/* $NetBSD: refclock_mx4200.c,v 1.7 2024/08/18 20:47:18 christos Exp $ */
/*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66.
*
* Copyright (c) 1992 The Regents of the University of California.
* All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory.
* 4. The name of the University may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
/*
* Modified: Marc Brett <
[email protected]> Sept, 1999.
*
* 1. Added support for alternate PPS schemes, with code mostly
* copied from the Oncore driver (Thanks, Poul-Henning Kamp).
* This code runs on SunOS 4.1.3 with ppsclock-1.6a1 and Solaris 7.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#if defined(REFCLOCK) && defined(CLOCK_MX4200) && defined(HAVE_PPSAPI)
#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_refclock.h"
#include "ntp_unixtime.h"
#include "ntp_stdlib.h"
#include <stdio.h>
#include <ctype.h>
#include "mx4200.h"
#ifdef HAVE_SYS_TERMIOS_H
# include <sys/termios.h>
#endif
#ifdef HAVE_SYS_PPSCLOCK_H
# include <sys/ppsclock.h>
#endif
#ifndef HAVE_STRUCT_PPSCLOCKEV
struct ppsclockev {
# ifdef HAVE_STRUCT_TIMESPEC
struct timespec tv;
# else
struct timeval tv;
# endif
u_int serial;
};
#endif /* ! HAVE_STRUCT_PPSCLOCKEV */
#ifdef HAVE_PPSAPI
# include "ppsapi_timepps.h"
#endif /* HAVE_PPSAPI */
/*
* This driver supports the Magnavox Model MX 4200 GPS Receiver
* adapted to precision timing applications. It requires the
* ppsclock line discipline or streams module described in the
* Line Disciplines and Streams Drivers page. It also requires a
* gadget box and 1-PPS level converter, such as described in the
* Pulse-per-second (PPS) Signal Interfacing page.
*
* It's likely that other compatible Magnavox receivers such as the
* MX 4200D, MX 9212, MX 9012R, MX 9112 will be supported by this code.
*/
/*
* Check this every time you edit the code!
*/
#define YEAR_LAST_MODIFIED 2000
/*
* GPS Definitions
*/
#define DEVICE "/dev/gps%d" /* device name and unit */
#define SPEED232 B4800 /* baud */
/*
* Radio interface parameters
*/
#define PRECISION (-18) /* precision assumed (about 4 us) */
#define REFID "GPS\0" /* reference id */
#define DESCRIPTION "Magnavox MX4200 GPS Receiver" /* who we are */
#define DEFFUDGETIME 0 /* default fudge time (ms) */
#define SLEEPTIME 32 /* seconds to wait for reconfig to complete */
/*
* Position Averaging.
*/
#define INTERVAL 1 /* Interval between position measurements (s) */
#define AVGING_TIME 24 /* Number of hours to average */
#define NOT_INITIALIZED -9999. /* initial pivot longitude */
/*
* MX4200 unit control structure.
*/
struct mx4200unit {
u_int pollcnt; /* poll message counter */
u_int polled; /* Hand in a time sample? */
u_int lastserial; /* last pps serial number */
struct ppsclockev ppsev; /* PPS control structure */
double avg_lat; /* average latitude */
double avg_lon; /* average longitude */
double avg_alt; /* average height */
double central_meridian; /* central meridian */
double N_fixes; /* Number of position measurements */
int last_leap; /* leap second warning */
u_int moving; /* mobile platform? */
u_long sloppyclockflag; /* fudge flags */
u_int known; /* position known yet? */
u_long clamp_time; /* when to stop postion averaging */
u_long log_time; /* when to print receiver status */
pps_handle_t pps_h;
pps_params_t pps_p;
pps_info_t pps_i;
};
static char pmvxg[] = "PMVXG";
/* XXX should be somewhere else */
#ifdef __GNUC__
#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
#ifndef __attribute__
#define __attribute__(args)
#endif /* __attribute__ */
#endif /* __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) */
#else
#ifndef __attribute__
#define __attribute__(args)
#endif /* __attribute__ */
#endif /* __GNUC__ */
/* XXX end */
/*
* Function prototypes
*/
static int mx4200_start (int, struct peer *);
static void mx4200_shutdown (int, struct peer *);
static void mx4200_receive (struct recvbuf *);
static void mx4200_poll (int, struct peer *);
static char * mx4200_parse_t (struct peer *);
static char * mx4200_parse_p (struct peer *);
static char * mx4200_parse_s (struct peer *);
int mx4200_cmpl_fp (const void *, const void *);
static int mx4200_config (struct peer *);
static void mx4200_ref (struct peer *);
static void mx4200_send (struct peer *, char *, ...)
__attribute__ ((format (printf, 2, 3)));
static u_char mx4200_cksum (char *, int);
static int mx4200_jday (int, int, int);
static void mx4200_debug (struct peer *, char *, ...)
