));
+		/* at this point we have correct baudrate on both ends */
+		break;
+	}
 
-		_clsID_needed = UBX_CLASS_CFG;
-		_msgID_needed = UBX_MESSAGE_CFG_RATE;
+	if (baud_i >= 5) {
+		return 1;
+	}
 
-		cfg_rate_packet.clsID		= UBX_CLASS_CFG;
-		cfg_rate_packet.msgID		= UBX_MESSAGE_CFG_RATE;
-		cfg_rate_packet.length		= UBX_CFG_RATE_LENGTH;
-		cfg_rate_packet.measRate	= UBX_CFG_RATE_PAYLOAD_MEASINTERVAL;
-		cfg_rate_packet.navRate		= UBX_CFG_RATE_PAYLOAD_NAVRATE;
-		cfg_rate_packet.timeRef		= UBX_CFG_RATE_PAYLOAD_TIMEREF;
+	/* send a CFG-RATE message to define update rate */
+	type_gps_bin_cfg_rate_packet_t cfg_rate_packet;
+	memset(&cfg_rate_packet, 0, sizeof(cfg_rate_packet));
 
-		send_config_packet(_fd, (uint8_t*)&cfg_rate_packet, sizeof(cfg_rate_packet));
-		if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
-			/* try next baudrate */
-			continue;
-		}
+	_message_class_needed = UBX_CLASS_CFG;
+	_message_id_needed = UBX_MESSAGE_CFG_RATE;
 
-		/* send a NAV5 message to set the options for the internal filter */
-		type_gps_bin_cfg_nav5_packet_t cfg_nav5_packet;
-		memset(&cfg_nav5_packet, 0, sizeof(cfg_nav5_packet));
+	cfg_rate_packet.clsID		= UBX_CLASS_CFG;
+	cfg_rate_packet.msgID		= UBX_MESSAGE_CFG_RATE;
+	cfg_rate_packet.length		= UBX_CFG_RATE_LENGTH;
+	cfg_rate_packet.measRate	= UBX_CFG_RATE_PAYLOAD_MEASINTERVAL;
+	cfg_rate_packet.navRate		= UBX_CFG_RATE_PAYLOAD_NAVRATE;
+	cfg_rate_packet.timeRef		= UBX_CFG_RATE_PAYLOAD_TIMEREF;
 
-		_clsID_needed = UBX_CLASS_CFG;
-		_msgID_needed = UBX_MESSAGE_CFG_NAV5;
+	send_config_packet(_fd, (uint8_t *)&cfg_rate_packet, sizeof(cfg_rate_packet));
 
-		cfg_nav5_packet.clsID        = UBX_CLASS_CFG;
-		cfg_nav5_packet.msgID        = UBX_MESSAGE_CFG_NAV5;
-		cfg_nav5_packet.length       = UBX_CFG_NAV5_LENGTH;
-		cfg_nav5_packet.mask         = UBX_CFG_NAV5_PAYLOAD_MASK;
-		cfg_nav5_packet.dynModel     = UBX_CFG_NAV5_PAYLOAD_DYNMODEL;
-		cfg_nav5_packet.fixMode      = UBX_CFG_NAV5_PAYLOAD_FIXMODE;
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: configuration failed: RATE");
+		return 1;
+	}
 
-		send_config_packet(_fd, (uint8_t*)&cfg_nav5_packet, sizeof(cfg_nav5_packet));
-		if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
-			/* try next baudrate */
-			continue;
-		}
+	/* send a NAV5 message to set the options for the internal filter */
+	type_gps_bin_cfg_nav5_packet_t cfg_nav5_packet;
+	memset(&cfg_nav5_packet, 0, sizeof(cfg_nav5_packet));
+
+	_message_class_needed = UBX_CLASS_CFG;
+	_message_id_needed = UBX_MESSAGE_CFG_NAV5;
+
+	cfg_nav5_packet.clsID        = UBX_CLASS_CFG;
+	cfg_nav5_packet.msgID        = UBX_MESSAGE_CFG_NAV5;
+	cfg_nav5_packet.length       = UBX_CFG_NAV5_LENGTH;
+	cfg_nav5_packet.mask         = UBX_CFG_NAV5_PAYLOAD_MASK;
+	cfg_nav5_packet.dynModel     = UBX_CFG_NAV5_PAYLOAD_DYNMODEL;
+	cfg_nav5_packet.fixMode      = UBX_CFG_NAV5_PAYLOAD_FIXMODE;
+
+	send_config_packet(_fd, (uint8_t *)&cfg_nav5_packet, sizeof(cfg_nav5_packet));
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: configuration failed: NAV5");
+		return 1;
+	}
+
+	/* configure message rates */
+	/* the last argument is divisor for measurement rate (set by CFG RATE), i.e. 1 means 5Hz */
+	configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_POSLLH, 1);
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: msg rate configuration failed: NAV POSLLH");
+		return 1;
+	}
+
+	configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_TIMEUTC, 1);
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: msg rate configuration failed: NAV TIMEUTC");
+		return 1;
+	}
 
