APRS stands for Automatic Position Reporting System. It was first developed by Bob Bruninga,WB4APR .

APRS has several uses It:

•  Can be used for public service events such as races.
•  Can be interfaced with weather stations to transmit real-time weather data.
•  Can be used in emergency communications.
•  Can be used to facilitate real-time instant messaging via Amateur Radio.
• Can be used to observe HF Band Conditions.
• Can be used to transmit position, and speed of any type of vehicle.
• Can be used to track space craft.

       APRS is very different from its predecessor packet. The difference being that using conventional packet you have to connect to another station to talk to it. APRS uses a "broadcast" of packets that normally are not addressed to one particular station. It is more efficient than conventional packet. One advantage of APRS is that all traffic that comes across a local digipeater can be gated onto the internet and onto the HF APRS frequency. This allows users to send messages though the internet to a regular email address or another station that is normally out of range.
          Another thing that makes it very different is the fact that each fixed station acts as a digipeater. This is setup so that if one mobile station cannot hit the wide area digipeater but it can hit a fixed user than that fixed user can digipeat to the wide digipeater increasing the range of mobile users.
  To learn about how to setup your own aprs station click here!!