Merge pull request #1381 from dyeldandi/ashtech_hi_freq

Ashtech GNSS receiver driver

6 files changed, 728 insertions, 2 deletions

diff --git a/src/drivers/drv_gps.h b/src/drivers/drv_gps.h
index e14f4e00d..76a211000 100644
--- a/src/drivers/drv_gps.h
+++ b/src/drivers/drv_gps.h
@@ -57,7 +57,8 @@
 typedef enum {
 	GPS_DRIVER_MODE_NONE = 0,
 	GPS_DRIVER_MODE_UBX,
-	GPS_DRIVER_MODE_MTK
+	GPS_DRIVER_MODE_MTK,
+	GPS_DRIVER_MODE_ASHTECH
 } gps_driver_mode_t;
 
 
diff --git a/src/drivers/gps/ashtech.cpp b/src/drivers/gps/ashtech.cpp
new file mode 100644
index 000000000..1b706b5b2
--- /dev/null
+++ b/src/drivers/gps/ashtech.cpp
@@ -0,0 +1,611 @@
+#include "ashtech.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <poll.h>
+#include <math.h>
+#include <string.h>
+#include <assert.h>
+#include <systemlib/err.h>
+#include <uORB/uORB.h>
+#include <uORB/topics/vehicle_gps_position.h>
+#include <uORB/topics/satellite_info.h>
+#include <drivers/drv_hrt.h>
+
+#include <fcntl.h>
+#include <math.h>
+
+ASHTECH::ASHTECH(const int &fd, struct vehicle_gps_position_s *gps_position, struct satellite_info_s *satellite_info):
+	_fd(fd),
+	_satellite_info(satellite_info),
+	_gps_position(gps_position)
+{
+	decode_init();
+	_decode_state = NME_DECODE_UNINIT;
+	_rx_buffer_bytes = 0;
+}
+
+ASHTECH::~ASHTECH()
+{
+}
+
+/*
+ * All NMEA descriptions are taken from
+ * http://www.trimble.com/OEM_ReceiverHelp/V4.44/en/NMEA-0183messages_MessageOverview.html
+ */
+
+int ASHTECH::handle_message(int len)
+{
+	char * endp;
+	
+	if (len < 7) { return 0; }
+
+	int uiCalcComma = 0;
+
+	for (int i = 0 ; i < len; i++) {
+		if (_rx_buffer[i] == ',') { uiCalcComma++; }
+	}
+
+	char *bufptr = (char *)(_rx_buffer + 6);
+
+	if ((memcmp(_rx_buffer + 3, "ZDA,", 3) == 0) && (uiCalcComma == 6)) {
+		/*
+		UTC day, month, and year, and local time zone offset
+		An example of the ZDA message string is:
+
+		$GPZDA,172809.456,12,07,1996,00,00*45
+
+		ZDA message fields
+		Field	Meaning
+		0	Message ID $GPZDA
+		1	UTC
+		2	Day, ranging between 01 and 31
+		3	Month, ranging between 01 and 12
+		4	Year
+		5	Local time zone offset from GMT, ranging from 00 through 13 hours
+		6	Local time zone offset from GMT, ranging from 00 through 59 minutes
+		7	The checksum data, always begins with *
+		Fields 5 and 6 together yield the total offset. For example, if field 5 is -5 and field 6 is +15, local time is 5 hours and 15 minutes earlier than GMT.
