RMC - Recommended Minimum Specific GPS/Transit Data

RMC - Recommended Minimum Specific GPS/Transit Data

This command enables the GPRMC recommended minimum specific GPS/transit data message and determines the rate at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either to output this message once (polled), or to output this message at the indicated update rate (continuously). Once the receiver is set to continuous output, the continuous flow can be stopped by sending a one-time (polled) output request. The receiver will output the response one final time, and then terminate any further message outputs. The value of the periodic rate is retained through a power cycle only if battery back-up power is applied.

If the receiver has just powered up and has yet to compute a position fix (status field (a) is be invalid), then the time (hhmmss.ss) and date (ddmmyy) fields will be nulled. If the receiver is not computing a position fix sometime after the first fix (status field (a) is invalid), then the time (hhmmss.ss) and date (ddmmyy) fields will be frozen. If the receiver is not computing a position fix (status field (a) is invalid), then the speed over ground (z.z) and track made good (y.y) fields will be nulled.

NOTE

The magnetic variation field (d.d) will always be zero since the GT GPS does not have this information.

Input Command

• Set response message rate:

  $PMOTG,RMC,yyyyCC

  yyyy	update rate	0 .. 9999 seconds
  CC	optional checksum

Response Message

• Response to above command at selected rate:

  $GPRMC,hhmmss.ss,a,ddmm.mmmm,n,dddmm.mmmm,w,z.z,y.y,ddmmyy,d.d,v*CC

  hhmmss.ss	UTC of position fix
  hh	hours	00 .. 24
  mm	minutes	00 .. 59
  ss.ss	seconds	00.000 .. 59.99
  a	status	A = valid
  		V = invalid
  ddmm.mmmm,n	latitude
  dd	degrees	00 .. 90
  mm.mmm	minutes	00.000 .. 59.999
  n	direction	N = north, S = south
  dddmm.mmmm,w	longitude
  ddd	degrees	000 .. 180
  mm.mmm	minutes	00.00 .. 59.9999
  w	direction	E = east, W = west
  z.z	speed over ground (knots)	0.0
  y.y	track made good (reference to true north)	0.0 .. 359.9
  ddmmyy	UTC date of position fix
  dd	day	01 .. 31
  mm	month	01 .. 12
  yy	year	00 .. 99
  d.d	magnetic variation (degrees)	0.0 .. 180.0
  v	variation sense	E = east
  		W = west
  CC	checksum