-		configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_POSLLH,
-			UBX_CFG_MSG_PAYLOAD_RATE1_5HZ);
-		/* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-		configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_TIMEUTC,
-			1);
-		// /* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-		configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_SOL,
-			1);
-		// /* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-		configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_VELNED,
-			1);
-		// /* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-		// configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_DOP,
-		// 	0);
-		// /* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-		configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_SVINFO,
-			0);
-		// /* insist of receiving the ACK for this packet */
-		// if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0)
-		// 	continue;
-
-		_waiting_for_ack = false;
-		return 0;
+	configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_SOL, 1);
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: msg rate configuration failed: NAV SOL");
+		return 1;
+	}
+
+	configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_VELNED, 1);
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: msg rate configuration failed: NAV VELNED");
+		return 1;
+	}
+
+	configure_message_rate(UBX_CLASS_NAV, UBX_MESSAGE_NAV_SVINFO, 5);
+
+	if (wait_for_ack(UBX_CONFIG_TIMEOUT) < 0) {
+		warnx("ubx: msg rate configuration failed: NAV SVINFO");
+		return 1;
 	}
-	return -1;
+
+	_configured = true;
+	return 0;
 }
 
 int
 UBX::wait_for_ack(unsigned timeout)
 {
 	_waiting_for_ack = true;
-	int ret = receive(timeout);
-	_waiting_for_ack = false;
-	return ret;
+	uint64_t time_started = hrt_absolute_time();
+
+	while (hrt_absolute_time() < time_started + timeout * 1000) {
+		if (receive(timeout) > 0) {
+			if (!_waiting_for_ack) {
+				return 1;
+			}
+
+		} else {
+			return -1;	// timeout or error receiving, or NAK
+		}
+	}
+
+	return -1;	// timeout
 }
 
 int
@@ -224,56 +258,61 @@ UBX::receive(unsigned timeout)
 	fds[0].fd = _fd;
 	fds[0].events = POLLIN;
 
-	uint8_t buf[32];
+	uint8_t buf[128];
 
 	/* timeout additional to poll */
 	uint64_t time_started = hrt_absolute_time();
 
-	int j = 0;
 	ssize_t count = 0;
 
-	while (true) {
+	bool handled = false;
 
-		/* pass received bytes to the packet decoder */
-		while (j < count) {
-			if (parse_char(buf[j]) > 0) {
-				/* return to configure during configuration or to the gps driver during normal work
-				 * if a packet has arrived */
-				 if (handle_message() > 0)
-					return 1;
-			}
-			/* in case we keep trying but only get crap from GPS */
-			if (time_started + timeout*1000 < hrt_absolute_time() ) {
-				return -1;
-			}
-			j++;
-		}
-
-		/* everything is read */
-		j = count = 0;
+	while (true) {
 
-		/* then poll for new data */
-		int ret = ::poll(fds, sizeof(fds) / sizeof(fds[0]), timeout);
+		/* poll for new data, wait for only UBX_PACKET_TIMEOUT (2ms) if something already received */
+		int ret = poll(fds, sizeof(fds) / sizeof(fds[0]), handled ? UBX_PACKET_TIMEOUT : timeout);
 
 		if (ret < 0) {
 			/* something went wrong when polling */
+			warnx("ubx: poll error");
 			return -1;
 
 		} else if (ret == 0) {
-			/* Timeout */
-			return -1;
+			/* return success after short delay after receiving a packet or timeout after long delay */
+			if (handled) {
+				return 1;
+
+			} else {
+				return -1;
+			}
 
 		} else if (ret > 0) {
 			/* if we have new data from GPS, go handle it */
 			if (fds[0].revents & POLLIN) {
 				/*
 				 * We are here because poll says there is some data, so this
-				 * won't block even on a blocking device.  If more bytes are
-				 * available, we'll go back to poll() again...
+				 * won't block even on a blocking device. But don't read immediately
+				 * by 1-2 bytes, wait for some more data to save expensive read() calls.
+				 * If more bytes are available, we'll go back to poll() again.
 				 */
-				count = ::read(_fd, buf, sizeof(buf));
+				usleep(UBX_WAIT_BEFORE_READ * 1000);
+				count = read(_fd, buf, sizeof(buf));
+
+				/* pass received bytes to the packet decoder */
+				for (int i = 0; i < count; i++) {
+					if (parse_char(buf[i]) > 0) {
+						if (handle_message() > 0)
+							handled = true;
+					}
+				}
 			}
 		}
+
+		/* abort after timeout if no useful packets received */
+		if (time_started + timeout * 1000 < hrt_absolute_time()) {
+			warnx("ubx: timeout - no useful messages");
+			return -1;
+		}
 	}
 }
 
@@ -282,410 +321,304 @@ UBX::parse_char(uint8_t b)
 {
 	switch (_decode_state) {
 		/* First, look for sync1 */
-		case UBX_DECODE_UNINIT:
-			if (b == UBX_SYNC1) {
-				_decode_state = UBX_DECODE_GOT_SYNC1;
-			}
-			break;
-		/* Second, look for sync2 */
-		case UBX_DECODE_GOT_SYNC1:
-			if (b == UBX_SYNC2) {
-				_decode_state = UBX_DECODE_GOT_SYNC2;
-			} else {
-				/* Second start symbol was wrong, reset state machine */
-				decode_init();
-			}
-			break;
-		/* Now look for class */
-		case UBX_DECODE_GOT_SYNC2:
-			/* everything except sync1 and sync2 needs to be added to the checksum */
-			add_byte_to_checksum(b);
-			/* check for known class */
-			switch (b) {
-				case UBX_CLASS_ACK:
-					_decode_state = UBX_DECODE_GOT_CLASS;
-					_message_class = ACK;
-					break;
+	case UBX_DECODE_UNINIT:
+		if (b == UBX_SYNC1) {
+			_decode_state = UBX_DECODE_GOT_SYNC1;
+		}
 
-				case UBX_CLASS_NAV:
-					_decode_state = UBX_DECODE_GOT_CLASS;
-					_message_class = NAV;
-					break;
+		break;
 
-//				case UBX_CLASS_RXM:
-//					_decode_state = UBX_DECODE_GOT_CLASS;
-//					_message_class = RXM;
-//					break;
+		/* Second, look for sync2 */
+	case UBX_DECODE_GOT_SYNC1:
+		if (b == UBX_SYNC2) {
+			_decode_state = UBX_DECODE_GOT_SYNC2;
+
+		} else {
+			/* Second start symbol was wrong, reset state machine */
+			decode_init();
+			/* don't return error, it can be just false sync1 */
+		}
 