__attribute__ ((format (printf, 2, 3)));
static int mx4200_pps (struct peer *);
/*
* Transfer vector
*/
struct refclock refclock_mx4200 = {
mx4200_start, /* start up driver */
mx4200_shutdown, /* shut down driver */
mx4200_poll, /* transmit poll message */
noentry, /* not used (old mx4200_control) */
noentry, /* initialize driver (not used) */
noentry, /* not used (old mx4200_buginfo) */
NOFLAGS /* not used */
};
/*
* mx4200_start - open the devices and initialize data for processing
*/
static int
mx4200_start(
int unit,
struct peer *peer
)
{
register struct mx4200unit *up;
struct refclockproc *pp;
int fd;
char gpsdev[20];
/*
* Open serial port
*/
snprintf(gpsdev, sizeof(gpsdev), DEVICE, unit);
fd = refclock_open(&peer->srcadr, gpsdev, SPEED232, LDISC_PPS);
if (fd <= 0)
return 0;
/*
* Allocate unit structure
*/
up = emalloc_zero(sizeof(*up));
pp = peer->procptr;
pp->io.clock_recv = mx4200_receive;
pp->io.srcclock = peer;
pp->io.datalen = 0;
pp->io.fd = fd;
if (!io_addclock(&pp->io)) {
close(fd);
pp->io.fd = -1;
free(up);
return (0);
}
pp->unitptr = up;
/*
* Initialize miscellaneous variables
*/
peer->precision = PRECISION;
pp->clockdesc = DESCRIPTION;
memcpy((char *)&pp->refid, REFID, 4);
/* Ensure the receiver is properly configured */
return mx4200_config(peer);
}
/*
* mx4200_shutdown - shut down the clock
*/
static void
mx4200_shutdown(
int unit,
struct peer *peer
)
{
register struct mx4200unit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = pp->unitptr;
if (-1 != pp->io.fd)
io_closeclock(&pp->io);
if (NULL != up)
free(up);
}
/*
* mx4200_config - Configure the receiver
*/
static int
mx4200_config(
struct peer *peer
)
{
char tr_mode;
int add_mode;
register struct mx4200unit *up;
struct refclockproc *pp;
int mode;
pp = peer->procptr;
up = pp->unitptr;
/*
* Initialize the unit variables
*
* STRANGE BEHAVIOUR WARNING: The fudge flags are not available
* at the time mx4200_start is called. These are set later,
* and so the code must be prepared to handle changing flags.
*/
up->sloppyclockflag = pp->sloppyclockflag;
if (pp->sloppyclockflag & CLK_FLAG2) {
up->moving = 1; /* Receiver on mobile platform */
msyslog(LOG_DEBUG, "mx4200_config: mobile platform");
} else {
up->moving = 0; /* Static Installation */
}
up->pollcnt = 2;
up->polled = 0;
up->known = 0;
up->avg_lat = 0.0;
up->avg_lon = 0.0;
up->avg_alt = 0.0;
up->central_meridian = NOT_INITIALIZED;
up->N_fixes = 0.0;
up->last_leap = 0; /* LEAP_NOWARNING */
up->clamp_time = current_time + (AVGING_TIME * 60 * 60);
up->log_time = current_time + SLEEPTIME;
if (time_pps_create(pp->io.fd, &up->pps_h) < 0) {
perror("time_pps_create");
msyslog(LOG_ERR,
"mx4200_config: time_pps_create failed: %m");
return (0);
}
if (time_pps_getcap(up->pps_h, &mode) < 0) {
msyslog(LOG_ERR,
"mx4200_config: time_pps_getcap failed: %m");
return (0);
}
if (time_pps_getparams(up->pps_h, &up->pps_p) < 0) {
msyslog(LOG_ERR,
"mx4200_config: time_pps_getparams failed: %m");
return (0);
}
/* nb. only turn things on, if someone else has turned something
* on before we get here, leave it alone!
*/
up->pps_p.mode = PPS_CAPTUREASSERT | PPS_TSFMT_TSPEC;
up->pps_p.mode &= mode; /* only set what is legal */
if (time_pps_setparams(up->pps_h, &up->pps_p) < 0) {
perror("time_pps_setparams");
msyslog(LOG_ERR,
"mx4200_config: time_pps_setparams failed: %m");
exit(1);
}
if (time_pps_kcbind(up->pps_h, PPS_KC_HARDPPS, PPS_CAPTUREASSERT,
PPS_TSFMT_TSPEC) < 0) {
perror("time_pps_kcbind");
msyslog(LOG_ERR,
"mx4200_config: time_pps_kcbind failed: %m");
exit(1);
}
/*
* "007" Control Port Configuration
* Zero the output list (do it twice to flush possible junk)
*/
mx4200_send(peer, "%s,%03d,,%d,,,,,,", pmvxg,
PMVXG_S_PORTCONF,
/* control port output block Label */
1); /* clear current output control list (1=yes) */
/* add/delete sentences from list */
/* must be null */
/* sentence output rate (sec) */
/* precision for position output */
/* nmea version for cga & gll output */
/* pass-through control */
mx4200_send(peer, "%s,%03d,,%d,,,,,,", pmvxg,
PMVXG_S_PORTCONF, 1);
/*
* Request software configuration so we can syslog the firmware version
*/
mx4200_send(peer, "%s,%03d", "CDGPQ", PMVXG_D_SOFTCONF);
/*
* "001" Initialization/Mode Control, Part A
* Where ARE we?
*/
mx4200_send(peer, "%s,%03d,,,,,,,,,,", pmvxg,
PMVXG_S_INITMODEA);
/* day of month */
/* month of year */
/* year */
/* gmt */
/* latitude DDMM.MMMM */
/* north/south */
/* longitude DDDMM.MMMM */
/* east/west */
/* height */
/* Altitude Reference 1=MSL */
/*
* "001" Initialization/Mode Control, Part B
* Start off in 2d/3d coast mode, holding altitude to last known
* value if only 3 satellites available.
*/
mx4200_send(peer, "%s,%03d,%d,,%.1f,%.1f,%d,%d,%d,%c,%d",
pmvxg, PMVXG_S_INITMODEB,
3, /* 2d/3d coast */
/* reserved */
0.1, /* hor accel fact as per Steve (m/s**2) */
0.1, /* ver accel fact as per Steve (m/s**2) */
10, /* vdop */
10, /* hdop limit as per Steve */
5, /* elevation limit as per Steve (deg) */
'U', /* time output mode (UTC) */
0); /* local time offset from gmt (HHHMM) */
/*
* "023" Time Recovery Configuration
* Get UTC time from a stationary receiver.
* (Set field 1 'D' == dynamic if we are on a moving platform).