+		*/
+		double ashtech_time = 0.0;
+		int day = 0, month = 0, year = 0, local_time_off_hour __attribute__((unused)) = 0, local_time_off_min __attribute__((unused)) = 0;
+
+		if (bufptr && *(++bufptr) != ',') { ashtech_time = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { day = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { month = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { year = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { local_time_off_hour = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { local_time_off_min = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+
+		int ashtech_hour = ashtech_time / 10000;
+		int ashtech_minute = (ashtech_time - ashtech_hour * 10000) / 100;
+		double ashtech_sec = ashtech_time - ashtech_hour * 10000 - ashtech_minute * 100;
+		/*
+		 * convert to unix timestamp
+		 */
+		struct tm timeinfo;
+		timeinfo.tm_year = year - 1900;
+		timeinfo.tm_mon = month - 1;
+		timeinfo.tm_mday = day;
+		timeinfo.tm_hour = ashtech_hour;
+		timeinfo.tm_min = ashtech_minute;
+		timeinfo.tm_sec = int(ashtech_sec);
+		time_t epoch = mktime(&timeinfo);
+
+		_gps_position->time_gps_usec = (uint64_t)epoch * 1000000; //TODO: test this
+		_gps_position->time_gps_usec += (uint64_t)((ashtech_sec - int(ashtech_sec)) * 1e6);
+		_gps_position->timestamp_time = hrt_absolute_time();
+	}
+
+	else if ((memcmp(_rx_buffer + 3, "GGA,", 3) == 0) && (uiCalcComma == 14)) {
+		/*
+		  Time, position, and fix related data
+		  An example of the GBS message string is:
+
+		  $GPGGA,172814.0,3723.46587704,N,12202.26957864,W,2,6,1.2,18.893,M,-25.669,M,2.0,0031*4F
+
+		  Note - The data string exceeds the ASHTECH standard length.
+		  GGA message fields
+		  Field   Meaning
+		  0   Message ID $GPGGA
+		  1   UTC of position fix
+		  2   Latitude
+		  3   Direction of latitude:
+		  N: North
+		  S: South
+		  4   Longitude
+		  5   Direction of longitude:
+		  E: East
+		  W: West
+		  6   GPS Quality indicator:
+		  0: Fix not valid
+		  1: GPS fix
+		  2: Differential GPS fix, OmniSTAR VBS
+		  4: Real-Time Kinematic, fixed integers
+		  5: Real-Time Kinematic, float integers, OmniSTAR XP/HP or Location RTK
+		  7   Number of SVs in use, range from 00 through to 24+
+		  8   HDOP
+		  9   Orthometric height (MSL reference)
+		  10  M: unit of measure for orthometric height is meters
+		  11  Geoid separation
+		  12  M: geoid separation measured in meters
+		  13  Age of differential GPS data record, Type 1 or Type 9. Null field when DGPS is not used.
+		  14  Reference station ID, range 0000-4095. A null field when any reference station ID is selected and no corrections are received1.
+		  15
+		  The checksum data, always begins with *
+		  Note - If a user-defined geoid model, or an inclined
+		*/
+		double ashtech_time __attribute__((unused)) = 0.0, lat = 0.0, lon = 0.0, alt = 0.0;
+		int num_of_sv __attribute__((unused)) = 0, fix_quality = 0;
+		double hdop __attribute__((unused)) = 99.9;
+		char ns = '?', ew = '?';
+
+		if (bufptr && *(++bufptr) != ',') { ashtech_time = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { lat = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ns = *(bufptr++); }
+
+		if (bufptr && *(++bufptr) != ',') { lon = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ew = *(bufptr++); }
+
+		if (bufptr && *(++bufptr) != ',') { fix_quality = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { num_of_sv = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { hdop = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { alt = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (ns == 'S') {
+			lat = -lat;
+		}
+
+		if (ew == 'W') {
+			lon = -lon;
+		}
+
+		_gps_position->lat = (int(lat * 0.01) + (lat * 0.01 - int(lat * 0.01)) * 100.0 / 60.0) * 10000000;
+		_gps_position->lon = (int(lon * 0.01) + (lon * 0.01 - int(lon * 0.01)) * 100.0 / 60.0) * 10000000;
+		_gps_position->alt = alt * 1000;
+		_rate_count_lat_lon++;
+