-				case UBX_CLASS_CFG:
-					_decode_state = UBX_DECODE_GOT_CLASS;
-					_message_class = CFG;
-					break;
-				default: //unknown class: reset state machine
-					decode_init();
-					break;
-			}
-			break;
-		case UBX_DECODE_GOT_CLASS:
-			add_byte_to_checksum(b);
-			switch (_message_class) {
-				case NAV:
-					switch (b) {
-					case UBX_MESSAGE_NAV_POSLLH:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = NAV_POSLLH;
-						break;
-
-					case UBX_MESSAGE_NAV_SOL:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = NAV_SOL;
-						break;
-
-					case UBX_MESSAGE_NAV_TIMEUTC:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = NAV_TIMEUTC;
-						break;
-
-//					case UBX_MESSAGE_NAV_DOP:
-//						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-//						_message_id = NAV_DOP;
-//						break;
-
-					case UBX_MESSAGE_NAV_SVINFO:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = NAV_SVINFO;
-						break;
-
-					case UBX_MESSAGE_NAV_VELNED:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = NAV_VELNED;
-						break;
-
-					default: //unknown class: reset state machine, should not happen
-						decode_init();
-						break;
-					}
-					break;
-//				case RXM:
-//					switch (b) {
-//					case UBX_MESSAGE_RXM_SVSI:
-//						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-//						_message_id = RXM_SVSI;
-//						break;
-//
-//					default: //unknown class: reset state machine, should not happen
-//						decode_init();
-//						break;
-//					}
-//					break;
-
-				case CFG:
-					switch (b) {
-					case UBX_MESSAGE_CFG_NAV5:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = CFG_NAV5;
-						break;
-
-					default: //unknown class: reset state machine, should not happen
-						decode_init();
-						break;
-					}
-					break;
+		break;
 
-				case ACK:
-					switch (b) {
-					case UBX_MESSAGE_ACK_ACK:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = ACK_ACK;
-						break;
-					case UBX_MESSAGE_ACK_NAK:
-						_decode_state = UBX_DECODE_GOT_MESSAGEID;
-						_message_id = ACK_NAK;
-						break;
-					default: //unknown class: reset state machine, should not happen
-						decode_init();
-						break;
-					}
-					break;
-				default: //should not happen because we set the class
-					warnx("UBX Error, we set a class that we don't know");
-					decode_init();
-//					config_needed = true;
-					break;
-				}
-				break;
-			case UBX_DECODE_GOT_MESSAGEID:
-				add_byte_to_checksum(b);
-				_payload_size = b; //this is the first length byte
-				_decode_state = UBX_DECODE_GOT_LENGTH1;
-				break;
-			case UBX_DECODE_GOT_LENGTH1:
-				add_byte_to_checksum(b);
-				_payload_size += b << 8; // here comes the second byte of length
-				_decode_state = UBX_DECODE_GOT_LENGTH2;
-				break;
-			case UBX_DECODE_GOT_LENGTH2:
-				/* Add to checksum if not yet at checksum byte */
-				if (_rx_count < _payload_size)
-					add_byte_to_checksum(b);
-					_rx_buffer[_rx_count] = b;
-					/* once the payload has arrived, we can process the information */
-					if (_rx_count >= _payload_size + 1) { //+1 because of 2 checksum bytes
-
-						/* compare checksum */
-						if (_rx_ck_a == _rx_buffer[_rx_count-1] && _rx_ck_b == _rx_buffer[_rx_count]) {
-							return 1;
-						} else {
-							decode_init();
-							return -1;
-							warnx("ubx: Checksum wrong");
-						}
+		/* Now look for class */
+	case UBX_DECODE_GOT_SYNC2:
+		/* everything except sync1 and sync2 needs to be added to the checksum */
+		add_byte_to_checksum(b);
+		_message_class = b;
+		_decode_state = UBX_DECODE_GOT_CLASS;
+		break;
 
-						return 1;
-					} else if (_rx_count < RECV_BUFFER_SIZE) {
-						_rx_count++;
-					} else {
-						warnx("ubx: buffer full");
-						decode_init();
-						return -1;
-					}
-				break;
-		default:
-			break;
-	}
-	return 0; //XXX ?
-}
+	case UBX_DECODE_GOT_CLASS:
+		add_byte_to_checksum(b);
+		_message_id = b;
+		_decode_state = UBX_DECODE_GOT_MESSAGEID;
+		break;
 
+	case UBX_DECODE_GOT_MESSAGEID:
+		add_byte_to_checksum(b);
+		_payload_size = b; //this is the first length byte
+		_decode_state = UBX_DECODE_GOT_LENGTH1;
+		break;
 
-int
-UBX::handle_message()
-{
-	int ret = 0;
+	case UBX_DECODE_GOT_LENGTH1:
+		add_byte_to_checksum(b);
+		_payload_size += b << 8; // here comes the second byte of length
+		_decode_state = UBX_DECODE_GOT_LENGTH2;
+		break;
 
-	switch (_message_id) { //this enum is unique for all ids --> no need to check the class
-		case NAV_POSLLH: {
-//			printf("GOT NAV_POSLLH MESSAGE\n");
-			if (!_waiting_for_ack) {
-				gps_bin_nav_posllh_packet_t *packet = (gps_bin_nav_posllh_packet_t *) _rx_buffer;
+	case UBX_DECODE_GOT_LENGTH2:
 
-				_gps_position->lat = packet->lat;
-				_gps_position->lon = packet->lon;
-				_gps_position->alt = packet->height_msl;
+		/* Add to checksum if not yet at checksum byte */
+		if (_rx_count < _payload_size)
+			add_byte_to_checksum(b);
 