* (Set field 1 'S' == static if we are not moving).
* (Set field 1 'K' == known position if we can initialize lat/lon/alt).
*/
if (pp->sloppyclockflag & CLK_FLAG2)
up->moving = 1; /* Receiver on mobile platform */
else
up->moving = 0; /* Static Installation */
up->pollcnt = 2;
if (up->moving) {
/* dynamic: solve for pos, alt, time, while moving */
tr_mode = 'D';
} else {
/* static: solve for pos, alt, time, while stationary */
tr_mode = 'S';
}
mx4200_send(peer, "%s,%03d,%c,%c,%c,%d,%d,%d,", pmvxg,
PMVXG_S_TRECOVCONF,
tr_mode, /* time recovery mode (see above ) */
'U', /* synchronize to UTC */
'A', /* always output a time pulse */
500, /* max time error in ns */
0, /* user bias in ns */
1); /* output "830" sentences to control port */
/* Multi-satellite mode */
/*
* Output position information (to calculate fixed installation
* location) only if we are not moving
*/
if (up->moving) {
add_mode = 2; /* delete from list */
} else {
add_mode = 1; /* add to list */
}
/*
* "007" Control Port Configuration
* Output "021" position, height, velocity reports
*/
mx4200_send(peer, "%s,%03d,%03d,%d,%d,,%d,,,", pmvxg,
PMVXG_S_PORTCONF,
PMVXG_D_PHV, /* control port output block Label */
0, /* clear current output control list (0=no) */
add_mode, /* add/delete sentences from list (1=add, 2=del) */
/* must be null */
INTERVAL); /* sentence output rate (sec) */
/* precision for position output */
/* nmea version for cga & gll output */
/* pass-through control */
return (1);
}
/*
* mx4200_ref - Reconfigure unit as a reference station at a known position.
*/
static void
mx4200_ref(
struct peer *peer
)
{
register struct mx4200unit *up;
struct refclockproc *pp;
double minute, lat, lon, alt;
char lats[16], lons[16];
char nsc, ewc;
pp = peer->procptr;
up = pp->unitptr;
/* Should never happen! */
if (up->moving) return;
/*
* Set up to output status information in the near future
*/
up->log_time = current_time + SLEEPTIME;
/*
* "007" Control Port Configuration
* Stop outputting "021" position, height, velocity reports
*/
mx4200_send(peer, "%s,%03d,%03d,%d,%d,,,,,", pmvxg,
PMVXG_S_PORTCONF,
PMVXG_D_PHV, /* control port output block Label */
0, /* clear current output control list (0=no) */
2); /* add/delete sentences from list (2=delete) */
/* must be null */
/* sentence output rate (sec) */
/* precision for position output */
/* nmea version for cga & gll output */
/* pass-through control */
/*
* "001" Initialization/Mode Control, Part B
* Put receiver in fully-constrained 2d nav mode
*/
mx4200_send(peer, "%s,%03d,%d,,%.1f,%.1f,%d,%d,%d,%c,%d",
pmvxg, PMVXG_S_INITMODEB,
2, /* 2d nav */
/* reserved */
0.1, /* hor accel fact as per Steve (m/s**2) */
0.1, /* ver accel fact as per Steve (m/s**2) */
10, /* vdop */
10, /* hdop limit as per Steve */
5, /* elevation limit as per Steve (deg) */
'U', /* time output mode (UTC) */
0); /* local time offset from gmt (HHHMM) */
/*
* "023" Time Recovery Configuration
* Get UTC time from a stationary receiver. Solve for time only.
* This should improve the time resolution dramatically.
*/
mx4200_send(peer, "%s,%03d,%c,%c,%c,%d,%d,%d,", pmvxg,
PMVXG_S_TRECOVCONF,
'K', /* known position: solve for time only */
'U', /* synchronize to UTC */
'A', /* always output a time pulse */
500, /* max time error in ns */
0, /* user bias in ns */
1); /* output "830" sentences to control port */
/* Multi-satellite mode */
/*
* "000" Initialization/Mode Control - Part A
* Fix to our averaged position.
*/
if (up->central_meridian != NOT_INITIALIZED) {
up->avg_lon += up->central_meridian;
if (up->avg_lon < -180.0) up->avg_lon += 360.0;
if (up->avg_lon > 180.0) up->avg_lon -= 360.0;
}
if (up->avg_lat >= 0.0) {
lat = up->avg_lat;
nsc = 'N';
} else {
lat = up->avg_lat * (-1.0);
nsc = 'S';
}
if (up->avg_lon >= 0.0) {
lon = up->avg_lon;
ewc = 'E';
} else {
lon = up->avg_lon * (-1.0);
ewc = 'W';
}
alt = up->avg_alt;
minute = (lat - (double)(int)lat) * 60.0;
snprintf(lats, sizeof(lats), "%02d%02.4f", (int)lat, minute);
minute = (lon - (double)(int)lon) * 60.0;
snprintf(lons, sizeof(lons), "%03d%02.4f", (int)lon, minute);
mx4200_send(peer, "%s,%03d,,,,,%s,%c,%s,%c,%.2f,%d", pmvxg,
PMVXG_S_INITMODEA,
/* day of month */
/* month of year */
/* year */
/* gmt */
lats, /* latitude DDMM.MMMM */
nsc, /* north/south */
lons, /* longitude DDDMM.MMMM */
ewc, /* east/west */
alt, /* Altitude */
1); /* Altitude Reference (0=WGS84 ellipsoid, 1=MSL geoid)*/
msyslog(LOG_DEBUG,
"mx4200: reconfig to fixed location: %s %c, %s %c, %.2f m",
lats, nsc, lons, ewc, alt );
}
/*
* mx4200_poll - mx4200 watchdog routine
*/
static void
mx4200_poll(
int unit,
struct peer *peer
)
{
register struct mx4200unit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = pp->unitptr;
/*
* You don't need to poll this clock. It puts out timecodes
* once per second. If asked for a timestamp, take note.
