Join Date: Aug 2010
rmb, rmc with Geonav 4c and Furuno
I have a setup aboard that can handle two gps's: a Geonav 4c and a Furuno
GP31. I choose either one of them to be in operation. To show the information, there is a Clipper GPS
repeater. As soon as I put in a waypoint in the Furuno
, the clipper show COG, SOG, DTW and Bearing. As soon as I do the same on the Geonav (Furuno switched off), the same information is shown, however the display of the clipper is blinking. Having a look at the NMEA 0183
data, I notice some differences:
$FRRMC = Furuno
$ECRMC = Geonav 4c
RMC - NMEA has its own version of essential gps pvt (position, velocity, time) data. It is called RMC, The Recommended Minimum, which will look similar to:
RMC Recommended Minimum sentence C
123519 Fix taken at 12:35:19 UTC
A Status A=active or V=Void.
4807.038,N Latitude 48 deg 07.038' N
01131.000,E Longitude 11 deg 31.000' E
022.4 Speed over the ground in knots
084.4 Track angle in degrees True
230394 Date - 23rd of March 1994
003.1,W Magnetic Variation
*6A The checksum data, always begins with *
Note that, as of the 2.3 release of NMEA, there is a new field in the RMC sentence at the end just prior to the checksum. For more information on this field see here.
A Data status A = OK, V = warning
0.66,L Cross-track error (nautical miles, 9.9 max.),
steer Left to correct (or R = right)
003 Origin waypoint ID
004 Destination waypoint ID
4917.24,N Destination waypoint latitude 49 deg. 17.24 min. N
12309.57,W Destination waypoint longitude 123 deg. 09.57 min. W
001.3 Range to destination, nautical mil
052.5 True bearing to destination
000.5 Velocity towards destination, knots
V Arrival alarm A = arrived, V = not arrived
*0B mandatory checksum
It's noticeable that there is no velocity towards destination (,,) and a contrary arrival alarm
I also noticed that GGA has is missing a date.
Enclosed two nmea-data files.
Anyone who has the same experience or is willing to help me to sort this out?
Thanks in advance!