/*
- Read files containing selected NMEA 0183 sentences.
- Based on information by Eino Uikkanenj
+ Read files containing selected NMEA 0183 sentences.
+ Based on information by Eino Uikkanenj
- Copyright (C) 2004 Robert Lipe, robertlipe@usa.net
+ Copyright (C) 2004-2005 Robert Lipe, robertlipe@usa.net
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
*/
' 10 300504 Date 30/05-2004
' 11 Empty field Magnetic variation
- GSA - GPS DOP and active satellites
- $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
- A Auto selection of 2D or 3D fix (M = manual)
- 3 3D fix
- 04,05... PRNs of satellites used for fix (space for 12)
- 2.5 PDOP (dilution of precision)
- 1.3 Horizontal dilution of precision (HDOP)
- 2.1 Vertical dilution of precision (VDOP)
- DOP is an indication of the effect of satellite geometry on
- the accuracy of the fix.
-
- VTG - Track made good and ground speed
- $GPVTG,054.7,T,034.4,M,005.5,N,010.2,K
- 054.7,T True track made good
- 034.4,M Magnetic track made good
- 005.5,N Ground speed, knots
- 010.2,K Ground speed, Kilometers per hour
-
- WPL - waypoint location
- $GPWPL,4917.16,N,12310.64,W,003*65
- 4917.16,N Latitude of waypoint
- 12310.64,W Longitude of waypoint
- 003 Waypoint ID
- When a route is active, this sentence is sent once for each
- waypoint in the route, in sequence. When all waypoints have
- been reported, GPR00 is sent in the next data set. In any
- group of sentences, only one WPL sentence, or an R00
- sentence, will be sent.
+ GSA - GPS DOP and active satellites
+ $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
+ A Auto selection of 2D or 3D fix (M = manual)
+ 3 3D fix
+ 04,05... PRNs of satellites used for fix (space for 12)
+ 2.5 PDOP (dilution of precision)
+ 1.3 Horizontal dilution of precision (HDOP)
+ 2.1 Vertical dilution of precision (VDOP)
+ DOP is an indication of the effect of satellite geometry on
+ the accuracy of the fix.
+
+ VTG - Track made good and ground speed
+ $GPVTG,054.7,T,034.4,M,005.5,N,010.2,K
+ 054.7,T True track made good
+ 034.4,M Magnetic track made good
+ 005.5,N Ground speed, knots
+ 010.2,K Ground speed, Kilometers per hour
+
+ WPL - waypoint location
+ $GPWPL,4917.16,N,12310.64,W,003*65
+ 4917.16,N Latitude of waypoint
+ 12310.64,W Longitude of waypoint
+ 003 Waypoint ID
+ When a route is active, this sentence is sent once for each
+ waypoint in the route, in sequence. When all waypoints have
+ been reported, GPR00 is sent in the next data set. In any
+ group of sentences, only one WPL sentence, or an R00
+ sentence, will be sent.
' The optional checksum field consists of a "*" and two hex digits repre-
* same position fix. If we see a single GGA, start ignoring GLL's and RMC's.
* GLL's will also be ignored if RMC's are found and GGA's not found.
*/
+
+/*
+Zmarties notes:
+
+In practice, all fields of the NMEA sentences should be treated as optional -
+if the data is not available, then the field can be omitted (hence leading
+to the output of two consecutive commas).
+
+An NMEA recording can start anywhere in the stream of data. It is therefore
+necessary to discard sentences until sufficient data has been processed to
+have all the necessary data to construct a waypoint. In practice, this means
+discarding data until we have had the first sentence that provides the date.
+(We could scan forwards in the stream of data to find the first date, and
+then back apply it to all previous sentences, but that is probably more
+complexity that is necessary - the lost of one waypoint at the start of the
+stream can normally be tolerated.)
+
+If a sentence is received without a checksum, but previous sentences have
+had checksums, it is best to discard that sentence. In practice, the only
+time I have seen this is when the recording stops suddenly, where the last
+sentence is truncated - and missing part of the line, including the checksum.