+		if ((lat == 0.0) && (lon == 0.0) && (alt == 0.0)) {
+			_gps_position->fix_type = 0;
+
+		} else {
+			_gps_position->fix_type = 3 + fix_quality;
+		}
+
+		_gps_position->timestamp_position = hrt_absolute_time();
+
+		_gps_position->vel_m_s = 0;                                  /**< GPS ground speed (m/s) */
+		_gps_position->vel_n_m_s = 0;                                /**< GPS ground speed in m/s */
+		_gps_position->vel_e_m_s = 0;                                /**< GPS ground speed in m/s */
+		_gps_position->vel_d_m_s = 0;                                /**< GPS ground speed in m/s */
+		_gps_position->cog_rad =
+			0;                                  /**< Course over ground (NOT heading, but direction of movement) in rad, -PI..PI */
+		_gps_position->vel_ned_valid = true;                         /**< Flag to indicate if NED speed is valid */
+		_gps_position->c_variance_rad = 0.1;
+		_gps_position->timestamp_velocity = hrt_absolute_time();
+		return 1;
+
+	} else if ((memcmp(_rx_buffer, "$PASHR,POS,", 11) == 0) && (uiCalcComma == 18)) {
+		/*
+		Example $PASHR,POS,2,10,125410.00,5525.8138702,N,03833.9587380,E,131.555,1.0,0.0,0.007,-0.001,2.0,1.0,1.7,1.0,*34
+
+		    $PASHR,POS,d1,d2,m3,m4,c5,m6,c7,f8,f9,f10,f11,f12,f13,f14,f15,f16,s17*cc
+		    Parameter Description Range
+		      d1 Position mode 0: standalone
+		                       1: differential
+		                       2: RTK float
+		                       3: RTK fixed
+		                       5: Dead reckoning
+		                       9: SBAS (see NPT setting)
+		      d2 Number of satellite used in position fix 0-99
+		      m3 Current UTC time of position fix (hhmmss.ss) 000000.00-235959.99
+		      m4 Latitude of position (ddmm.mmmmmm) 0-90 degrees 00-59.9999999 minutes
+		      c5 Latitude sector N, S
+		      m6 Longitude of position (dddmm.mmmmmm) 0-180 degrees 00-59.9999999 minutes
+		      c7 Longitude sector E,W
+		      f8 Altitude above ellipsoid +9999.000
+		      f9 Differential age (data link age), seconds 0.0-600.0
+		      f10 True track/course over ground in degrees 0.0-359.9
+		      f11 Speed over ground in knots 0.0-999.9
+		      f12 Vertical velocity in decimeters per second +999.9
+		      f13 PDOP 0-99.9
+		      f14 HDOP 0-99.9
+		      f15 VDOP 0-99.9
+		      f16 TDOP 0-99.9
+		      s17 Reserved no data
+		      *cc Checksum
+		    */
+		bufptr = (char *)(_rx_buffer + 10);
+		double ashtech_time __attribute__((unused)) = 0.0, lat = 0.0, lon = 0.0, alt = 0.0;
+		int num_of_sv __attribute__((unused)) = 0, fix_quality = 0;
+		double track_true = 0.0, ground_speed = 0.0 , age_of_corr __attribute__((unused)) = 0.0;
+		double hdop __attribute__((unused)) = 99.9, vdop __attribute__((unused)) = 99.9,  pdop __attribute__((unused)) = 99.9, tdop __attribute__((unused)) = 99.9, vertic_vel = 0.0;
+		char ns = '?', ew = '?';
+
+		if (bufptr && *(++bufptr) != ',') { fix_quality = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { num_of_sv = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ashtech_time = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { lat = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ns = *(bufptr++); }
+
+		if (bufptr && *(++bufptr) != ',') { lon = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ew = *(bufptr++); }
+
+		if (bufptr && *(++bufptr) != ',') { alt = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { age_of_corr = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { track_true = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { ground_speed = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { vertic_vel = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { pdop = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { hdop = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { vdop = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { tdop = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (ns == 'S') {
+			lat = -lat;
+		}
+
+		if (ew == 'W') {