-				_gps_position->eph_m = (float)packet->hAcc * 1e-3f; // from mm to m
-				_gps_position->epv_m = (float)packet->vAcc * 1e-3f; // from mm to m
+		_rx_buffer[_rx_count] = b;
 
-				_rate_count_lat_lon++;
+		/* once the payload has arrived, we can process the information */
+		if (_rx_count >= _payload_size + 1) { //+1 because of 2 checksum bytes
+			/* compare checksum */
+			if (_rx_ck_a == _rx_buffer[_rx_count - 1] && _rx_ck_b == _rx_buffer[_rx_count]) {
+				decode_init();
+				return 1;	// message received successfully
 
-				/* Add timestamp to finish the report */
-				_gps_position->timestamp_position = hrt_absolute_time();
-				/* only return 1 when new position is available */
-				ret = 1;
+			} else {
+				warnx("ubx: checksum wrong");
+				decode_init();
+				return -1;
 			}
-			break;
+
+		} else if (_rx_count < RECV_BUFFER_SIZE) {
+			_rx_count++;
+
+		} else {
+			warnx("ubx: buffer full");
+			decode_init();
+			return -1;
 		}
 
-		case NAV_SOL: {
-//			printf("GOT NAV_SOL MESSAGE\n");
-			if (!_waiting_for_ack) {
-				gps_bin_nav_sol_packet_t *packet = (gps_bin_nav_sol_packet_t *) _rx_buffer;
+		break;
 
-				_gps_position->fix_type = packet->gpsFix;
-				_gps_position->s_variance_m_s = packet->sAcc;
-				_gps_position->p_variance_m = packet->pAcc;
+	default:
+		break;
+	}
 
-				_gps_position->timestamp_variance = hrt_absolute_time();
-			}
-			break;
-		}
+	return 0;	// message decoding in progress
+}
 
-//		case NAV_DOP: {
-////		printf("GOT NAV_DOP MESSAGE\n");
-//			gps_bin_nav_dop_packet_t *packet = (gps_bin_nav_dop_packet_t *) _rx_buffer;
-//
-//			_gps_position->eph_m =  packet->hDOP;
-//			_gps_position->epv =  packet->vDOP;
-//
-//			_gps_position->timestamp_posdilution = hrt_absolute_time();
-//
-//			_new_nav_dop = true;
-//
-//			break;
-//		}
-
-		case NAV_TIMEUTC: {
-//			printf("GOT NAV_TIMEUTC MESSAGE\n");
 
-			if (!_waiting_for_ack) {
-				gps_bin_nav_timeutc_packet_t *packet = (gps_bin_nav_timeutc_packet_t *) _rx_buffer;
 
-				//convert to unix timestamp
-				struct tm timeinfo;
-				timeinfo.tm_year = packet->year - 1900;
-				timeinfo.tm_mon = packet->month - 1;
-				timeinfo.tm_mday = packet->day;
-				timeinfo.tm_hour = packet->hour;
-				timeinfo.tm_min = packet->min;
-				timeinfo.tm_sec = packet->sec;
+int
+UBX::handle_message()
+{
+	int ret = 0;
 
-				time_t epoch = mktime(&timeinfo);
+	if (_configured) {
+		/* handle only info messages when configured */
+		switch (_message_class) {
+		case UBX_CLASS_NAV:
+			switch (_message_id) {
+			case UBX_MESSAGE_NAV_POSLLH: {
+					// printf("GOT NAV_POSLLH\n");
+					gps_bin_nav_posllh_packet_t *packet = (gps_bin_nav_posllh_packet_t *) _rx_buffer;
 
-				_gps_position->time_gps_usec = (uint64_t)epoch * 1000000; //TODO: test this
-				_gps_position->time_gps_usec += (uint64_t)(packet->time_nanoseconds * 1e-3f);
+					_gps_position->lat = packet->lat;
+					_gps_position->lon = packet->lon;
+					_gps_position->alt = packet->height_msl;
+					_gps_position->eph_m = (float)packet->hAcc * 1e-3f; // from mm to m
+					_gps_position->epv_m = (float)packet->vAcc * 1e-3f; // from mm to m
+					_gps_position->timestamp_position = hrt_absolute_time();
 
-				_gps_position->timestamp_time = hrt_absolute_time();
-			}
-			break;
-		}
+					_rate_count_lat_lon++;
 
-		case NAV_SVINFO: {
-//			printf("GOT NAV_SVINFO MESSAGE\n");
+					ret = 1;
+					break;
+				}
 
-			if (!_waiting_for_ack) {
-				//this is a more complicated message: the length depends on the number of satellites. This number is extracted from the first part of the message
-				const int length_part1 = 8;
-				char _rx_buffer_part1[length_part1];
-				memcpy(_rx_buffer_part1, _rx_buffer, length_part1);
-				gps_bin_nav_svinfo_part1_packet_t *packet_part1 = (gps_bin_nav_svinfo_part1_packet_t *) _rx_buffer_part1;
+			case UBX_MESSAGE_NAV_SOL: {
+					// printf("GOT NAV_SOL\n");
+					gps_bin_nav_sol_packet_t *packet = (gps_bin_nav_sol_packet_t *) _rx_buffer;
 
-				//read checksum
-				const int length_part3 = 2;
-				char _rx_buffer_part3[length_part3];
-				memcpy(_rx_buffer_part3, &(_rx_buffer[_rx_count - 1]), length_part3);
+					_gps_position->fix_type = packet->gpsFix;
+					_gps_position->s_variance_m_s = packet->sAcc;
+					_gps_position->p_variance_m = packet->pAcc;
+					_gps_position->timestamp_variance = hrt_absolute_time();
 
