108

Unix/Linux 网络时间协议版本3 Network Time Protocol Version 3 (NTP) distribution for Unix systems

Replied: Tue, 18 Mar 1997 19:21:30 -0500
Replied: "Marc Brett <[e-mail]> [e-mail], [e-mail],
Replied: [e-mail]"
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From: Marc Brett <[e-mail]>
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Date: Tue, 18 Mar 1997 13:00:43 +0000
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To: [e-mail]
Subject: Updates to MX 4200 driver
Cc: [e-mail], [e-mail], 
    [e-mail]
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Harlan,

Here are some updates to the MX 4200 driver, based on the xntp3-5.89.8 code.

The main new features are:

	o  Allowed operation on either fixed or mobile platforms (eg. ships)
	o  Added leap second debug information to the syslog
	o  Added receiver mode information to the syslog
	o  Reduced the total number of messages coming from the receiver

Best Regards,

Marc Brett


-- 
Marc Brett                     Western Atlas
[e-mail]            [phone]

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*** driver9.html.orig	Tue Mar 18 11:03:01 1997
--- html/driver9.html	Tue Mar 18 11:03:25 1997
***************
*** 27,45 ****
  <p>This driver supports all compatible receivers such as the 6-channel
  MX 4200, MX 4200D, and the 12-channel MX 9212, MX 9012R, MX 9112.
  
! <p>This driver assumes that the GPS antenna is in a fixed location.  The
! receiver is initially placed in a "Static, 3D Nav" mode, where latitude,
! longitude, elevation and time are calculated for a fixed station.  A
! DOP-weighted running average position is calculated from this data.
! After 24 hours, the receiver is placed into a "Known Position" mode,
! initialized with the calculated position, and then solves only for time.
! 
! <p>The requirement for a fixed installation precludes operation of
! this driver aboard moving ships, aircraft, or land vehicles.  Also,
! the position averaging algorithm does not take into account boundary
! conditions, so operation very near the international date line or the
! poles is not recommended.
  
  <p><h4>Monitor Data</h4>
  
  <p>The driver writes each timecode as received to the
--- 27,52 ----
  <p>This driver supports all compatible receivers such as the 6-channel
  MX 4200, MX 4200D, and the 12-channel MX 9212, MX 9012R, MX 9112.
  
! <p><h4>Operating Modes</h4>
  
+ <p>This driver supports two modes of operation, static and mobile,
+ controlled by clock flag 2.
+ 
+ <p>In static mode (the default) the driver assumes that the GPS antenna
+ is in a fixed location.  The receiver is initially placed in a "Static,
+ 3D Nav" mode, where latitude, longitude, elevation and time are
+ calculated for a fixed station.  A DOP-weighted running average position
+ is calculated from this data.  After 24 hours, the receiver is placed
+ into a "Known Position" mode, initialized with the calculated position,
+ and then solves only for time.  The position averaging algorithm does
+ not take into account boundary conditions, so this mode of operation
+ very near the international date line or the poles is not recommended.
+ 
+ <p>In mobile mode, the driver assumes the GPS antenna is mounted on
+ a moving platform such as a car, ship, or aircraft.  The receiver is
+ placed in "Dynamic, 3D Nav" mode and solves for position, altitude and
+ time while moving.  No position averaging is performed.
+ 
  <p><h4>Monitor Data</h4>
  
  <p>The driver writes each timecode as received to the
***************
*** 69,78 ****
  <dd>Not used by this driver.
  
  <p><dt><code>flag2 0 | 1</code>
! <dd>Not used by this driver.
  
  <p><dt><code>flag3 0 | 1</code>
! <dd>Enable <code>ppsclock</code> line discipline/streams module if set.
  
  <p><dt><code>flag4 0 | 1</code>
  <dd>Not used by this driver.
--- 76,85 ----
  <dd>Not used by this driver.
  
  <p><dt><code>flag2 0 | 1</code>
! <dd>Assume GPS receiver is on a mobile platform if set.
  
  <p><dt><code>flag3 0 | 1</code>
! <dd>Not used by this driver.
  
  <p><dt><code>flag4 0 | 1</code>
  <dd>Not used by this driver.

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*** refclock_mx4200.c.orig	Wed Feb 19 04:37:48 1997
--- xntpd/refclock_mx4200.c	Tue Mar 18 12:04:39 1997
***************
*** 98,109 ****
  #define	DESCRIPTION	"Magnavox MX4200 GPS Receiver" /* who we are */
  #define	DEFFUDGETIME	0	/* default fudge time (ms) */
  