+			lon = -lon;
+		}
+
+		_gps_position->lat = (int(lat * 0.01) + (lat * 0.01 - int(lat * 0.01)) * 100.0 / 60.0) * 10000000;
+		_gps_position->lon = (int(lon * 0.01) + (lon * 0.01 - int(lon * 0.01)) * 100.0 / 60.0) * 10000000;
+		_gps_position->alt = alt * 1000;
+		_rate_count_lat_lon++;
+
+		if ((lat == 0.0) && (lon == 0.0) && (alt == 0.0)) {
+			_gps_position->fix_type = 0;
+
+		} else {
+			_gps_position->fix_type = 3 + fix_quality;
+		}
+
+		_gps_position->timestamp_position = hrt_absolute_time();
+
+		double track_rad = track_true * M_PI / 180.0;
+
+		double velocity_ms = ground_speed  / 1.9438445;			/** knots to m/s */
+		double velocity_north = velocity_ms * cos(track_rad);
+		double velocity_east  = velocity_ms * sin(track_rad);
+
+		_gps_position->vel_m_s = velocity_ms;                            /**< GPS ground speed (m/s) */
+		_gps_position->vel_n_m_s = velocity_north;                       /**< GPS ground speed in m/s */
+		_gps_position->vel_e_m_s = velocity_east;                        /**< GPS ground speed in m/s */
+		_gps_position->vel_d_m_s = -vertic_vel;                      /**< GPS ground speed in m/s */
+		_gps_position->cog_rad =
+			track_rad;                              /**< Course over ground (NOT heading, but direction of movement) in rad, -PI..PI */
+		_gps_position->vel_ned_valid = true;                             /**< Flag to indicate if NED speed is valid */
+		_gps_position->c_variance_rad = 0.1;
+		_gps_position->timestamp_velocity = hrt_absolute_time();
+		return 1;
+
+	} else if ((memcmp(_rx_buffer + 3, "GST,", 3) == 0) && (uiCalcComma == 8)) {
+		/*
+		  Position error statistics
+		  An example of the GST message string is:
+
+		  $GPGST,172814.0,0.006,0.023,0.020,273.6,0.023,0.020,0.031*6A
+
+		  The Talker ID ($--) will vary depending on the satellite system used for the position solution:
+
+		  $GP - GPS only
+		  $GL - GLONASS only
+		  $GN - Combined
+		  GST message fields
+		  Field   Meaning
+		  0   Message ID $GPGST
+		  1   UTC of position fix
+		  2   RMS value of the pseudorange residuals; includes carrier phase residuals during periods of RTK (float) and RTK (fixed) processing
+		  3   Error ellipse semi-major axis 1 sigma error, in meters
+		  4   Error ellipse semi-minor axis 1 sigma error, in meters
+		  5   Error ellipse orientation, degrees from true north
+		  6   Latitude 1 sigma error, in meters
+		  7   Longitude 1 sigma error, in meters
+		  8   Height 1 sigma error, in meters
+		  9   The checksum data, always begins with *
+		*/
+		double ashtech_time __attribute__((unused)) = 0.0, lat_err = 0.0, lon_err = 0.0, alt_err = 0.0;
+		double min_err __attribute__((unused)) = 0.0, maj_err __attribute__((unused)) = 0.0, deg_from_north __attribute__((unused)) = 0.0, rms_err __attribute__((unused)) = 0.0;
+
+		if (bufptr && *(++bufptr) != ',') { ashtech_time = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { rms_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { maj_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { min_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { deg_from_north = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { lat_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { lon_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { alt_err = strtod(bufptr, &endp); bufptr = endp; }
+
+		_gps_position->eph = sqrt(lat_err * lat_err + lon_err * lon_err);
+		_gps_position->epv = alt_err;
+
+		_gps_position->s_variance_m_s = 0;
+		_gps_position->timestamp_variance = hrt_absolute_time();
+
+	} else if ((memcmp(_rx_buffer + 3, "GSV,", 3) == 0)) {
+		/*
+		  The GSV message string identifies the number of SVs in view, the PRN numbers, elevations, azimuths, and SNR values. An example of the GSV message string is:
+
+		  $GPGSV,4,1,13,02,02,213,,03,-3,000,,11,00,121,,14,13,172,05*67
+
+		  GSV message fields
+		  Field   Meaning
+		  0   Message ID $GPGSV
+		  1   Total number of messages of this type in this cycle