-				//definitions needed to read numCh elements from the buffer:
-				const int length_part2 = 12;
-				gps_bin_nav_svinfo_part2_packet_t *packet_part2;
-				char _rx_buffer_part2[length_part2]; //for temporal storage
+					ret = 1;
+					break;
+				}
 
-				uint8_t satellites_used = 0;
-				int i;
+			case UBX_MESSAGE_NAV_TIMEUTC: {
+					// printf("GOT NAV_TIMEUTC\n");
+					gps_bin_nav_timeutc_packet_t *packet = (gps_bin_nav_timeutc_packet_t *) _rx_buffer;
+
+					/* convert to unix timestamp */
+					struct tm timeinfo;
+					timeinfo.tm_year = packet->year - 1900;
+					timeinfo.tm_mon = packet->month - 1;
+					timeinfo.tm_mday = packet->day;
+					timeinfo.tm_hour = packet->hour;
+					timeinfo.tm_min = packet->min;
+					timeinfo.tm_sec = packet->sec;
+					time_t epoch = mktime(&timeinfo);
+
+#ifndef CONFIG_RTC
+					//Since we lack a hardware RTC, set the system time clock based on GPS UTC
+					//TODO generalize this by moving into gps.cpp?
+					timespec ts;
+					ts.tv_sec = epoch;
+					ts.tv_nsec = packet->time_nanoseconds;
+					clock_settime(CLOCK_REALTIME, &ts);
+#endif
+
+					_gps_position->time_gps_usec = (uint64_t)epoch * 1000000; //TODO: test this
+					_gps_position->time_gps_usec += (uint64_t)(packet->time_nanoseconds * 1e-3f);
+					_gps_position->timestamp_time = hrt_absolute_time();
 
-				for (i = 0; i < packet_part1->numCh; i++) { //for each channel
+					ret = 1;
+					break;
+				}
 
-					/* Get satellite information from the buffer */
-					memcpy(_rx_buffer_part2, &(_rx_buffer[length_part1 + i * length_part2]), length_part2);
-					packet_part2 = (gps_bin_nav_svinfo_part2_packet_t *) _rx_buffer_part2;
+			case UBX_MESSAGE_NAV_SVINFO: {
+					//printf("GOT NAV_SVINFO\n");
+					const int length_part1 = 8;
+					gps_bin_nav_svinfo_part1_packet_t *packet_part1 = (gps_bin_nav_svinfo_part1_packet_t *) _rx_buffer;
+					const int length_part2 = 12;
+					gps_bin_nav_svinfo_part2_packet_t *packet_part2;
 
+					uint8_t satellites_used = 0;
+					int i;
 
-					/* Write satellite information in the global storage */
-					_gps_position->satellite_prn[i] = packet_part2->svid;
+					//printf("Number of Channels: %d\n", packet_part1->numCh);
+					for (i = 0; i < packet_part1->numCh; i++) {
+						/* set pointer to sattelite_i information */
+						packet_part2 = (gps_bin_nav_svinfo_part2_packet_t *) & (_rx_buffer[length_part1 + i * length_part2]);
 
-					//if satellite information is healthy store the data
-					uint8_t unhealthy = packet_part2->flags & 1 << 4; //flags is a bitfield
+						/* write satellite information to global storage */
+						uint8_t sv_used = packet_part2->flags & 0x01;
 
-					if (!unhealthy) {
-						if ((packet_part2->flags) & 1) { //flags is a bitfield
-							_gps_position->satellite_used[i] = 1;
+						if (sv_used) {
+							/* count SVs used for NAV */
 							satellites_used++;
-
-						} else {
-							_gps_position->satellite_used[i] = 0;
 						}
 
+						/* record info for all channels, whether or not the SV is used for NAV */
+						_gps_position->satellite_used[i] = sv_used;
 						_gps_position->satellite_snr[i] = packet_part2->cno;
 						_gps_position->satellite_elevation[i] = (uint8_t)(packet_part2->elev);
 						_gps_position->satellite_azimuth[i] = (uint8_t)((float)packet_part2->azim * 255.0f / 360.0f);
+						_gps_position->satellite_prn[i] = packet_part2->svid;
+						//printf("SAT %d: %d %d %d %d\n", i, (int)sv_used, (int)packet_part2->cno, (int)(uint8_t)(packet_part2->elev), (int)packet_part2->svid);
+					}
 
-					} else {
+					for (i = packet_part1->numCh; i < 20; i++) {
+						/* unused channels have to be set to zero for e.g. MAVLink */
+						_gps_position->satellite_prn[i] = 0;
 						_gps_position->satellite_used[i] = 0;
 						_gps_position->satellite_snr[i] = 0;
 						_gps_position->satellite_elevation[i] = 0;
 						_gps_position->satellite_azimuth[i] = 0;
 					}
 
-				}
+					_gps_position->satellites_visible = satellites_used; // visible ~= used but we are interested in the used ones
+
+					if (packet_part1->numCh > 0) {
+						_gps_position->satellite_info_available = true;
+
+					} else {
+						_gps_position->satellite_info_available = false;
+					}
+
+					_gps_position->timestamp_satellites = hrt_absolute_time();
 
-				for (i = packet_part1->numCh; i < 20; i++) { //these channels are unused
-					/* Unused channels have to be set to zero for e.g. MAVLink */
-					_gps_position->satellite_prn[i] = 0;
-					_gps_position->satellite_used[i] = 0;
-					_gps_position->satellite_snr[i] = 0;
-					_gps_position->satellite_elevation[i] = 0;
-					_gps_position->satellite_azimuth[i] = 0;
+					ret = 1;
+					break;
 				}
-				_gps_position->satellites_visible = satellites_used; // visible ~= used but we are interested in the used ones
 
