D-STAR Position Reporting System (DPRS)
Some D-Star radios have integrated GPS capabilities, and others can have a GPS unit plugged into them. These radios are capable of transmitting thier positions over the low-rate data channel of a D-STAR repeater at regular intervals.
Many D-STAR repeaters (gateways) run a software application to send these DPRS packets into the APRS-IS. Once they are in the APRS-IS network, they are treated as a standard APRS beacon.
The difference between a DPRS and APRS message is that DPRS only supports an ALPHA SSID (A-Z) where APRS only supports a NUMERIC SSID (0-15). This means that a station that has transmitted a position via DPRS can be easily identified due to the letter following thier callsign (often -P for Portable or -M for Mobile)
More information on D-STAR operation in Australia can be found here.