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|
#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 = static_cast<int>(ashtech_time / 10000);
int ashtech_minute = static_cast<int>((ashtech_time - ashtech_hour * 10000) / 100);
double ashtech_sec = static_cast<float>(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);
if (epoch > GPS_EPOCH_SECS) {
uint64_t usecs = static_cast<uint64_t>((ashtech_sec - static_cast<uint64_t>(ashtech_sec))) * 1000000;
// FMUv2+ boards have a hardware RTC, but GPS helps us to configure it
// and control its drift. Since we rely on the HRT for our monotonic
// clock, updating it from time to time is safe.
timespec ts;
ts.tv_sec = epoch;
ts.tv_nsec = usecs * 1000;
if (clock_settime(CLOCK_REALTIME, &ts)) {
warn("failed setting clock");
}
_gps_position->time_utc_usec = static_cast<uint64_t>(epoch) * 1000000ULL;
_gps_position->time_utc_usec += usecs;
} else {
_gps_position->time_utc_usec = 0;
}
_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;
}
/* convert from degrees, minutes and seconds to degrees * 1e7 */
_gps_position->lat = static_cast<int>((int(lat * 0.01) + (lat * 0.01 - int(lat * 0.01)) * 100.0 / 60.0) * 10000000);
_gps_position->lon = static_cast<int>((int(lon * 0.01) + (lon * 0.01 - int(lon * 0.01)) * 100.0 / 60.0) * 10000000);
_gps_position->alt = static_cast<int>(alt * 1000);
_rate_count_lat_lon++;
if (fix_quality <= 0) {
_gps_position->fix_type = 0;
} else {
/*
* in this NMEA message float integers (value 5) mode has higher value than fixed integers (value 4), whereas it provides lower quality,
* and since value 3 is not being used, I "moved" value 5 to 3 to add it to _gps_position->fix_type
*/
if (fix_quality == 5) { fix_quality = 3; }
/*
* fix quality 1 means just a normal 3D fix, so I'm subtracting 1 here. This way we'll have 3 for auto, 4 for DGPS, 5 for floats, 6 for fixed.
*/
_gps_position->fix_type = 3 + fix_quality - 1;
}
_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 = 0.1f;
_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);
/*
* Ashtech would return empty space as coordinate (lat, lon or alt) if it doesn't have a fix yet
*/
int coordinatesFound = 0;
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) != ',') {
/*
* if a coordinate is skipped (i.e. no fix), it either won't get into this block (two commas in a row)
* or strtod won't find anything and endp will point exactly where bufptr is. The same is for lon and alt.
*/
lat = strtod(bufptr, &endp);
if (bufptr != endp) {coordinatesFound++;}
bufptr = endp;
}
if (bufptr && *(++bufptr) != ',') { ns = *(bufptr++); }
if (bufptr && *(++bufptr) != ',') {
lon = strtod(bufptr, &endp);
if (bufptr != endp) {coordinatesFound++;}
bufptr = endp;
}
if (bufptr && *(++bufptr) != ',') { ew = *(bufptr++); }
if (bufptr && *(++bufptr) != ',') {
alt = strtod(bufptr, &endp);
if (bufptr != endp) {coordinatesFound++;}
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 = static_cast<int>((int(lat * 0.01) + (lat * 0.01 - int(lat * 0.01)) * 100.0 / 60.0) * 10000000);
_gps_position->lon = static_cast<int>((int(lon * 0.01) + (lon * 0.01 - int(lon * 0.01)) * 100.0 / 60.0) * 10000000);
_gps_position->alt = static_cast<int>(alt * 1000);
_rate_count_lat_lon++;
if (coordinatesFound < 3) {
_gps_position->fix_type = 0;
} else {
_gps_position->fix_type = 3 + fix_quality;
}
_gps_position->timestamp_position = hrt_absolute_time();
float track_rad = static_cast<float>(track_true) * M_PI_F / 180.0f;
float velocity_ms = static_cast<float>(ground_speed) / 1.9438445f; /** knots to m/s */
float velocity_north = static_cast<float>(velocity_ms) * cosf(track_rad);
float velocity_east = static_cast<float>(velocity_ms) * sinf(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 = static_cast<float>(-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 = 0.1f;
_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 = sqrtf(static_cast<float>(lat_err) * static_cast<float>(lat_err)
+ static_cast<float>(lon_err) * static_cast<float>(lon_err));
_gps_position->epv = static_cast<float>(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 bytes_count = 0;
while (true) {
/* pass received bytes to the packet decoder */
while (j < bytes_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 = bytes_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...
*/
bytes_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 (unsigned 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, comm, sizeof(comm));
}
set_baudrate(_fd, 115200);
return 0;
}
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