-				/* set timestamp if any sat info is available */
-				if (packet_part1->numCh > 0) {
-					_gps_position->satellite_info_available = true;
-				} else {
-					_gps_position->satellite_info_available = false;
+			case UBX_MESSAGE_NAV_VELNED: {
+					// printf("GOT NAV_VELNED\n");
+					gps_bin_nav_velned_packet_t *packet = (gps_bin_nav_velned_packet_t *) _rx_buffer;
+
+					_gps_position->vel_m_s   = (float)packet->speed * 1e-2f;
+					_gps_position->vel_n_m_s = (float)packet->velN * 1e-2f; /* NED NORTH velocity */
+					_gps_position->vel_e_m_s = (float)packet->velE * 1e-2f; /* NED EAST velocity */
+					_gps_position->vel_d_m_s = (float)packet->velD * 1e-2f; /* NED DOWN velocity */
+					_gps_position->cog_rad   = (float)packet->heading * M_DEG_TO_RAD_F * 1e-5f;
+					_gps_position->c_variance_rad = (float)packet->cAcc * M_DEG_TO_RAD_F * 1e-5f;
+					_gps_position->vel_ned_valid = true;
+					_gps_position->timestamp_velocity = hrt_absolute_time();
+
+					_rate_count_vel++;
+
+					ret = 1;
+					break;
 				}
-				_gps_position->timestamp_satellites = hrt_absolute_time();
+
+			default:
+				break;
 			}
 
 			break;
-		}
 
-		case NAV_VELNED: {
-
-			if (!_waiting_for_ack) {
-				/* 35.15 NAV-VELNED (0x01 0x12) message (page 181 / 210 of reference manual */
-				gps_bin_nav_velned_packet_t *packet = (gps_bin_nav_velned_packet_t *) _rx_buffer;
-
-				_gps_position->vel_m_s   = (float)packet->speed * 1e-2f;
-				_gps_position->vel_n_m_s = (float)packet->velN * 1e-2f; /* NED NORTH velocity */
-				_gps_position->vel_e_m_s = (float)packet->velE * 1e-2f; /* NED EAST velocity */
-				_gps_position->vel_d_m_s = (float)packet->velD * 1e-2f; /* NED DOWN velocity */
-				_gps_position->cog_rad   = (float)packet->heading * M_DEG_TO_RAD_F * 1e-5f;
-				_gps_position->c_variance_rad = (float)packet->cAcc * M_DEG_TO_RAD_F * 1e-5f;
-				_gps_position->vel_ned_valid = true;
-				_gps_position->timestamp_velocity = hrt_absolute_time();
-
-				_rate_count_vel++;
+		case UBX_CLASS_ACK: {
+				/* ignore ACK when already configured */
+				ret = 1;
+				break;
 			}
 
+		default:
 			break;
 		}
 
-//		case RXM_SVSI: {
-//				printf("GOT RXM_SVSI MESSAGE\n");
-//				const int length_part1 = 7;
-//				char _rx_buffer_part1[length_part1];
-//				memcpy(_rx_buffer_part1, _rx_buffer, length_part1);
-//				gps_bin_rxm_svsi_packet_t *packet = (gps_bin_rxm_svsi_packet_t *) _rx_buffer_part1;
-//
-//				_gps_position->satellites_visible = packet->numVis;
-//				_gps_position->counter++;
-//				_last_message_timestamps[RXM_SVSI - 1] = hrt_absolute_time();
-//
-//			break;
-//		}
-		case ACK_ACK: {
-//			printf("GOT ACK_ACK\n");
-			gps_bin_ack_ack_packet_t *packet = (gps_bin_ack_ack_packet_t *) _rx_buffer;
-
-			if (_waiting_for_ack) {
-				if (packet->clsID == _clsID_needed && packet->msgID == _msgID_needed) {
-					ret = 1;
-				}
+		if (ret == 0) {
+			/* message not handled */
+			warnx("ubx: unknown message received: 0x%02x-0x%02x", (unsigned)_message_class, (unsigned)_message_id);
+
+			hrt_abstime t = hrt_absolute_time();
+
+			if (t > _disable_cmd_last + DISABLE_MSG_INTERVAL) {
+				/* don't attempt for every message to disable, some might not be disabled */
+				_disable_cmd_last = t;
+				warnx("ubx: disabling message 0x%02x-0x%02x", (unsigned)_message_class, (unsigned)_message_id);
+				configure_message_rate(_message_class, _message_id, 0);
 			}
 		}
-		break;
 
-		case ACK_NAK: {
-//			printf("GOT ACK_NAK\n");
-			warnx("UBX: Received: Not Acknowledged");
-			/* configuration obviously not successful */
-			ret = -1;
-			break;
-		}
+	} else {
+		/* handle only ACK while configuring */
+		if (_message_class == UBX_CLASS_ACK) {
+			switch (_message_id) {
+			case UBX_MESSAGE_ACK_ACK: {
+					// printf("GOT ACK_ACK\n");
+					gps_bin_ack_ack_packet_t *packet = (gps_bin_ack_ack_packet_t *) _rx_buffer;
+
+					if (_waiting_for_ack) {
+						if (packet->clsID == _message_class_needed && packet->msgID == _message_id_needed) {
+							_waiting_for_ack = false;
+							ret = 1;
+						}
+					}
 
