"VHFRadioBuff" wrote

I've been surfing the web, reading about APRS but I am confused
about one thing. How does the GPS play into the whole thing?

APRS is designed to report "positions." These positions are derived from
some kind of NMEA 0183 protocol device.

Any GPS that provides a serial output, NMEA 0193, and WGS 84
based position references would be acceptable. I like Garmin products.

Check out the Geko 301 (Wow!)

People in other parts of the world may use a different datum then WGS 84,
and their position may not correlate well to U.S. based maps.


[GPS with WGS 84 datum and serial port NMEA]
[Data modulator]
[Radio]

Most people use a tracker device based on a one-chip PIC processor,
and run that to a radio.

As people move around the tracker decodes the NMEA lat/lon/speed
and/or altitude, and modulates the radio and signals the PTT.