GPRMC NMEA message layout

Archiver

This is the layout of a RMC message according to the NMEA standard. As you
can see the Speed over Ground is in KNOTS.
You can see the parsing of other GPS related NMEA sentences at:

http://vancouver-webpages.com/peter/nmeafaq.txt

RMC - Recommended minimum specific GPS/Transit data
RMC,225446,A,4916.45,N,12311.12,W,000.5,054.7,191194,020.3,E*68
225446 Time of fix 22:54:46 UTC
A Navigation receiver warning A = OK, V = warning
4916.45,N Latitude 49 deg. 16.45 min North
12311.12,W Longitude 123 deg. 11.12 min West
000.5 Speed over ground, Knots
054.7 Course Made Good, True
191194 Date of fix 19 November 1994
020.3,E Magnetic variation 20.3 deg East
*68 mandatory checksum

A good resource for GPS related matters is the sci.geo.satellite-nav news
group.
_____________________________________________________

Victor Fraenckel - The Windman vfraenc1@n...

www.windsway.com
Home of the WindReader Electronic Theodolite
Read the WIND

Archiver

I looked at some code I wrote and here is the conversion I used to get the
computer to convert the Rockwell Jupiter data into a number that matched the
speedometer on my car.

(gps_value)*(1000*39.37)/(12 * 5280) = number that matches my car
speedometer

I believe that this is the conversion from kilometers/hr to miles/hr

likewise for altitude

(gps_value)*39.37/12 = feet

this is the conversion from meters to feet

either that data is for a gps that is in airplane/ship mode or the Rockwell
Jupiter is set into a metric mode and I don't know how to change it.


Also I ran across something that all of the old hands probably already know.
When I calculate distance using distance formula and two waypoints latitude
and longitude - I was expected that I would need to do some degree to linear
measure conversion - apparently a conversion is not necessary - distance
formula automatically gives you kilometers - is that right or did I mess
up? - is this correct only for small areas and small distances ? and falls
apart for greater distances ?



richard


l

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Original Message

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From: "Victorf" <vfraenc1@n...>
To: "Stamp Mailing List" <basicstamps@egroups.com >
Sent: Thursday, August 03, 2000 6:40 AM
Subject: [noparse][[/noparse]basicstamps] $GPRMC NMEA message layout


> This is the layout of a RMC message according to the NMEA standard. As you
> can see the Speed over Ground is in KNOTS.
> You can see the parsing of other GPS related NMEA sentences at:
>
> http://vancouver-webpages.com/peter/nmeafaq.txt
>
> RMC - Recommended minimum specific GPS/Transit data
> RMC,225446,A,4916.45,N,12311.12,W,000.5,054.7,191194,020.3,E*68
> 225446 Time of fix 22:54:46 UTC
> A Navigation receiver warning A = OK, V = warning
> 4916.45,N Latitude 49 deg. 16.45 min North
> 12311.12,W Longitude 123 deg. 11.12 min West
> 000.5 Speed over ground, Knots
> 054.7 Course Made Good, True
> 191194 Date of fix 19 November 1994
> 020.3,E Magnetic variation 20.3 deg East
> *68 mandatory checksum
>
> A good resource for GPS related matters is the sci.geo.satellite-nav news
> group.
> _____________________________________________________
>
> Victor Fraenckel - The Windman vfraenc1@n...
>
> www.windsway.com
> Home of the WindReader Electronic Theodolite
> Read the WIND
>
>
>
>
>