  /*
   * Position Averaging.
   * Reference: Dr. Thomas A. Clark's Totally Accurate Clock (TAC) files at
   * ftp://aleph.gsfc.nasa.gov/GPS/totally.accurate.clock/
   */
- #define MAX_VEL_SQUARED	(1.0)	/* Maximum acceptable velocity (squared) (m/s)*/
  #define INTERVAL	1	/* Interval between position measurements (s) */
  #define AVGING_TIME	24	/* Number of hours to average */
  #define USUAL_EDOP	0.75	/* used for normalizing EDOP */
--- 98,110 ----
  #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.
   * Reference: Dr. Thomas A. Clark's Totally Accurate Clock (TAC) files at
   * ftp://aleph.gsfc.nasa.gov/GPS/totally.accurate.clock/
   */
  #define INTERVAL	1	/* Interval between position measurements (s) */
  #define AVGING_TIME	24	/* Number of hours to average */
  #define USUAL_EDOP	0.75	/* used for normalizing EDOP */
***************
*** 153,161 ****
  	double edop;			/* EDOP (east DOP) */
  	double ndop;			/* NDOP (north DOP) */
  	double vdop;			/* VDOP (vertical DOP) */
! 	u_int  moving;			/* are we moving? */
  	u_int  known;			/* position known yet? */
  	u_long clamp_time;		/* when to stop postion averaging */
  	int    coderecv;		/* total received samples */
  	int    nkeep;			/* number of samples to preserve */
  	int    rshift;			/* number of rshifts for division */
--- 154,165 ----
  	double edop;			/* EDOP (east DOP) */
  	double ndop;			/* NDOP (north DOP) */
  	double vdop;			/* VDOP (vertical DOP) */
! 	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 */
  	int    coderecv;		/* total received samples */
  	int    nkeep;			/* number of samples to preserve */
  	int    rshift;			/* number of rshifts for division */
***************
*** 218,224 ****
  	register struct mx4200unit *up;
  	struct refclockproc *pp;
  	int fd;
- 	int i;
  	char gpsdev[20];
  
  	/*
--- 222,227 ----
***************
*** 261,296 ****
  	pp->clockdesc = DESCRIPTION;
  	memcpy((char *)&pp->refid, REFID, 4);
  
- 	up->pollcnt  = 2;
- 	up->polled   = 0;
- 	up->moving   = 0;	/* not moving */
- 	up->known    = 0;	/* not moving */
- 	up->avg_lat  = 0.0;
- 	up->avg_lon  = 0.0;
- 	up->avg_alt  = 0.0;
- 	up->filt_lat = 0.0;
- 	up->filt_lon = 0.0;
- 	up->filt_alt = 0.0;
- 	up->edop     = USUAL_EDOP;
- 	up->ndop     = USUAL_NDOP;
- 	up->vdop     = USUAL_VDOP;
- 	up->clamp_time = current_time + (AVGING_TIME * 60 * 60);
- 	up->coderecv = 0;
- 	up->nkeep    = NKEEP;
- 	if (up->nkeep > NSAMPLES) up->nkeep = NSAMPLES;
- 	if (up->nkeep >=   1) up->rshift =  0;
- 	if (up->nkeep >=   2) up->rshift =  1;
- 	if (up->nkeep >=   4) up->rshift =  2;
- 	if (up->nkeep >=   8) up->rshift =  3;
- 	if (up->nkeep >=  16) up->rshift =  4;
- 	if (up->nkeep >=  32) up->rshift =  5;
- 	if (up->nkeep >=  64) up->rshift =  6;
- 	up->nkeep =1;
- 	i = up->rshift;
- 	while (i > 0) {
- 		up->nkeep *= 2;
- 		i--;
- 	}
  
  	/* Ensure the receiver is properly configured */
  	mx4200_config(peer);
--- 264,269 ----
***************
*** 323,328 ****
--- 296,304 ----
  mx4200_config(peer)
  	struct peer *peer;
  {
+ 	char tr_mode;
+ 	char add_mode;
+ 	int i;
  	register struct mx4200unit *up;
  	struct refclockproc *pp;
  
***************
*** 330,335 ****
--- 306,357 ----
  	up = (struct mx4200unit *)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->filt_lat    = 0.0;
+ 	up->filt_lon    = 0.0;
+ 	up->filt_alt    = 0.0;
+ 	up->edop        = USUAL_EDOP;
+ 	up->ndop        = USUAL_NDOP;
+ 	up->vdop        = USUAL_VDOP;
+ 	up->last_leap   = 0;	/* LEAP_NOWARNING */
+ 	up->clamp_time  = current_time + (AVGING_TIME * 60 * 60);
+ 	up->log_time    = current_time + SLEEPTIME;
+ 	up->coderecv    = 0;
+ 	up->nkeep       = NKEEP;
+ 	if (up->nkeep > NSAMPLES) up->nkeep = NSAMPLES;
+ 	if (up->nkeep >=   1) up->rshift = 0;
+ 	if (up->nkeep >=   2) up->rshift = 1;
+ 	if (up->nkeep >=   4) up->rshift = 2;
+ 	if (up->nkeep >=   8) up->rshift = 3;
+ 	if (up->nkeep >=  16) up->rshift = 4;
+ 	if (up->nkeep >=  32) up->rshift = 5;
+ 	if (up->nkeep >=  64) up->rshift = 6;
+ 	up->nkeep =1;
+ 	i = up->rshift;
+ 	while (i > 0) {
+ 		up->nkeep *= 2;
+ 		i--;
+ 	}
+ 
+ 	/*
  	 * "007" Control Port Configuration
  	 * Zero the output list (do it twice to flush possible junk)
  	 */
***************
*** 392,400 ****
  	 * (Set field 1 'S' == static  if we are not moving).
  	 * (Set field 1 'K' == known position if we can initialize lat/lon/alt).
  	 */
  	mx4200_send(peer, "%s,%03d,%c,%c,%c,%d,%d,%d,", pmvxg,
  	    PMVXG_S_TRECOVCONF,
! 	    'S',	/* static: solve for pos, alt, time, while stationary */
  	    'U',	/* synchronize to UTC */
  	    'A',	/* always output a time pulse */
  	    500,	/* max time error in ns */
--- 414,438 ----
  	 * (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';
+ 		add_mode = 0;
+ 	} else {
+ 		/* static: solve for pos, alt, time, while stationary */
+ 		tr_mode = 'S';
+ 		add_mode = 1;
+ 	}
  	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 */
***************
*** 403,421 ****
  			/* Multi-satellite mode */
  