+		  2   Message number
+		  3   Total number of SVs visible
+		  4   SV PRN number
+		  5   Elevation, in degrees, 90 maximum
+		  6   Azimuth, degrees from True North, 000 through 359
+		  7   SNR, 00 through 99 dB (null when not tracking)
+		  8-11    Information about second SV, same format as fields 4 through 7
+		  12-15   Information about third SV, same format as fields 4 through 7
+		  16-19   Information about fourth SV, same format as fields 4 through 7
+		  20  The checksum data, always begins with *
+		*/
+		/*
+		 * currently process only gps, because do not know what
+		 * Global satellite ID I should use for non GPS sats
+		 */
+		bool bGPS = false;
+
+		if (memcmp(_rx_buffer, "$GP", 3) != 0) {
+			return 0;
+
+		} else {
+			bGPS = true;
+		}
+
+		int all_msg_num = 0, this_msg_num = 0, tot_sv_visible = 0;
+		struct gsv_sat {
+			int svid;
+			int elevation;
+			int azimuth;
+			int snr;
+		} sat[4];
+		memset(sat, 0, sizeof(sat));
+
+		if (bufptr && *(++bufptr) != ',') { all_msg_num = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { this_msg_num = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if (bufptr && *(++bufptr) != ',') { tot_sv_visible = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+		if ((this_msg_num < 1) || (this_msg_num > all_msg_num)) {
+			return 0;
+		}
+
+		if ((this_msg_num == 0) && (bGPS == true)) {
+			memset(_satellite_info->svid,     0, sizeof(_satellite_info->svid));
+			memset(_satellite_info->used,     0, sizeof(_satellite_info->used));
+			memset(_satellite_info->snr,      0, sizeof(_satellite_info->snr));
+			memset(_satellite_info->elevation, 0, sizeof(_satellite_info->elevation));
+			memset(_satellite_info->azimuth,  0, sizeof(_satellite_info->azimuth));
+		}
+
+		int end = 4;
+
+		if (this_msg_num == all_msg_num) {
+			end =  tot_sv_visible - (this_msg_num - 1) * 4;
+			_gps_position->satellites_used = tot_sv_visible;
+			_satellite_info->count = SAT_INFO_MAX_SATELLITES;
+			_satellite_info->timestamp = hrt_absolute_time();
+		}
+
+		for (int y = 0 ; y < end ; y++) {
+			if (bufptr && *(++bufptr) != ',') { sat[y].svid = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+			if (bufptr && *(++bufptr) != ',') { sat[y].elevation = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+			if (bufptr && *(++bufptr) != ',') { sat[y].azimuth = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+			if (bufptr && *(++bufptr) != ',') { sat[y].snr = strtol(bufptr, &endp, 10); bufptr = endp; }
+
+			_satellite_info->svid[y + (this_msg_num - 1) * 4]      = sat[y].svid;
+			_satellite_info->used[y + (this_msg_num - 1) * 4]      = ((sat[y].snr > 0) ? true : false);
+			_satellite_info->snr[y + (this_msg_num - 1) * 4]       = sat[y].snr;
+			_satellite_info->elevation[y + (this_msg_num - 1) * 4] = sat[y].elevation;
+			_satellite_info->azimuth[y + (this_msg_num - 1) * 4]   = sat[y].azimuth;
+		}
+	}
+
+	return 0;
+}
+
+
+int ASHTECH::receive(unsigned timeout)
+{
+	{
+		/* poll descriptor */
+		pollfd fds[1];
+		fds[0].fd = _fd;
+		fds[0].events = POLLIN;
+
+		uint8_t buf[32];
+
+		/* timeout additional to poll */
+		uint64_t time_started = hrt_absolute_time();
+
+		int j = 0;
+		ssize_t count = 0;
+
+		while (true) {
+
+			/* pass received bytes to the packet decoder */
+			while (j < count) {
+				int l = 0;
+
+				if ((l = 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(l) > 0) {
+						return 1;
+					}
+				}
+
+				/* in case we keep trying but only get crap from GPS */
+				if (time_started + timeout * 1000 * 2 < hrt_absolute_time()) {
+					return -1;
+				}
+
+				j++;
+			}
+
+			/* everything is read */
+			j = count = 0;
+
+			/* then poll for new data */
+			int ret = ::poll(fds, sizeof(fds) / sizeof(fds[0]), timeout * 2);
+
+			if (ret < 0) {
+				/* something went wrong when polling */
+				return -1;
+
+			} else if (ret == 0) {
+				/* Timeout */
+				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...