+*/
typedef enum {
gp_unknown = 0,
static route_head *trk_head;
static short_handle mkshort_handle;
static preferred_posn_type posn_type;
-static time_t creation_time;
-static waypoint * curr_waypt =NULL;
+static struct tm tm;
+static waypoint * curr_waypt = NULL;
+
+static int had_date = 0;
#define MYNAME "nmea"
char lngdir, latdir;
int hms;
char valid;
- struct tm tm;
waypoint *waypt;
if (trk_head == NULL) {
track_add_head(trk_head);
}
- memset(&tm, 0, sizeof(tm));
-
sscanf(ibuf,"$GPGLL,%lf,%c,%lf,%c,%d,%c,",
&latdeg,&latdir,
&lngdeg,&lngdir,
waypt = waypt_new();
- waypt->creation_time = creation_time;
+ waypt->creation_time = mkgmtime(&tm);
if (latdir == 'S') latdeg = -latdeg;
waypt->latitude = ddmm2degrees(latdeg);
double latdeg, lngdeg;
char lngdir, latdir;
double hms;
- struct tm tm;
double alt;
int fix;
int nsats;
track_add_head(trk_head);
}
- memset(&tm, 0, sizeof(tm));
-
sscanf(ibuf,"$GPGGA,%lf,%lf,%c,%lf,%c,%d,%d,%lf,%lf,%c",
&hms, &latdeg,&latdir,
&lngdeg,&lngdir,
waypt = waypt_new();
- waypt->creation_time = creation_time;
+ waypt->creation_time = mkgmtime(&tm);
if (latdir == 'S') latdeg = -latdeg;
waypt->latitude = ddmm2degrees(latdeg);
curr_waypt = waypt;
route_add_wpt(trk_head, waypt);
-
-
}
static void
double hms;
char fix;
unsigned int dmy;
- struct tm tm;
double speed,course;
waypoint *waypt;
track_add_head(trk_head);
}
- memset(&tm, 0, sizeof(tm));
-
sscanf(ibuf,"$GPRMC,%lf,%c,%lf,%c,%lf,%c,%lf,%lf,%u",
&hms, &fix, &latdeg, &latdir,
&lngdeg, &lngdir,
&speed, &course, &dmy);
+
+ if (fix != 'A') {
+ /* ignore this fix - it is invalid */
+ return;
+ }
tm.tm_sec = (long) hms % 100;
hms = hms / 100;
tm.tm_mon = dmy % 100 - 1;
dmy = dmy / 100;
tm.tm_mday = dmy;
- creation_time = mkgmtime(&tm);
+
+ had_date = 1;
if (posn_type == gpgga) {
/* capture useful data update and exit */
waypt->course = course;
- waypt->creation_time = creation_time;
+ waypt->creation_time = mkgmtime(&tm);
if (latdir == 'S') latdeg = -latdeg;
waypt->latitude = ddmm2degrees(latdeg);
{
double hms;
int dd, mm, yy, lclhrs, lclmins;
- struct tm tm;
- memset(&tm, 0, sizeof(tm));
sscanf(ibuf,"$GPZDA,%lf,%d,%d,%d,%d,%d",
&hms, &dd, &mm, &yy, &lclhrs, &lclmins);
tm.tm_sec = (int) hms % 100;
tm.tm_mday = dd;
tm.tm_mon = mm - 1;
tm.tm_year = yy - 1900;
- creation_time = mkgmtime(&tm);
+
+ had_date = 1;
}
static void
char cn;
double speed_k;
char ck;
-
+
sscanf(ibuf,"$GPVTG,%f,%c,%f,%c,%lf,%c,%lf,%c",
&course,&ct,&magcourse,&cm,&speed_n,&cn,&speed_k,&ck);
char ibuf[1024];
char *ck;
int ckval, ckcmp;
- struct tm tm;
+ int had_checksum = 0;
- creation_time = mkgmtime(&tm) + current_time();
+ had_date = 0;
curr_waypt = NULL;
