Kenwood TM-255A User Manual

4 GPS

14

TM-D710A/E

The latitude and longitude information required by the GPS receiver does not allow for accurate 
representation of the unevenness of the Earth’s surface.  For use with GPS, the current standard 
that defines the precise shape of the Earth is called WGS-84.  By using this standard in 
conjunction with mapping standards for each country, accurate position plotting on a map can be 
done.

Although position can be described in many different formats, such as degrees, degrees and 
minutes, and degrees, minutes and seconds, the GPS system and APRS have standardized on 
the degrees and decimal minutes format.  Just like it is important to use proper international 
phonetics when spelling on the air, it is important in APRS as in any communications system to 
have a default standard for position.  All operators should be trained to use the DDD MM.mm 
format by default in voice communications just like in the data formats.  Using these standards on 
the air will prevent communications errors, confusion, repeats, and conversions.
APRS Standard:

Latitude

DD MM.mm 
(degrees and minutes)

39 49.31N 
+39 49.31

Longitude

DDD MM.mm 
(degrees and minutes)

84 15.39W 
-84 15.39