* The next time a timecode comes in, it will be fed back.
*/
/*
* If we haven't had a response in a while, reset the receiver.
*/
if (up->pollcnt > 0) {
up->pollcnt--;
} else {
refclock_report(peer, CEVNT_TIMEOUT);
/*
* Request a "000" status message which should trigger a
* reconfig
*/
mx4200_send(peer, "%s,%03d",
"CDGPQ", /* query from CDU to GPS */
PMVXG_D_STATUS); /* label of desired sentence */
}
/*
* polled every 64 seconds. Ask mx4200_receive to hand in
* a timestamp.
*/
up->polled = 1;
pp->polls++;
/*
* Output receiver status information.
*/
if ((up->log_time > 0) && (current_time > up->log_time)) {
up->log_time = 0;
/*
* Output the following messages once, for debugging.
* "004" Mode Data
* "523" Time Recovery Parameters
*/
mx4200_send(peer, "%s,%03d", "CDGPQ", PMVXG_D_MODEDATA);
mx4200_send(peer, "%s,%03d", "CDGPQ", PMVXG_D_TRECOVUSEAGE);
}
}
static char char2hex[] = "0123456789ABCDEF";
/*
* mx4200_receive - receive gps data
*/
static void
mx4200_receive(
struct recvbuf *rbufp
)
{
register struct mx4200unit *up;
struct refclockproc *pp;
struct peer *peer;
char *cp;
int sentence_type;
u_char ck;
/*
* Initialize pointers and read the timecode and timestamp.
*/
peer = rbufp->recv_peer;
pp = peer->procptr;
up = pp->unitptr;
/*
* If operating mode has been changed, then reinitialize the receiver
* before doing anything else.
*/
if ((pp->sloppyclockflag & CLK_FLAG2) !=
(up->sloppyclockflag & CLK_FLAG2)) {
up->sloppyclockflag = pp->sloppyclockflag;
mx4200_debug(peer,
"mx4200_receive: mode switch: reset receiver\n");
mx4200_config(peer);
return;
}
up->sloppyclockflag = pp->sloppyclockflag;
/*
* Read clock output. Automatically handles STREAMS, CLKLDISC.
*/
pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &pp->lastrec);
/*
* There is a case where <cr><lf> generates 2 timestamps.
*/
if (pp->lencode == 0)
return;
up->pollcnt = 2;
pp->a_lastcode[pp->lencode] = '\0';
record_clock_stats(&peer->srcadr, pp->a_lastcode);
mx4200_debug(peer, "mx4200_receive: %d %s\n",
pp->lencode, pp->a_lastcode);
/*
* The structure of the control port sentences is based on the
* NMEA-0183 Standard for interfacing Marine Electronics
* Navigation Devices (Version 1.5)
*
* $PMVXG,XXX, ....................*CK<cr><lf>
*
* $ Sentence Start Identifier (reserved char)
* (Start-of-Sentence Identifier)
* P Special ID (Proprietary)
* MVX Originator ID (Magnavox)
* G Interface ID (GPS)
* , Field Delimiters (reserved char)
* XXX Sentence Type
* ...... Data
* * Checksum Field Delimiter (reserved char)
* CK Checksum
* <cr><lf> Carriage-Return/Line Feed (reserved chars)
* (End-of-Sentence Identifier)
*
* Reject if any important landmarks are missing.
*/
cp = pp->a_lastcode + pp->lencode - 3;
if (cp < pp->a_lastcode || *pp->a_lastcode != '$' || cp[0] != '*' ) {
mx4200_debug(peer, "mx4200_receive: bad format\n");
refclock_report(peer, CEVNT_BADREPLY);
return;
}
/*
* Check and discard the checksum
*/
ck = mx4200_cksum(&pp->a_lastcode[1], pp->lencode - 4);
if (char2hex[ck >> 4] != cp[1] || char2hex[ck & 0xf] != cp[2]) {
mx4200_debug(peer, "mx4200_receive: bad checksum\n");
refclock_report(peer, CEVNT_BADREPLY);
return;
}
*cp = '\0';
/*
* Get the sentence type.
*/
sentence_type = 0;
if ((cp = strchr(pp->a_lastcode, ',')) == NULL) {
mx4200_debug(peer, "mx4200_receive: no sentence\n");
refclock_report(peer, CEVNT_BADREPLY);
return;
}
cp++;
sentence_type = strtol(cp, &cp, 10);
/*
* Process the sentence according to its type.
*/
switch (sentence_type) {
/*
* "000" Status message
*/
case PMVXG_D_STATUS:
/*
* XXX
* Since we configure the receiver to not give us status
* messages and since the receiver outputs status messages by
* default after being reset to factory defaults when sent the
* "$PMVXG,018,C\r\n" message, any status message we get
* indicates the reciever needs to be initialized; thus, it is
* not necessary to decode the status message.
*/
if ((cp = mx4200_parse_s(peer)) != NULL) {
mx4200_debug(peer,
"mx4200_receive: status: %s\n", cp);
}
mx4200_debug(peer, "mx4200_receive: reset receiver\n");
mx4200_config(peer);
break;
/*
* "021" Position, Height, Velocity message,
* if we are still averaging our position
*/
case PMVXG_D_PHV:
if (!up->known) {
/*
* Parse the message, calculating our averaged position.
*/
if ((cp = mx4200_parse_p(peer)) != NULL) {
mx4200_debug(peer, "mx4200_receive: pos: %s\n", cp);
return;
}
mx4200_debug(peer,
"mx4200_receive: position avg %f %.9f %.9f %.4f\n",
up->N_fixes, up->avg_lat, up->avg_lon, up->avg_alt);
/*
* Reinitialize as a reference station
* if position is well known.