+					 */
+					count = ::read(_fd, buf, sizeof(buf));
+				}
+			}
+		}
+	}
+
+}
+#define HEXDIGIT_CHAR(d) ((char)((d) + (((d) < 0xA) ? '0' : 'A'-0xA)))
+
+int ASHTECH::parse_char(uint8_t b)
+{
+	int iRet = 0;
+
+	switch (_decode_state) {
+		/* First, look for sync1 */
+	case NME_DECODE_UNINIT:
+		if (b == '$') {
+			_decode_state = NME_DECODE_GOT_SYNC1;
+			_rx_buffer_bytes = 0;
+			_rx_buffer[_rx_buffer_bytes++] = b;
+		}
+
+		break;
+
+	case NME_DECODE_GOT_SYNC1:
+		if (b == '$') {
+			_decode_state = NME_DECODE_GOT_SYNC1;
+			_rx_buffer_bytes = 0;
+
+		} else if (b == '*') {
+			_decode_state = NME_DECODE_GOT_ASTERIKS;
+		}
+
+		if (_rx_buffer_bytes >= (sizeof(_rx_buffer) - 5)) {
+			_decode_state = NME_DECODE_UNINIT;
+			_rx_buffer_bytes = 0;
+
+		} else {
+			_rx_buffer[_rx_buffer_bytes++] = b;
+		}
+
+		break;
+
+	case NME_DECODE_GOT_ASTERIKS:
+		_rx_buffer[_rx_buffer_bytes++] = b;
+		_decode_state = NME_DECODE_GOT_FIRST_CS_BYTE;
+		break;
+
+	case NME_DECODE_GOT_FIRST_CS_BYTE:
+		_rx_buffer[_rx_buffer_bytes++] = b;
+		uint8_t checksum = 0;
+		uint8_t *buffer = _rx_buffer + 1;
+		uint8_t *bufend = _rx_buffer + _rx_buffer_bytes - 3;
+
+		for (; buffer < bufend; buffer++) { checksum ^= *buffer; }
+
+		if ((HEXDIGIT_CHAR(checksum >> 4) == *(_rx_buffer + _rx_buffer_bytes - 2)) &&
+		    (HEXDIGIT_CHAR(checksum & 0x0F) == *(_rx_buffer + _rx_buffer_bytes - 1))) {
+			iRet = _rx_buffer_bytes;
+		}
+
+		_decode_state = NME_DECODE_UNINIT;
+		_rx_buffer_bytes = 0;
+		break;
+	}
+
+	return iRet;
+}
+
+void ASHTECH::decode_init(void)
+{
+
+}
+
+/* 
+ * ashtech board configuration script 
+ */
+
+const char comm[] = "$PASHS,POP,20\r\n"\
+	      "$PASHS,NME,ZDA,B,ON,3\r\n"\
+	      "$PASHS,NME,GGA,B,OFF\r\n"\
+	      "$PASHS,NME,GST,B,ON,3\r\n"\
+	      "$PASHS,NME,POS,B,ON,0.05\r\n"\
+	      "$PASHS,NME,GSV,B,ON,3\r\n"\
+	      "$PASHS,SPD,A,8\r\n"\
+	      "$PASHS,SPD,B,9\r\n";
+
+int ASHTECH::configure(unsigned &baudrate)
+{
+	/* try different baudrates */
+	const unsigned baudrates_to_try[] = {9600, 38400, 19200, 57600, 115200};
+
+
+	for (int baud_i = 0; baud_i < sizeof(baudrates_to_try) / sizeof(baudrates_to_try[0]); baud_i++) {
+		baudrate = baudrates_to_try[baud_i];
+		set_baudrate(_fd, baudrate);
+		write(_fd, (uint8_t *)comm, sizeof(comm));
+	}
+
+	set_baudrate(_fd, 115200);
+	return 0;
+}
diff --git a/src/drivers/gps/ashtech.h b/src/drivers/gps/ashtech.h
new file mode 100644
index 000000000..6e65d0b2b
--- /dev/null
+++ b/src/drivers/gps/ashtech.h
