2 * refclock_nmea.c - clock driver for an NMEA GPS CLOCK
3 * Michael Petry Jun 20, 1994
4 * based on refclock_heathn.c
10 #if defined(SYS_WINNT)
12 #define close closesocket
15 #if defined(REFCLOCK) && defined(CLOCK_NMEA)
22 #include "ntp_unixtime.h"
23 #include "ntp_refclock.h"
24 #include "ntp_stdlib.h"
27 # include "ppsapi_timepps.h"
28 #endif /* HAVE_PPSAPI */
31 * This driver supports the NMEA GPS Receiver with
33 * Protype was refclock_trak.c, Thanks a lot.
35 * The receiver used spits out the NMEA sentences for boat navigation.
36 * And you thought it was an information superhighway. Try a raging river
37 * filled with rapids and whirlpools that rip away your data and warp time.
39 * If HAVE_PPSAPI is defined code to use the PPSAPI will be compiled in.
40 * On startup if initialization of the PPSAPI fails, it will fall back
41 * to the "normal" timestamps.
43 * The PPSAPI part of the driver understands fudge flag2 and flag3. If
44 * flag2 is set, it will use the clear edge of the pulse. If flag3 is
45 * set, kernel hardpps is enabled.
47 * GPS sentences other than RMC (the default) may be enabled by setting
48 * the relevent bits of 'mode' in the server configuration line
49 * server 127.127.20.x mode X
51 * bit 0 - enables RMC (1)
52 * bit 1 - enables GGA (2)
53 * bit 2 - enables GLL (4)
54 * multiple sentences may be selected
61 # define DEVICE "COM%d:" /* COM 1 - 3 supported */
63 # define DEVICE "/dev/gps%d" /* name of radio device */
65 #define SPEED232 B4800 /* uart speed (4800 bps) */
66 #define PRECISION (-9) /* precision assumed (about 2 ms) */
67 #define PPS_PRECISION (-20) /* precision assumed (about 1 us) */
68 #define REFID "GPS\0" /* reference id */
69 #define DESCRIPTION "NMEA GPS Clock" /* who we are */
70 #define NANOSECOND 1000000000 /* one second (ns) */
71 #define RANGEGATE 500000 /* range gate (ns) */
73 #define LENNMEA 75 /* min timecode length */
76 * Tables to compute the ddd of year form icky dd/mm timecode. Viva la
79 static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
80 static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
83 * Unit control structure
86 int pollcnt; /* poll message counter */
87 int polled; /* Hand in a sample? */
88 l_fp tstamp; /* timestamp of last poll */
90 struct timespec ts; /* last timestamp */
91 pps_params_t pps_params; /* pps parameters */
92 pps_info_t pps_info; /* last pps data */
93 pps_handle_t handle; /* pps handlebars */
94 #endif /* HAVE_PPSAPI */
100 static int nmea_start P((int, struct peer *));
101 static void nmea_shutdown P((int, struct peer *));
103 static void nmea_control P((int, struct refclockstat *, struct
104 refclockstat *, struct peer *));
105 static int nmea_ppsapi P((struct peer *, int, int));
106 static int nmea_pps P((struct nmeaunit *, l_fp *));
107 #endif /* HAVE_PPSAPI */
108 static void nmea_receive P((struct recvbuf *));
109 static void nmea_poll P((int, struct peer *));
110 static void gps_send P((int, const char *, struct peer *));
111 static char *field_parse P((char *, int));
116 struct refclock refclock_nmea = {
117 nmea_start, /* start up driver */
118 nmea_shutdown, /* shut down driver */
119 nmea_poll, /* transmit poll message */
121 nmea_control, /* fudge control */
123 noentry, /* fudge control */
124 #endif /* HAVE_PPSAPI */
125 noentry, /* initialize driver */
126 noentry, /* buginfo */
127 NOFLAGS /* not used */
131 * nmea_start - open the GPS devices and initialize data for processing
139 register struct nmeaunit *up;
140 struct refclockproc *pp;
145 * Open serial port. Use CLK line discipline, if available.