*/
if (current_time > up->clamp_time) {
up->known++;
mx4200_debug(peer, "mx4200_receive: reconfiguring!\n");
mx4200_ref(peer);
}
}
break;
/*
* Print to the syslog:
* "004" Mode Data
* "030" Software Configuration
* "523" Time Recovery Parameters Currently in Use
*/
case PMVXG_D_MODEDATA:
case PMVXG_D_SOFTCONF:
case PMVXG_D_TRECOVUSEAGE:
if ((cp = mx4200_parse_s(peer)) != NULL) {
mx4200_debug(peer,
"mx4200_receive: multi-record: %s\n", cp);
}
break;
/*
* "830" Time Recovery Results message
*/
case PMVXG_D_TRECOVOUT:
/*
* Capture the last PPS signal.
* Precision timestamp is returned in pp->lastrec
*/
if (0 != mx4200_pps(peer)) {
mx4200_debug(peer, "mx4200_receive: pps failure\n");
refclock_report(peer, CEVNT_FAULT);
return;
}
/*
* Parse the time recovery message, and keep the info
* to print the pretty billboards.
*/
if ((cp = mx4200_parse_t(peer)) != NULL) {
mx4200_debug(peer, "mx4200_receive: time: %s\n", cp);
refclock_report(peer, CEVNT_BADREPLY);
return;
}
/*
* Add the new sample to a median filter.
*/
if (!refclock_process(pp)) {
mx4200_debug(peer,"mx4200_receive: offset: %.6f\n",
pp->offset);
refclock_report(peer, CEVNT_BADTIME);
return;
}
/*
* The clock will blurt a timecode every second but we only
* want one when polled. If we havn't been polled, bail out.
*/
if (!up->polled)
return;
/*
* Return offset and dispersion to control module. We use
* lastrec as both the reference time and receive time in
* order to avoid being cute, like setting the reference time
* later than the receive time, which may cause a paranoid
* protocol module to chuck out the data.
*/
mx4200_debug(peer, "mx4200_receive: process time: ");
mx4200_debug(peer, "%4d-%03d %02d:%02d:%02d at %s, %.6f\n",
pp->year, pp->day, pp->hour, pp->minute, pp->second,
prettydate(&pp->lastrec), pp->offset);
pp->lastref = pp->lastrec;
refclock_receive(peer);
/*
* We have succeeded in answering the poll.
* Turn off the flag and return
*/
up->polled = 0;
break;
/*
* Ignore all other sentence types
*/
default:
break;
} /* switch (sentence_type) */
return;
}
/*
* Parse a mx4200 time recovery message. Returns a string if error.
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,830,T,YYYY,MM,DD,HH:MM:SS,U,S,FFFFFF,PPPPP,BBBBBB,LL
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 830=Time Recovery Results
* This sentence is output approximately 1 second
* preceding the 1PPS output. It indicates the
* exact time of the next pulse, whether or not the
* time mark will be valid (based on operator-specified
* error tolerance), the time to which the pulse is
* synchronized, the receiver operating mode,
* and the time error of the *last* 1PPS output.
* 1 char Time Mark Valid: T=Valid, F=Not Valid
* 2 int Year: 1993-
* 3 int Month of Year: 1-12
* 4 int Day of Month: 1-31
* 5 int Time of Day: HH:MM:SS
* 6 char Time Synchronization: U=UTC, G=GPS
* 7 char Time Recovery Mode: D=Dynamic, S=Static,
* K=Known Position, N=No Time Recovery
* 8 int Oscillator Offset: The filter's estimate of the oscillator
* frequency error, in parts per billion (ppb).
* 9 int Time Mark Error: The computed error of the *last* pulse
* output, in nanoseconds.
* 10 int User Time Bias: Operator specified bias, in nanoseconds
* 11 int Leap Second Flag: Indicates that a leap second will
* occur. This value is usually zero, except during
* the week prior to the leap second occurrence, when
* this value will be set to +1 or -1. A value of
* +1 indicates that GPS time will be 1 second
* further ahead of UTC time.
*
*/
static char *
mx4200_parse_t(
struct peer *peer
)
{
struct refclockproc *pp;
struct mx4200unit *up;
char time_mark_valid, time_sync, op_mode;
int sentence_type, valid;
int year, day_of_year, month, day_of_month;
int hour, minute, second, leapsec_warn;
int oscillator_offset, time_mark_error, time_bias;
pp = peer->procptr;
up = pp->unitptr;
leapsec_warn = 0; /* Not all receivers output leap second warnings (!) */
sscanf(pp->a_lastcode,
"$PMVXG,%d,%c,%d,%d,%d,%d:%d:%d,%c,%c,%d,%d,%d,%d",
&sentence_type, &time_mark_valid, &year, &month, &day_of_month,
&hour, &minute, &second, &time_sync, &op_mode,
&oscillator_offset, &time_mark_error, &time_bias, &leapsec_warn);
if (sentence_type != PMVXG_D_TRECOVOUT)
return ("wrong rec-type");
switch (time_mark_valid) {
case 'T':
valid = 1;
break;
case 'F':
valid = 0;
break;
default:
return ("bad pulse-valid");
}
switch (time_sync) {
case 'G':
return ("synchronized to GPS; should be UTC");
case 'U':
break; /* UTC -> ok */
default:
return ("not synchronized to UTC");
}
/*
* Check for insane time (allow for possible leap seconds)
*/
if (second > 60 || minute > 59 || hour > 23 ||
second < 0 || minute < 0 || hour < 0) {
mx4200_debug(peer,
"mx4200_parse_t: bad time %02d:%02d:%02d",
hour, minute, second);
if (leapsec_warn != 0)
mx4200_debug(peer, " (leap %+d\n)", leapsec_warn);
mx4200_debug(peer, "\n");
refclock_report(peer, CEVNT_BADTIME);
return ("bad time");
}
if ( second == 60 ) {
msyslog(LOG_DEBUG,
"mx4200: leap second! %02d:%02d:%02d",
hour, minute, second);
}
/*
* Check for insane date
* (Certainly can't be any year before this code was last altered!)