  	/*
! 	 * "007" Control Port Configuration
! 	 * Output "004" mode data
  	 */
! 	mx4200_send(peer, "%s,%03d,%03d,%d,%d,,%d,,,", pmvxg,
! 	    PMVXG_S_PORTCONF,
! 	    PMVXG_D_MODEDATA, /* control port output block Label */
! 	    0,		/* clear current output control list (0=no) */
! 	    1,		/* add/delete sentences from list (1=add) */
! 			/* must be null */
! 	    INTERVAL*10);/* sentence output rate (sec) */
! 	    		/* precision for position output */
! 			/* nmea version for cga & gll output */
! 			/* pass-through control */
  
  	/*
  	 * "007" Control Port Configuration
--- 441,454 ----
  			/* Multi-satellite mode */
  
  	/*
! 	 * Output position information (to calculate fixed installation
! 	 * location) only if we are not moving
  	 */
! 	if (up->moving) {
! 		add_mode = 0;	/* delete from list */
! 	} else {
! 		add_mode = 1;	/* add to list */
! 	}
  
  	/*
  	 * "007" Control Port Configuration
***************
*** 425,431 ****
  	    PMVXG_S_PORTCONF,
  	    PMVXG_D_DOPS, /* control port output block Label */
  	    0,		/* clear current output control list (0=no) */
! 	    1,		/* add/delete sentences from list (1=add) */
  			/* must be null */
  	    INTERVAL);	/* sentence output rate (sec) */
  	    		/* precision for position output */
--- 458,464 ----
  	    PMVXG_S_PORTCONF,
  	    PMVXG_D_DOPS, /* control port output block Label */
  	    0,		/* clear current output control list (0=no) */
! 	    add_mode,	/* add/delete sentences from list (1=add) */
  			/* must be null */
  	    INTERVAL);	/* sentence output rate (sec) */
  	    		/* precision for position output */
***************
*** 432,451 ****
  			/* nmea version for cga & gll output */
  			/* pass-through control */
  
- 	/*
- 	 * "007" Control Port Configuration
- 	 * Output "523" time recovery parameters currently in use
- 	 */
- 	mx4200_send(peer, "%s,%03d,%03d,%d,%d,,%d,,,", pmvxg,
- 	    PMVXG_S_PORTCONF,
- 	    PMVXG_D_TRECOVUSEAGE, /* control port output block Label */
- 	    0,		/* clear current output control list (0=no) */
- 	    1,		/* add/delete sentences from list (1=add) */
- 			/* must be null */
- 	    INTERVAL*10); /* sentence output rate (sec) */
- 	    		/* precision for position output */
- 			/* nmea version for cga & gll output */
- 			/* pass-through control */
  
  	/*
  	 * "007" Control Port Configuration
--- 465,470 ----
***************
*** 455,468 ****
  	    PMVXG_S_PORTCONF,
  	    PMVXG_D_PHV, /* control port output block Label */
  	    0,		/* clear current output control list (0=no) */
! 	    1,		/* add/delete sentences from list (1=add) */
  			/* must be null */
  	    INTERVAL);	/* sentence output rate (sec) */
  	    		/* precision for position output */
  			/* nmea version for cga & gll output */
  			/* pass-through control */
- 
- 
  }
  
  /*
--- 474,485 ----
  	    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) */
  			/* must be null */
  	    INTERVAL);	/* sentence output rate (sec) */
  	    		/* precision for position output */
  			/* nmea version for cga & gll output */
  			/* pass-through control */
  }
  
  /*
***************
*** 481,486 ****
--- 498,511 ----
  	pp = peer->procptr;
  	up = (struct mx4200unit *)pp->unitptr;
  
+ 	/* Should never happen! */
+ 	if (up->moving) return;
+ 
+ 	/*
+ 	 * Set up to output status information in the near future
+ 	 */