147 (void)sprintf(device, DEVICE, unit);
149 fd = refclock_open(device, SPEED232, LDISC_CLK);
152 /* nmead support added by Jon Miner (cp_n18@yahoo.com)
154 * See http://home.hiwaay.net/~taylorc/gps/nmea-server/
155 * for information about nmead
157 * To use this, you need to create a link from /dev/gpsX to
158 * the server:port where nmead is running. Something like this:
160 * ln -s server:port /dev/gps1
168 struct sockaddr_in so_addr;
170 if ((len = readlink(device,buffer,sizeof(buffer))) == -1)
174 if ((nmea_host = strtok(buffer,":")) == NULL)
177 nmea_port = atoi(strtok(NULL,":"));
179 if ((he = gethostbyname(nmea_host)) == NULL)
181 if ((p = getprotobyname("ip")) == NULL)
183 so_addr.sin_family = AF_INET;
184 so_addr.sin_port = htons(nmea_port);
185 so_addr.sin_addr = *((struct in_addr *) he->h_addr);
187 if ((fd = socket(PF_INET,SOCK_STREAM,p->p_proto)) == -1)
189 if (connect(fd,(struct sockaddr *)&so_addr,SOCKLEN(&so_addr)) == -1) {
199 * Allocate and initialize unit structure
201 up = (struct nmeaunit *)emalloc(sizeof(struct nmeaunit));
206 memset((char *)up, 0, sizeof(struct nmeaunit));
208 pp->io.clock_recv = nmea_receive;
209 pp->io.srcclock = (caddr_t)peer;
212 if (!io_addclock(&pp->io)) {
217 pp->unitptr = (caddr_t)up;
220 * Initialize miscellaneous variables
222 peer->precision = PRECISION;
223 pp->clockdesc = DESCRIPTION;
224 memcpy((char *)&pp->refid, REFID, 4);
226 gps_send(pp->io.fd,"$PMOTG,RMC,0000*1D\r\n", peer);
230 * Start the PPSAPI interface if it is there. Default to use
231 * the assert edge and do not enable the kernel hardpps.
233 if (time_pps_create(fd, &up->handle) < 0) {
236 "refclock_nmea: time_pps_create failed: %m");
239 return(nmea_ppsapi(peer, 0, 0));
242 #endif /* HAVE_PPSAPI */
246 * nmea_shutdown - shut down a GPS clock
254 register struct nmeaunit *up;
255 struct refclockproc *pp;
258 up = (struct nmeaunit *)pp->unitptr;
261 time_pps_destroy(up->handle);
262 #endif /* HAVE_PPSAPI */
263 io_closeclock(&pp->io);
269 * nmea_control - fudge control
273 int unit, /* unit (not used */
274 struct refclockstat *in, /* input parameters (not uded) */
275 struct refclockstat *out, /* output parameters (not used) */
276 struct peer *peer /* peer structure pointer */
279 struct refclockproc *pp;
282 nmea_ppsapi(peer, pp->sloppyclockflag & CLK_FLAG2,
283 pp->sloppyclockflag & CLK_FLAG3);
292 struct peer *peer, /* peer structure pointer */
293 int enb_clear, /* clear enable */
294 int enb_hardpps /* hardpps enable */
297 struct refclockproc *pp;
302 up = (struct nmeaunit *)pp->unitptr;
303 if (time_pps_getcap(up->handle, &capability) < 0) {
305 "refclock_nmea: time_pps_getcap failed: %m");
308 memset(&up->pps_params, 0, sizeof(pps_params_t));
310 up->pps_params.mode = capability & PPS_CAPTURECLEAR;
312 up->pps_params.mode = capability & PPS_CAPTUREASSERT;
313 if (!up->pps_params.mode) {
315 "refclock_nmea: invalid capture edge %d",
319 up->pps_params.mode |= PPS_TSFMT_TSPEC;
320 if (time_pps_setparams(up->handle, &up->pps_params) < 0) {
322 "refclock_nmea: time_pps_setparams failed: %m");
326 if (time_pps_kcbind(up->handle, PPS_KC_HARDPPS,
327 up->pps_params.mode & ~PPS_TSFMT_TSPEC,
328 PPS_TSFMT_TSPEC) < 0) {
330 "refclock_nmea: time_pps_kcbind failed: %m");
335 peer->precision = PPS_PRECISION;
339 time_pps_getparams(up->handle, &up->pps_params);
341 "refclock_ppsapi: capability 0x%x version %d mode 0x%x kern %d\n",
342 capability, up->pps_params.api_version,
343 up->pps_params.mode, enb_hardpps);
351 * Get PPSAPI timestamps.
353 * Return 0 on failure and 1 on success.