@@ -0,0 +1,96 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013. All rights reserved.
+ *   Author: Boriskin Aleksey <a.d.boriskin@gmail.com>
+ *           Kistanov Alexander <akistanov@gramant.ru>
+ *
+ * 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 ASHTECH protocol definitions */
+
+#ifndef ASHTECH_H_
+#define ASHTECH_H_
+
+#include "gps_helper.h"
+
+#ifndef RECV_BUFFER_SIZE
+#define RECV_BUFFER_SIZE 512
+
+#define SAT_INFO_MAX_SATELLITES  20
+#endif
+
+
+class ASHTECH : public GPS_Helper
+{
+	enum ashtech_decode_state_t {
+		NME_DECODE_UNINIT,
+		NME_DECODE_GOT_SYNC1,
+		NME_DECODE_GOT_ASTERIKS,
+		NME_DECODE_GOT_FIRST_CS_BYTE
+	};
+
+	int                    _fd;
+	struct satellite_info_s *_satellite_info;
+	struct vehicle_gps_position_s *_gps_position;
+	int ashtechlog_fd;
+
+	ashtech_decode_state_t   _decode_state;
+	uint8_t               _rx_buffer[RECV_BUFFER_SIZE];
+	uint16_t              _rx_buffer_bytes;
+	bool                  _parse_error; 		/** parse error flag */
+	char                 *_parse_pos; 		/** parse position */
+
+	bool	_gsv_in_progress;			/**< Indicates that gsv data parsing is in progress */
+	/* int     _satellites_count; 			/**< Number of satellites info parsed. */
+	uint8_t count;					/**< Number of satellites in satellite info */
+	uint8_t svid[SAT_INFO_MAX_SATELLITES]; 		/**< Space vehicle ID [1..255], see scheme below  */
+	uint8_t used[SAT_INFO_MAX_SATELLITES];		/**< 0: Satellite not used, 1: used for navigation */
+	uint8_t elevation[SAT_INFO_MAX_SATELLITES];	/**< Elevation (0: right on top of receiver, 90: on the horizon) of satellite */
+	uint8_t azimuth[SAT_INFO_MAX_SATELLITES];	/**< Direction of satellite, 0: 0 deg, 255: 360 deg. */
+	uint8_t snr[SAT_INFO_MAX_SATELLITES];		/**< dBHz, Signal to noise ratio of satellite C/N0, range 0..99, zero when not tracking this satellite. */
+
+public:
+	ASHTECH(const int &fd, struct vehicle_gps_position_s *gps_position, struct satellite_info_s *satellite_info);
+	~ASHTECH();
+	int             receive(unsigned timeout);
+	int             configure(unsigned &baudrate);
+	void            decode_init(void);
+	int             handle_message(int len);
+	int             parse_char(uint8_t b);
+	/** Read int ASHTECH parameter */
+	int32_t         read_int();
+	/** Read float ASHTECH parameter */
+	double       read_float();
+	/** Read char ASHTECH parameter */
+	char            read_char();
+
+};
+
+#endif /* ASHTECH_H_ */
diff --git a/src/drivers/gps/gps.cpp b/src/drivers/gps/gps.cpp