-		default: //we don't know the message
-			warnx("UBX: Unknown message received: %d-%d\n",_message_class,_message_id);
-			if (_disable_cmd_counter++ == 0) {
-				// Don't attempt for every message to disable, some might not be disabled */
-				warnx("Disabling message 0x%02x 0x%02x", (unsigned)_message_class, (unsigned)_message_id);
-				configure_message_rate(_message_class, _message_id, 0);
+					break;
+				}
+
+			case UBX_MESSAGE_ACK_NAK: {
+					// printf("GOT ACK_NAK\n");
+					warnx("ubx: not acknowledged");
+					/* configuration obviously not successful */
+					_waiting_for_ack = false;
+					ret = -1;
+					break;
+				}
+
+			default:
+				break;
 			}
-		return ret;
-			ret = -1;
-			break;
 		}
-	// end if _rx_count high enough
+	}
+
 	decode_init();
-	return ret; //XXX?
+	return ret;
 }
 
 void
@@ -695,9 +628,8 @@ UBX::decode_init(void)
 	_rx_ck_b = 0;
 	_rx_count = 0;
 	_decode_state = UBX_DECODE_UNINIT;
-	_message_class = CLASS_UNKNOWN;
-	_message_id = ID_UNKNOWN;
 	_payload_size = 0;
+	/* don't reset _message_class, _message_id, _rx_buffer leave it for message handler */
 }
 
 void
@@ -708,23 +640,24 @@ UBX::add_byte_to_checksum(uint8_t b)
 }
 
 void
-UBX::add_checksum_to_message(uint8_t* message, const unsigned length)
+UBX::add_checksum_to_message(uint8_t *message, const unsigned length)
 {
 	uint8_t ck_a = 0;
 	uint8_t ck_b = 0;
 	unsigned i;
 
-	for (i = 0; i < length-2; i++) {
+	for (i = 0; i < length - 2; i++) {
 		ck_a = ck_a + message[i];
 		ck_b = ck_b + ck_a;
 	}
-	/* The checksum is written to the last to bytes of a message */
-	message[length-2] = ck_a;
-	message[length-1] = ck_b;
+
+	/* the checksum is written to the last to bytes of a message */
+	message[length - 2] = ck_a;
+	message[length - 1] = ck_b;
 }
 
 void
-UBX::add_checksum(uint8_t* message, const unsigned length, uint8_t &ck_a, uint8_t &ck_b)
+UBX::add_checksum(uint8_t *message, const unsigned length, uint8_t &ck_a, uint8_t &ck_b)
 {
 	for (unsigned i = 0; i < length; i++) {
 		ck_a = ck_a + message[i];
@@ -735,11 +668,11 @@ UBX::add_checksum(uint8_t* message, const unsigned length, uint8_t &ck_a, uint8_
 void
 UBX::configure_message_rate(uint8_t msg_class, uint8_t msg_id, uint8_t rate)
 {
-    struct ubx_cfg_msg_rate msg;
-    msg.msg_class	= msg_class;
-    msg.msg_id		= msg_id;
-    msg.rate		= rate;
-    send_message(CFG, UBX_MESSAGE_CFG_MSG, &msg, sizeof(msg));
+	struct ubx_cfg_msg_rate msg;
+	msg.msg_class	= msg_class;
+	msg.msg_id		= msg_id;
+	msg.rate		= rate;
+	send_message(UBX_CLASS_CFG, UBX_MESSAGE_CFG_MSG, &msg, sizeof(msg));
 }
 
 void
@@ -747,36 +680,36 @@ UBX::send_config_packet(const int &fd, uint8_t *packet, const unsigned length)
 {
 	ssize_t ret = 0;
 
-	/* Calculate the checksum now */
+	/* calculate the checksum now */
 	add_checksum_to_message(packet, length);
 
 	const uint8_t sync_bytes[] = {UBX_SYNC1, UBX_SYNC2};
 
-	/* Start with the two sync bytes */
+	/* start with the two sync bytes */
 	ret += write(fd, sync_bytes, sizeof(sync_bytes));
 	ret += write(fd, packet, length);
 
 	if (ret != (int)length + (int)sizeof(sync_bytes)) // XXX is there a neater way to get rid of the unsigned signed warning?
-		warnx("ubx: config write fail");
+		warnx("ubx: configuration write fail");
 }
 
 void
 UBX::send_message(uint8_t msg_class, uint8_t msg_id, void *msg, uint8_t size)
 {
 	struct ubx_header header;
-	uint8_t ck_a=0, ck_b=0;
+	uint8_t ck_a = 0, ck_b = 0;
 	header.sync1 = UBX_SYNC1;
 	header.sync2 = UBX_SYNC2;
 	header.msg_class = msg_class;
 	header.msg_id    = msg_id;
 	header.length    = size;
 
-	add_checksum((uint8_t *)&header.msg_class, sizeof(header)-2, ck_a, ck_b);
+	add_checksum((uint8_t *)&header.msg_class, sizeof(header) - 2, ck_a, ck_b);
 	add_checksum((uint8_t *)msg, size, ck_a, ck_b);
 
-	// Configure receive check
-	_clsID_needed = msg_class;
-	_msgID_needed = msg_id;
+	/* configure ACK check */
+	_message_class_needed = msg_class;
+	_message_id_needed = msg_id;
 
 	write(_fd, (const char *)&header, sizeof(header));
 	write(_fd, (const char *)msg, size);
diff --git a/src/drivers/gps/ubx.h b/src/drivers/gps/ubx.h
index 5a433642c..79a904f4a 100644
--- a/src/drivers/gps/ubx.h
+++ b/src/drivers/gps/ubx.h
@@ -1,8 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2008-2013 PX4 Development Team. All rights reserved.
- *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
- *           Julian Oes <joes@student.ethz.ch>
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,7 +31,17 @@
  *
  ****************************************************************************/
 
-/* @file U-Blox protocol definitions */
+/**
+ * @file ubx.h
+ *
+ * U-Blox protocol definition. Following u-blox 6/7 Receiver Description
+ * including Prototol Specification.
+ *
+ * @author Thomas Gubler <thomasgubler@student.ethz.ch>
+ * @author Julian Oes <joes@student.ethz.ch>
+ * @author Anton Babushkin <anton.babushkin@me.com>
+ *
+ */
 