while (fgets(ibuf, sizeof(ibuf), file_in)) {
- ck = strrchr(ibuf, '*');
+ char *tbuf = ibuf;
+
+ ck = strrchr(tbuf, '*');
if (ck != NULL) {
*ck = '\0';
- ckval = nmea_cksum(&ibuf[1]);
+ ckval = nmea_cksum(&tbuf[1]);
*ck = '*';
ck++;
sscanf(ck, "%2X", &ckcmp);
if (ckval != ckcmp) {
#if 0
printf("ckval %X, %X, %s\n", ckval, ckcmp, ck);
- printf("NMEA %s\n", ibuf);
+ printf("NMEA %s\n", tbuf);
#endif
continue;
}
+
+ had_checksum = 1;
}
- if (0 == strncmp(ibuf, "$GPWPL,", 7)) {
- gpwpl_parse(ibuf);
+ else if (had_checksum) {
+ /* we have had a checksum on all previous sentences, but not on this
+ one, which probably indicates this line is truncated */
+ had_checksum = 0;
+ continue;
+ }
+
+ /* Only GPRMC and GPZDA sentences have dates in them, so we discard all
+ sentences until we see one of those
+ */
+ if (!had_date &&
+ (0 != strncmp(tbuf, "$GPRMC,", 7)) &&
+ (0 != strncmp(tbuf, "$GPZDA,", 7))) {
+ continue;
+ }
+
+ /* @@@ zmarties: The parse routines all assume all fields are present, but
+ the NMEA format allows any field to be missed out if there is no data
+ for that field. Rather than change all the parse routines, we first
+ substitute a default value of zero for any missing field.
+ */
+ if (strstr(tbuf, ",,"))
+ {
+ tbuf = gstrsub(tbuf, ",,", ",0,");
+ }
+
+ if (0 == strncmp(tbuf, "$GPWPL,", 7)) {
+ gpwpl_parse(tbuf);
} else
- if (0 == strncmp(ibuf, "$GPGGA,", 7)) {
+ if (0 == strncmp(tbuf, "$GPGGA,", 7)) {
posn_type = gpgga;
- gpgga_parse(ibuf);
+ gpgga_parse(tbuf);
} else
- if (0 == strncmp(ibuf, "$GPRMC,", 7)) {
+ if (0 == strncmp(tbuf, "$GPRMC,", 7)) {
if (posn_type != gpgga) {
posn_type = gprmc;
}
/*
- * Allways call gprmc_parse() because like GPZDA
+ * Always call gprmc_parse() because like GPZDA
* it contains the full date.
*/
- gprmc_parse(ibuf);
+ gprmc_parse(tbuf);
} else
- if (0 == strncmp(ibuf, "$GPGLL,", 7)) {
+ if (0 == strncmp(tbuf, "$GPGLL,", 7)) {
if ((posn_type != gpgga) && (posn_type != gprmc)) {
- gpgll_parse(ibuf);
+ gpgll_parse(tbuf);
}
} else
- if (0 == strncmp(ibuf, "$GPZDA,",7)) {
- gpzda_parse(ibuf);
+ if (0 == strncmp(tbuf, "$GPZDA,",7)) {
+ gpzda_parse(tbuf);
} else
- if (0 == strncmp(ibuf, "$GPVTG,",7)) {
- gpvtg_parse(ibuf); /* speed and course */
+ if (0 == strncmp(tbuf, "$GPVTG,",7)) {
+ gpvtg_parse(tbuf); /* speed and course */
} else
- if (0 == strncmp(ibuf, "$GPGSA,",7)) {
- gpgsa_parse(ibuf); /* GPS fix */
+ if (0 == strncmp(tbuf, "$GPGSA,",7)) {
+ gpgsa_parse(tbuf); /* GPS fix */
}
+
+ if (tbuf != ibuf) {
+ /* clear up the dynamic buffer we used because substition was required */
+ xfree(tbuf);
+ }
}
}
projects / gpsbabel.git / commitdiff