362 struct timespec timeout, ts;
367 * Convert the timespec nanoseconds field to ntp l_fp units.
373 memcpy(&pps_info, &up->pps_info, sizeof(pps_info_t));
374 if (time_pps_fetch(up->handle, PPS_TSFMT_TSPEC, &up->pps_info,
377 if (up->pps_params.mode & PPS_CAPTUREASSERT) {
378 if (pps_info.assert_sequence ==
379 up->pps_info.assert_sequence)
381 ts = up->pps_info.assert_timestamp;
382 } else if (up->pps_params.mode & PPS_CAPTURECLEAR) {
383 if (pps_info.clear_sequence ==
384 up->pps_info.clear_sequence)
386 ts = up->pps_info.clear_timestamp;
390 if ((up->ts.tv_sec == ts.tv_sec) && (up->ts.tv_nsec == ts.tv_nsec))
394 tstmp.l_ui = ts.tv_sec + JAN_1970;
395 dtemp = ts.tv_nsec * FRAC / 1e9;
396 tstmp.l_uf = (u_int32)dtemp;
400 #endif /* HAVE_PPSAPI */
403 * nmea_receive - receive data from the serial interface
407 struct recvbuf *rbufp
410 register struct nmeaunit *up;
411 struct refclockproc *pp;
417 /* Use these variables to hold data until we decide its worth keeping */
418 char rd_lastcode[BMAX];
423 * Initialize pointers and read the timecode and timestamp
425 peer = (struct peer *)rbufp->recv_srcclock;
427 up = (struct nmeaunit *)pp->unitptr;
428 rd_lencode = (u_short)refclock_gtlin(rbufp, rd_lastcode, BMAX, &rd_tmp);
431 * There is a case that a <CR><LF> gives back a "blank" line
438 printf("nmea: gpsread %d %s\n", rd_lencode,
443 * We check the timecode format and decode its contents. The
444 * we only care about a few of them. The most important being
446 * $GPRMC,hhmmss,a,fddmm.xx,n,dddmmm.xx,w,zz.z,yyy.,ddmmyy,dd,v*CC
447 * For Magellan (ColorTrak) GLL probably datum (order of sentences)
448 * also mode (0,1,2,3) select sentence ANY/ALL, RMC, GGA, GLL
449 * $GPGLL,3513.8385,S,14900.7851,E,232420.594,A*21
450 * $GPGGA,232420.59,3513.8385,S,14900.7851,E,1,05,3.4,00519,M,,,,*3F
452 * $GPRMC,232418.19,A,3513.8386,S,14900.7853,E,00.0,000.0,121199,12.,E*77
464 if(strncmp(cp,"$GPRMC",6)==0) {
467 else if(strncmp(cp,"$GPGGA",6)==0) {
470 else if(strncmp(cp,"$GPGLL",6)==0) {
473 else if(strncmp(cp,"$GPXXX",6)==0) {
480 /* See if I want to process this message type */
481 if ( ((peer->ttl == 0) && (cmdtype != GPRMC))
482 || ((peer->ttl != 0) && !(cmdtype & peer->ttl)) )
485 pp->lencode = rd_lencode;
486 strcpy(pp->a_lastcode,rd_lastcode);
489 pp->lastrec = up->tstamp = rd_tmp;
494 printf("nmea: timecode %d %s\n", pp->lencode,
499 /* Grab field depending on clock string type */
503 * Test for synchronization. Check for quality byte.
505 dp = field_parse(cp,2);
507 pp->leap = LEAP_NOTINSYNC;
509 pp->leap = LEAP_NOWARNING;
511 /* Now point at the time field */
512 dp = field_parse(cp,1);
518 * Test for synchronization. Check for quality byte.
520 dp = field_parse(cp,6);
522 pp->leap = LEAP_NOTINSYNC;
524 pp->leap = LEAP_NOWARNING;
526 /* Now point at the time field */
527 dp = field_parse(cp,1);
533 * Test for synchronization. Check for quality byte.
535 dp = field_parse(cp,6);
537 pp->leap = LEAP_NOTINSYNC;
539 pp->leap = LEAP_NOWARNING;
541 /* Now point at the time field */
542 dp = field_parse(cp,5);
554 * Check time code format of NMEA
557 if( !isdigit((int)dp[0]) ||
558 !isdigit((int)dp[1]) ||
559 !isdigit((int)dp[2]) ||
560 !isdigit((int)dp[3]) ||
561 !isdigit((int)dp[4]) ||
564 refclock_report(peer, CEVNT_BADREPLY);
570 * Convert time and check values.