*/
if (day_of_month > 31 || month > 12 ||
day_of_month < 1 || month < 1 || year < YEAR_LAST_MODIFIED) {
mx4200_debug(peer,
"mx4200_parse_t: bad date (%4d-%02d-%02d)\n",
year, month, day_of_month);
refclock_report(peer, CEVNT_BADDATE);
return ("bad date");
}
/*
* Silly Hack for MX4200:
* ASCII message is for *next* 1PPS signal, but we have the
* timestamp for the *last* 1PPS signal. So we have to subtract
* a second. Discard if we are on a month boundary to avoid
* possible leap seconds and leap days.
*/
second--;
if (second < 0) {
second = 59;
minute--;
if (minute < 0) {
minute = 59;
hour--;
if (hour < 0) {
hour = 23;
day_of_month--;
if (day_of_month < 1) {
return ("sorry, month boundary");
}
}
}
}
/*
* Calculate Julian date
*/
if (!(day_of_year = mx4200_jday(year, month, day_of_month))) {
mx4200_debug(peer,
"mx4200_parse_t: bad julian date %d (%4d-%02d-%02d)\n",
day_of_year, year, month, day_of_month);
refclock_report(peer, CEVNT_BADDATE);
return("invalid julian date");
}
/*
* Setup leap second indicator
*/
switch (leapsec_warn) {
case 0:
pp->leap = LEAP_NOWARNING;
break;
case 1:
pp->leap = LEAP_ADDSECOND;
break;
case -1:
pp->leap = LEAP_DELSECOND;
break;
default:
pp->leap = LEAP_NOTINSYNC;
}
/*
* Any change to the leap second warning status?
*/
if (leapsec_warn != up->last_leap ) {
msyslog(LOG_DEBUG,
"mx4200: leap second warning: %d to %d (%d)",
up->last_leap, leapsec_warn, pp->leap);
}
up->last_leap = leapsec_warn;
/*
* Copy time data for billboard monitoring.
*/
pp->year = year;
pp->day = day_of_year;
pp->hour = hour;
pp->minute = minute;
pp->second = second;
/*
* Toss if sentence is marked invalid
*/
if (!valid || pp->leap == LEAP_NOTINSYNC) {
mx4200_debug(peer, "mx4200_parse_t: time mark not valid\n");
refclock_report(peer, CEVNT_BADTIME);
return ("pulse invalid");
}
return (NULL);
}
/*
* Calculate the checksum
*/
static u_char
mx4200_cksum(
register char *cp,
register int n
)
{
register u_char ck;
for (ck = 0; n-- > 0; cp++)
ck ^= *cp;
return (ck);
}
/*
* Tables to compute the day of year. Viva la leap.
*/
static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/*
* Calculate the the Julian Day
*/
static int
mx4200_jday(
int year,
int month,
int day_of_month
)
{
register int day, i;
int leap_year;
/*
* Is this a leap year ?
*/
if (year % 4) {
leap_year = 0; /* FALSE */
} else {
if (year % 100) {
leap_year = 1; /* TRUE */
} else {
if (year % 400) {
leap_year = 0; /* FALSE */
} else {
leap_year = 1; /* TRUE */
}
}
}
/*
* Calculate the Julian Date
*/
day = day_of_month;
if (leap_year) {
/* a leap year */
if (day > day2tab[month - 1]) {
return (0);
}
for (i = 0; i < month - 1; i++)
day += day2tab[i];
} else {
/* not a leap year */
if (day > day1tab[month - 1]) {
return (0);
}
for (i = 0; i < month - 1; i++)
day += day1tab[i];
}
return (day);
}
/*
* Parse a mx4200 position/height/velocity sentence.
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,021,SSSSSS.SS,DDMM.MMMM,N,DDDMM.MMMM,E,HHHHH.H,GGGG.G,EEEE.E,WWWW.W,MM
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 021=Position, Height Velocity Data
* This sentence gives the receiver position, height,
* navigation mode, and velocity north/east.
