NMEA Info

[Sea Angel]

I have found an interesting and informative link for the NEMA standards and notes. I can even understand some it.

www.kh-gps.de/nmea-faq.htm

Hope this will help someone along the way...
I do not recall this being on the site, but I have been wrong before....

Sea Angel

Topic title edited by Da Nag

[tpbrady]

Art,

I tried your link but it comes up page not found. I did post a document in the documents sections that described NMEA input and output formats. I don't know how it compares to what you found, but I found it helpful for me in troubleshooting file transfers between GPS's.

[Sea Angel]

MY! MY! MY!

My Senior Moments are getting better! My apologies to ALL. The title of this thread should be NMEA. I have tried to change it, but at last I am not smart enough to do this. I will have to leave it to the Great DATA WIZZZZss.


This is my English version of the referenced site-

HTTP://WWW.KH-GPS.DE/NMEA-FAQ.HTM

I have moved it into WORD and pasted it here. I hope this helps. If more info is desired, I will try to get the FAQs and place them out here.

The below text runs the defining identifications of all the structured data words used by the GPS, LORAN and other marine equipments. Normally an equipment's installation manual will give customized codes. Since all this data is in an a standard computer ASCII text format, it is possible for a laptop cpu to be used to read this info.

________________________________________
NMEA 0183
Version vom 7. August 2002
________________________________________
NMEA is a standard protocol, use by GPS receivers to transmit data. NMEA output is EIA-422A but for most purposes you can consider it RS-232 compatible. Use 4800 bps, 8 data bits, no parity and one stop bit ( 8N1 ). NMEA 0183 sentences are all ASCII. Each sentence begins with a dollarsign ($) and ends with a carriage return linefeed (<CR><LF>). Data is comma delimited. All commas must be included as they act as markers. Some GPS do not send some of the fields. A checksum is optionally added (in a few cases it is manatory). Following the $ is the address field aaccc. aa is the device id. GP is used to identify GPS data. Transmission of the device ID is usually optional. ccc is the sentence formatter, otherwise known as the sentence name.
Here are the most important sentences ( for more infos read the text-file NMEA-FAQ ) :
________________________________________
Eine sehr gute Seite zum Thema findet man auch hier : http://rpss28.uni-regensburg.de:8080/PiechullaWeb/NMEA0183/
________________________________________
RMB
$GPRMB,A,x.x,a,c--c,d--d,llll.ll,e,yyyyy.yy,f,g.g,h.h,i.i,j*kk

RMB = Recommended Minimum Navigation Information

1 = Data Status (V=navigation receiver warning)
2 = Crosstrack error in nautical miles
3 = Direction to steer (L or R) to correct error
4 = Origin waypoint ID#
5 = Destination waypoint ID#
6 = Destination waypoint latitude
7 = N or S
8 = Destination waypoint longitude
9 = E or W
10 = Range to destination in nautical miles
11 = Bearing to destination, degrees True
12 = Destination closing velocity in knots
13 = Arrival status; (A=entered or perpendicular passed)
14 = Checksum
________________________________________
• RMC
$GPRMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,ddmmyy,x.x,a*hh

RMC = Recommended Minimum Specific GPS/TRANSIT Data

1 = UTC of position fix
2 = Data status (V=navigation receiver warning)
3 = Latitude of fix
4 = N or S
5 = Longitude of fix
6 = E or W
7 = Speed over ground in knots
8 = Track made good in degrees True
9 = UT date
10 = Magnetic variation degrees (Easterly var. subtracts from true course)
11 = E or W
12 = Checksum
________________________________________
• GGA
$GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh

GGA = Global Positioning System Fix Data

1 = UTC of Position
2 = Latitude
3 = N or S
4 = Longitude
5 = E or W
6 = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix)
7 = Number of satellites in use [not those in view]
8 = Horizontal dilution of position
9 = Antenna altitude above/below mean sea level (geoid)
10 = Meters (Antenna height unit)
11 = Geoidal separation (Diff. between WGS-84 earth ellipsoid and
mean sea level. -=geoid is below WGS-84 ellipsoid)
12 = Meters (Units of geoidal separation)
13 = Age in seconds since last update from diff. reference station
14 = Diff. reference station ID#
15 = Checksum
________________________________________
• VTG
$GPVTG,t,T,,,s.ss,N,s.ss,K*hh

VTG = Actual track made good and speed over ground

1 = Track made good
2 = Fixed text 'T' indicates that track made good is relative to true north
3 = not used
4 = not used
5 = Speed over ground in knots
6 = Fixed text 'N' indicates that speed over ground in in knots
7 = Speed over ground in kilometers/hour
8 = Fixed text 'K' indicates that speed over ground is in kilometers/hour
9 = Checksum
________________________________________
• RMA
$GPRMA,A,llll.ll,N,lllll.ll,W,,,ss.s,ccc,vv.v,W*hh

RMA = Navigation data from present position

1 = Data status
2 = Latitude
3 = N/S
4 = longitude
5 = W/E
6 = not used
7 = not used
8 = Speed over ground in knots
9 = Course over ground
10 = Variation
11 = Direction of variation E/W
12 = Checksum
________________________________________
• GSA
$GPGSA,A,3,19,28,14,18,27,22,31,39,,,,,1.7,1.0,1.3*35

GSA = GPS receiver operating mode, SVs used for navigation, and DOP values.

1 = Mode:
M=Manual, forced to operate in 2D or 3D
A=Automatic, 3D/2D
2 = Mode:
1=Fix not available
2=2D
3=3D
3-14 = IDs of SVs used in position fix (null for unused fields)
15 = PDOP
16 = HDOP
17 = VDOP
________________________________________
• GSV
$GPGSV,4,1,13,02,02,213,,03,-3,000,,11,00,121,,14,13,172,05*67
GSV = Number of SVs in view, PRN numbers, elevation, azimuth & SNR values.
1 = Total number of messages of this type in this cycle
2 = Message number
3 = Total number of SVs in view
4 = SV PRN number
5 = Elevation in degrees, 90 maximum
6 = Azimuth, degrees from true north, 000 to 359
7 = SNR, 00-99 dB (null when not tracking)
8-11 = Information about second SV, same as field 4-7
12-15= Information about third SV, same as field 4-7
16-19= Information about fourth SV, same as field 4-7
________________________________________

Any one's thoughts on this? Too much info??

Sea Angel

[stevej]

More than you ever wanted to know about GPS systems
http://gpsinformation.net/

When I was setting up my laptop I pulled one of the utilities of of this site that plots accuracy number of satellites and a bunch of other stuff.

Pretty good site has all of the NEMA info, tutorials, evals on and on.

stevej

[Da Nag]

[Sea Angel]

Thanks Bill;
I see that my "typo" carried to someone else. This I should have caught, thoo the "typo" is a valid standards re-fense.... soooooo... I try tu du bettea next tyme.

I DID correct the first message address to prevent future carry overs.

Sea Angel