572 pp->hour = ((dp[0] - '0') * 10) + dp[1] - '0';
573 pp->minute = ((dp[2] - '0') * 10) + dp[3] - '0';
574 pp->second = ((dp[4] - '0') * 10) + dp[5] - '0';
575 /* Default to 0 milliseconds, if decimal convert milliseconds in
576 one, two or three digits
580 if (isdigit((int)dp[7])) {
581 pp->nsec = (dp[7] - '0') * 100000000;
582 if (isdigit((int)dp[8])) {
583 pp->nsec += (dp[8] - '0') * 10000000;
584 if (isdigit((int)dp[9])) {
585 pp->nsec += (dp[9] - '0') * 1000000;
591 if (pp->hour > 23 || pp->minute > 59 || pp->second > 59
592 || pp->nsec > 1000000000) {
593 refclock_report(peer, CEVNT_BADTIME);
599 * Convert date and check values.
601 if (cmdtype==GPRMC) {
602 dp = field_parse(cp,9);
604 day = (day * 10) + dp[1] - '0';
606 month = (month * 10) + dp[3] - '0';
607 pp->year = dp[4] - '0';
608 pp->year = (pp->year * 10) + dp[5] - '0';
612 time_t tt = time(NULL);
613 struct tm * t = gmtime(&tt);
615 month = t->tm_mon + 1;
616 pp->year= t->tm_year;
619 if (month < 1 || month > 12 || day < 1) {
620 refclock_report(peer, CEVNT_BADTIME);
624 /* Hmmmm this will be a nono for 2100,2200,2300 but I don't think I'll be here */
625 /* good thing that 2000 is a leap year */
626 /* pp->year will be 00-99 if read from GPS, 00-> (years since 1900) from tm_year */
628 if (day > day1tab[month - 1]) {
629 refclock_report(peer, CEVNT_BADTIME);
632 for (i = 0; i < month - 1; i++)
635 if (day > day2tab[month - 1]) {
636 refclock_report(peer, CEVNT_BADTIME);
639 for (i = 0; i < month - 1; i++)
647 * If the PPSAPI is working, rather use its timestamps.
648 * assume that the PPS occurs on the second so blow any msec
650 if (nmea_pps(up, &rd_tmp) == 1) {
651 pp->lastrec = up->tstamp = rd_tmp;
654 #endif /* HAVE_PPSAPI */
657 * Process the new sample in the median filter and determine the
658 * reference clock offset and dispersion. We use lastrec as both
659 * the reference time and receive time, in order to avoid being
660 * cute, like setting the reference time later than the receive
661 * time, which may cause a paranoid protocol module to chuck out
665 if (!refclock_process(pp)) {
666 refclock_report(peer, CEVNT_BADTIME);
673 * Only go on if we had been polled.
678 pp->lastref = pp->lastrec;
679 refclock_receive(peer);
681 /* If we get here - what we got from the clock is OK, so say so */
682 refclock_report(peer, CEVNT_NOMINAL);
684 record_clock_stats(&peer->srcadr, pp->a_lastcode);
689 * nmea_poll - called by the transmit procedure
691 * We go to great pains to avoid changing state here, since there may be
692 * more than one eavesdropper receiving the same timecode.
700 register struct nmeaunit *up;
701 struct refclockproc *pp;
704 up = (struct nmeaunit *)pp->unitptr;
705 if (up->pollcnt == 0)
706 refclock_report(peer, CEVNT_TIMEOUT);
713 * usually nmea_receive can get a timestamp every second
716 gps_send(pp->io.fd,"$PMOTG,RMC,0000*1D\r\n", peer);
721 * gps_send(fd,cmd, peer) Sends a command to the GPS receiver.
722 * as gps_send(fd,"rqts,u\r", peer);
724 * We don't currently send any data, but would like to send
725 * RTCM SC104 messages for differential positioning. It should
726 * also give us better time. Without a PPS output, we're
727 * Just fooling ourselves because of the serial code paths
738 if (write(fd, cmd, strlen(cmd)) == -1) {
739 refclock_report(peer, CEVNT_FAULT);
752 for (tp = cp; *tp != '\0'; tp++) {
761 int refclock_nmea_bs;
762 #endif /* REFCLOCK */