* *This sentence is intended for post-analysis
* applications.*
* 1 float UTC measurement time (seconds into week)
* 2 float WGS-84 Lattitude (degrees, minutes)
* 3 char N=North, S=South
* 4 float WGS-84 Longitude (degrees, minutes)
* 5 char E=East, W=West
* 6 float Altitude (meters above mean sea level)
* 7 float Geoidal height (meters)
* 8 float East velocity (m/sec)
* 9 float West Velocity (m/sec)
* 10 int Navigation Mode
* Mode if navigating:
* 1 = Position from remote device
* 2 = 2-D position
* 3 = 3-D position
* 4 = 2-D differential position
* 5 = 3-D differential position
* 6 = Static
* 8 = Position known -- reference station
* 9 = Position known -- Navigator
* Mode if not navigating:
* 51 = Too few satellites
* 52 = DOPs too large
* 53 = Position STD too large
* 54 = Velocity STD too large
* 55 = Too many iterations for velocity
* 56 = Too many iterations for position
* 57 = 3 sat startup failed
* 58 = Command abort
*/
static char *
mx4200_parse_p(
struct peer *peer
)
{
struct refclockproc *pp;
struct mx4200unit *up;
int sentence_type, mode;
double mtime, lat, lon, alt, geoid, vele, veln;
char north_south, east_west;
pp = peer->procptr;
up = pp->unitptr;
/* Should never happen! */
if (up->moving) return ("mobile platform - no pos!");
sscanf ( pp->a_lastcode,
"$PMVXG,%d,%lf,%lf,%c,%lf,%c,%lf,%lf,%lf,%lf,%d",
&sentence_type, &mtime, &lat, &north_south, &lon, &east_west,
&alt, &geoid, &vele, &veln, &mode);
/* Sentence type */
if (sentence_type != PMVXG_D_PHV)
return ("wrong rec-type");
/*
* return if not navigating
*/
if (mode > 10)
return ("not navigating");
if (mode != 3 && mode != 5)
return ("not navigating in 3D");
/* Latitude (always +ve) and convert DDMM.MMMM to decimal */
if (lat < 0.0) return ("negative latitude");
if (lat > 9000.0) lat = 9000.0;
lat *= 0.01;
lat = ((int)lat) + (((lat - (int)lat)) * 1.6666666666666666);
/* North/South */
switch (north_south) {
case 'N':
break;
case 'S':
lat *= -1.0;
break;
default:
return ("invalid north/south indicator");
}
/* Longitude (always +ve) and convert DDDMM.MMMM to decimal */
if (lon < 0.0) return ("negative longitude");
if (lon > 180.0) lon = 180.0;
lon *= 0.01;
lon = ((int)lon) + (((lon - (int)lon)) * 1.6666666666666666);
/* East/West */
switch (east_west) {
case 'E':
break;
case 'W':
lon *= -1.0;
break;
default:
return ("invalid east/west indicator");
}
/*
* Normalize longitude to near 0 degrees.
* Assume all data are clustered around first reading.
*/
if (up->central_meridian == NOT_INITIALIZED) {
up->central_meridian = lon;
mx4200_debug(peer,
"mx4200_receive: central meridian = %.9f \n",
up->central_meridian);
}
lon -= up->central_meridian;
if (lon < -180.0) lon += 360.0;
if (lon > 180.0) lon -= 360.0;
/*
* Calculate running averages
*/
up->avg_lon = (up->N_fixes * up->avg_lon) + lon;
up->avg_lat = (up->N_fixes * up->avg_lat) + lat;
up->avg_alt = (up->N_fixes * up->avg_alt) + alt;
up->N_fixes += 1.0;
up->avg_lon /= up->N_fixes;
up->avg_lat /= up->N_fixes;
up->avg_alt /= up->N_fixes;
mx4200_debug(peer,
"mx4200_receive: position rdg %.0f: %.9f %.9f %.4f (CM=%.9f)\n",
up->N_fixes, lat, lon, alt, up->central_meridian);
return (NULL);
}
/*
* Parse a mx4200 Status sentence
* Parse a mx4200 Mode Data sentence
* Parse a mx4200 Software Configuration sentence
* Parse a mx4200 Time Recovery Parameters Currently in Use sentence
* (used only for logging raw strings)
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,000,XXX,XX,X,HHMM,X
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 000=Status.
* Returns status of the receiver to the controller.
* 1 Current Receiver Status:
* ACQ = Satellite re-acquisition
* ALT = Constellation selection
* COR = Providing corrections (for reference stations only)
* IAC = Initial acquisition
* IDL = Idle, no satellites
* NAV = Navigation
* STS = Search the Sky (no almanac available)
* TRK = Tracking
* 2 Number of satellites that should be visible
* 3 Number of satellites being tracked
* 4 Time since last navigation status if not currently navigating
* (hours, minutes)
* 5 Initialization status:
* 0 = Waiting for initialization parameters
* 1 = Initialization completed
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,004,C,R,D,H.HH,V.VV,TT,HHHH,VVVV,T
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 004=Software Configuration.
* Defines the navigation mode and criteria for
* acceptable navigation for the receiver.
* 1 Constrain Altitude Mode:
* 0 = Auto. Constrain altitude (2-D solution) and use
* manual altitude input when 3 sats avalable. Do
* not constrain altitude (3-D solution) when 4 sats
* available.
* 1 = Always constrain altitude (2-D solution).
* 2 = Never constrain altitude (3-D solution).
* 3 = Coast. Constrain altitude (2-D solution) and use
* last GPS altitude calculation when 3 sats avalable.
* Do not constrain altitude (3-D solution) when 4 sats
* available.
* 2 Altitude Reference: (always 0 for MX4200)
* 0 = Ellipsoid
* 1 = Geoid (MSL)
* 3 Differential Navigation Control:
* 0 = Disabled
* 1 = Enabled
* 4 Horizontal Acceleration Constant (m/sec**2)
* 5 Vertical Acceleration Constant (m/sec**2) (0 for MX4200)
* 6 Tracking Elevation Limit (degrees)
* 7 HDOP Limit
* 8 VDOP Limit
* 9 Time Output Mode:
* U = UTC
* L = Local time
* 10 Local Time Offset (minutes) (absent on MX4200)
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,030,NNNN,FFF
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 030=Software Configuration.
* This sentence contains the navigation processor
* and baseband firmware version numbers.
* 1 Nav Processor Version Number
* 2 Baseband Firmware Version Number
*
* A typical message looks like this. Checksum has already been stripped.
*
* $PMVXG,523,M,S,M,EEEE,BBBBBB,C,R
*
* Field Field Contents
* ----- --------------
* Block Label: $PMVXG
* Sentence Type: 523=Time Recovery Parameters Currently in Use.
* This sentence contains the configuration of the
* time recovery feature of the receiver.
* 1 Time Recovery Mode:
* D = Dynamic; solve for position and time while moving
* S = Static; solve for position and time while stationary
* K = Known position input, solve for time only
* N = No time recovery
* 2 Time Synchronization:
* U = UTC time
* G = GPS time
* 3 Time Mark Mode:
* A = Always output a time pulse
* V = Only output time pulse if time is valid (as determined
* by Maximum Time Error)
* 4 Maximum Time Error - the maximum error (in nanoseconds) for
* which a time mark will be considered valid.