index 34dd63086..5fb4b9ff8 100644
--- a/src/drivers/gps/gps.cpp
+++ b/src/drivers/gps/gps.cpp
@@ -69,6 +69,7 @@
 
 #include "ubx.h"
 #include "mtk.h"
+#include "ashtech.h"
 
 
 #define TIMEOUT_5HZ 500
@@ -341,6 +342,10 @@ GPS::task_main()
 				_Helper = new MTK(_serial_fd, &_report_gps_pos);
 				break;
 
+			case GPS_DRIVER_MODE_ASHTECH:
+				_Helper = new ASHTECH(_serial_fd, &_report_gps_pos, _p_report_sat_info);
+				break;
+
 			default:
 				break;
 			}
@@ -402,6 +407,10 @@ GPS::task_main()
 							mode_str = "MTK";
 							break;
 
+						case GPS_DRIVER_MODE_ASHTECH:
+							mode_str = "ASHTECH";
+							break;
+
 						default:
 							break;
 						}
@@ -429,6 +438,10 @@ GPS::task_main()
 				break;
 
 			case GPS_DRIVER_MODE_MTK:
+				_mode = GPS_DRIVER_MODE_ASHTECH;
+				break;
+
+			case GPS_DRIVER_MODE_ASHTECH:
 				_mode = GPS_DRIVER_MODE_UBX;
 				break;
 
@@ -475,6 +488,10 @@ GPS::print_info()
 		warnx("protocol: MTK");
 		break;
 
+	case GPS_DRIVER_MODE_ASHTECH:
+		warnx("protocol: ASHTECH");
+		break;
+
 	default:
 		break;
 	}
diff --git a/src/drivers/gps/module.mk b/src/drivers/gps/module.mk
index b00818424..4f99b0d3b 100644
--- a/src/drivers/gps/module.mk
+++ b/src/drivers/gps/module.mk
@@ -40,6 +40,7 @@ MODULE_COMMAND	= gps
 SRCS		= gps.cpp \
 		  gps_helper.cpp \
 		  mtk.cpp \
+		  ashtech.cpp \
 		  ubx.cpp
 
 MODULE_STACKSIZE = 1200
diff --git a/src/modules/uORB/topics/vehicle_gps_position.h b/src/modules/uORB/topics/vehicle_gps_position.h
index 80d65cd69..31e616f4f 100644
--- a/src/modules/uORB/topics/vehicle_gps_position.h
+++ b/src/modules/uORB/topics/vehicle_gps_position.h
@@ -62,7 +62,7 @@ struct vehicle_gps_position_s {
 	uint64_t timestamp_variance;
 	float s_variance_m_s;				/**< speed accuracy estimate m/s */
 	float c_variance_rad;				/**< course accuracy estimate rad */
-	uint8_t fix_type; 				/**< 0-1: no fix, 2: 2D fix, 3: 3D fix. Some applications will not use the value of this field unless it is at least two, so always correctly fill in the fix.   */
+	uint8_t fix_type; 				/**< 0-1: no fix, 2: 2D fix, 3: 3D fix, 4: RTCM code differential, 5: Real-Time Kinematic, float, 6: Real-Time Kinematic, fixed, 8: Extrapolated. Some applications will not use the value of this field unless it is at least two, so always correctly fill in the fix.   */
 
 	float eph;					/**< GPS HDOP horizontal dilution of position in m */
 	float epv;					/**< GPS VDOP horizontal dilution of position in m */