 #ifndef UBX_H_
 #define UBX_H_
@@ -51,23 +59,23 @@
 
 /* MessageIDs (the ones that are used) */
 #define UBX_MESSAGE_NAV_POSLLH 0x02
-#define UBX_MESSAGE_NAV_SOL 0x06
-#define UBX_MESSAGE_NAV_TIMEUTC 0x21
 //#define UBX_MESSAGE_NAV_DOP 0x04
-#define UBX_MESSAGE_NAV_SVINFO 0x30
+#define UBX_MESSAGE_NAV_SOL 0x06
 #define UBX_MESSAGE_NAV_VELNED 0x12
 //#define UBX_MESSAGE_RXM_SVSI 0x20
-#define UBX_MESSAGE_ACK_ACK 0x01
+#define UBX_MESSAGE_NAV_TIMEUTC 0x21
+#define UBX_MESSAGE_NAV_SVINFO 0x30
 #define UBX_MESSAGE_ACK_NAK 0x00
+#define UBX_MESSAGE_ACK_ACK 0x01
 #define UBX_MESSAGE_CFG_PRT 0x00
-#define UBX_MESSAGE_CFG_NAV5 0x24
 #define UBX_MESSAGE_CFG_MSG 0x01
 #define UBX_MESSAGE_CFG_RATE 0x08
+#define UBX_MESSAGE_CFG_NAV5 0x24
 
 #define UBX_CFG_PRT_LENGTH 20
 #define UBX_CFG_PRT_PAYLOAD_PORTID 0x01			/**< UART1 */
 #define UBX_CFG_PRT_PAYLOAD_MODE 0x000008D0		/**< 0b0000100011010000: 8N1 */
-#define UBX_CFG_PRT_PAYLOAD_BAUDRATE 38400		/**< always choose 38400 as GPS baudrate */
+#define UBX_CFG_PRT_PAYLOAD_BAUDRATE 38400		/**< choose 38400 as GPS baudrate */
 #define UBX_CFG_PRT_PAYLOAD_INPROTOMASK 0x01		/**< UBX in */
 #define UBX_CFG_PRT_PAYLOAD_OUTPROTOMASK 0x01		/**< UBX out */
 
@@ -299,44 +307,6 @@ struct ubx_cfg_msg_rate {
 // ************
 
 typedef enum {
-	UBX_CONFIG_STATE_PRT = 0,
-	UBX_CONFIG_STATE_PRT_NEW_BAUDRATE,
-	UBX_CONFIG_STATE_RATE,
-	UBX_CONFIG_STATE_NAV5,
-	UBX_CONFIG_STATE_MSG_NAV_POSLLH,
-	UBX_CONFIG_STATE_MSG_NAV_TIMEUTC,
-	UBX_CONFIG_STATE_MSG_NAV_DOP,
-	UBX_CONFIG_STATE_MSG_NAV_SVINFO,
-	UBX_CONFIG_STATE_MSG_NAV_SOL,
-	UBX_CONFIG_STATE_MSG_NAV_VELNED,
-//	UBX_CONFIG_STATE_MSG_RXM_SVSI,
-	UBX_CONFIG_STATE_CONFIGURED
-} ubx_config_state_t;
-
-typedef enum {
-	CLASS_UNKNOWN = 0,
-	NAV = 1,
-	RXM = 2,
-	ACK = 3,
-	CFG = 4
-} ubx_message_class_t;
-
-typedef enum {
-	//these numbers do NOT correspond to the message id numbers of the ubx protocol
-	ID_UNKNOWN = 0,
-	NAV_POSLLH,
-	NAV_SOL,
-	NAV_TIMEUTC,
-//	NAV_DOP,
-	NAV_SVINFO,
-	NAV_VELNED,
-//	RXM_SVSI,
-	CFG_NAV5,
-	ACK_ACK,
-	ACK_NAK,
-} ubx_message_id_t;
-
-typedef enum {
 	UBX_DECODE_UNINIT = 0,
 	UBX_DECODE_GOT_SYNC1,
 	UBX_DECODE_GOT_SYNC2,
@@ -384,7 +354,7 @@ private:
 	/**
 	 * Add the two checksum bytes to an outgoing message
 	 */
-	void			add_checksum_to_message(uint8_t* message, const unsigned length);
+	void			add_checksum_to_message(uint8_t *message, const unsigned length);
 
 	/**
 	 * Helper to send a config packet
@@ -395,25 +365,25 @@ private:
 
 	void			send_message(uint8_t msg_class, uint8_t msg_id, void *msg, uint8_t size);
 
-	void			add_checksum(uint8_t* message, const unsigned length, uint8_t &ck_a, uint8_t &ck_b);
+	void			add_checksum(uint8_t *message, const unsigned length, uint8_t &ck_a, uint8_t &ck_b);
 
 	int			wait_for_ack(unsigned timeout);
 
 	int			_fd;
 	struct vehicle_gps_position_s *_gps_position;
-	ubx_config_state_t	_config_state;
+	bool			_configured;
 	bool			_waiting_for_ack;
-	uint8_t			_clsID_needed;
-	uint8_t			_msgID_needed;
+	uint8_t			_message_class_needed;
+	uint8_t			_message_id_needed;
 	ubx_decode_state_t	_decode_state;
 	uint8_t			_rx_buffer[RECV_BUFFER_SIZE];
 	unsigned		_rx_count;
 	uint8_t			_rx_ck_a;
 	uint8_t			_rx_ck_b;
-	ubx_message_class_t	_message_class;
-	ubx_message_id_t	_message_id;
+	uint8_t			_message_class;
+	uint8_t			_message_id;
 	unsigned		_payload_size;
-	uint8_t			_disable_cmd_counter;
+	uint8_t			_disable_cmd_last;
 };
 
 #endif /* UBX_H_ */