* 5 User Time Bias - external bias in nanoseconds
* 6 Time Message Control:
* 0 = Do not output the time recovery message
* 1 = Output the time recovery message (record 830) to
* Control port
* 2 = Output the time recovery message (record 830) to
* Equipment port
* 7 Reserved
* 8 Position Known PRN (absent on MX 4200)
*
*/
static char *
mx4200_parse_s(
struct peer *peer
)
{
struct refclockproc *pp;
struct mx4200unit *up;
int sentence_type;
pp = peer->procptr;
up = pp->unitptr;
sscanf ( pp->a_lastcode, "$PMVXG,%d", &sentence_type);
/* Sentence type */
switch (sentence_type) {
case PMVXG_D_STATUS:
msyslog(LOG_DEBUG,
"mx4200: status: %s", pp->a_lastcode);
break;
case PMVXG_D_MODEDATA:
msyslog(LOG_DEBUG,
"mx4200: mode data: %s", pp->a_lastcode);
break;
case PMVXG_D_SOFTCONF:
msyslog(LOG_DEBUG,
"mx4200: firmware configuration: %s", pp->a_lastcode);
break;
case PMVXG_D_TRECOVUSEAGE:
msyslog(LOG_DEBUG,
"mx4200: time recovery parms: %s", pp->a_lastcode);
break;
default:
return ("wrong rec-type");
}
return (NULL);
}
/*
* Process a PPS signal, placing a timestamp in pp->lastrec.
*/
static int
mx4200_pps(
struct peer *peer
)
{
int temp_serial;
struct refclockproc *pp;
struct mx4200unit *up;
struct timespec timeout;
pp = peer->procptr;
up = pp->unitptr;
/*
* Grab the timestamp of the PPS signal.
*/
temp_serial = up->pps_i.assert_sequence;
timeout.tv_sec = 0;
timeout.tv_nsec = 0;
if (time_pps_fetch(up->pps_h, PPS_TSFMT_TSPEC, &(up->pps_i),
&timeout) < 0) {
mx4200_debug(peer,
"mx4200_pps: time_pps_fetch: serial=%lu, %m\n",
(unsigned long)up->pps_i.assert_sequence);
refclock_report(peer, CEVNT_FAULT);
return(1);
}
if (temp_serial == up->pps_i.assert_sequence) {
mx4200_debug(peer,
"mx4200_pps: assert_sequence serial not incrementing: %lu\n",
(unsigned long)up->pps_i.assert_sequence);
refclock_report(peer, CEVNT_FAULT);
return(1);
}
/*
* Check pps serial number against last one
*/
if (up->lastserial + 1 != up->pps_i.assert_sequence &&
up->lastserial != 0) {
if (up->pps_i.assert_sequence == up->lastserial) {
mx4200_debug(peer, "mx4200_pps: no new pps event\n");
} else {
mx4200_debug(peer, "mx4200_pps: missed %lu pps events\n",
up->pps_i.assert_sequence - up->lastserial - 1UL);
}
refclock_report(peer, CEVNT_FAULT);
}
up->lastserial = up->pps_i.assert_sequence;
/*
* Return the timestamp in pp->lastrec
*/
pp->lastrec.l_ui = up->pps_i.assert_timestamp.tv_sec +
(u_int32) JAN_1970;
pp->lastrec.l_uf = ((double)(up->pps_i.assert_timestamp.tv_nsec) *
4.2949672960) + 0.5;
return(0);
}
/*
* mx4200_debug - print debug messages
*/
static void
mx4200_debug(struct peer *peer, char *fmt, ...)
{
#ifdef DEBUG
va_list ap;
struct refclockproc *pp;
struct mx4200unit *up;
if (debug) {
va_start(ap, fmt);
pp = peer->procptr;
up = pp->unitptr;
/*
* Print debug message to stdout
* In the future, we may want to get get more creative...
*/
mvprintf(fmt, ap);
va_end(ap);
}
#endif
}
/*
* Send a character string to the receiver. Checksum is appended here.
*/
#if defined(__STDC__)
static void
mx4200_send(struct peer *peer, char *fmt, ...)
#else
static void
mx4200_send(peer, fmt, va_alist)
struct peer *peer;
char *fmt;
va_dcl
#endif /* __STDC__ */
{
struct refclockproc *pp;
struct mx4200unit *up;
register char *cp, *ep;
register int n, m;
va_list ap;
char buf[1024];
u_char ck;
pp = peer->procptr;
up = pp->unitptr;
cp = buf;
ep = cp + sizeof(buf);
*cp++ = '$';
#if defined(__STDC__)
va_start(ap, fmt);
#else
va_start(ap);
#endif /* __STDC__ */
n = VSNPRINTF((cp, (size_t)(ep - cp), fmt, ap));
va_end(ap);
if (n < 0 || (size_t)n >= (size_t)(ep - cp))
goto overflow;
ck = mx4200_cksum(cp, n);
cp += n;
n = SNPRINTF((cp, (size_t)(ep - cp), "*%02X\r\n", ck));
if (n < 0 || (size_t)n >= (size_t)(ep - cp))
goto overflow;
cp += n;
m = write(pp->io.fd, buf, (unsigned)(cp - buf));
if (m < 0)
msyslog(LOG_ERR, "mx4200_send: write: %m (%s)", buf);
mx4200_debug(peer, "mx4200_send: %d %s\n", m, buf);
overflow:
msyslog(LOG_ERR, "mx4200_send: %s", "data exceeds buffer size");
}
#else
NONEMPTY_TRANSLATION_UNIT
#endif /* REFCLOCK */
