Tactical Position Reporting (APRS)

Automatic Packet Reporting System (APRS) is an amateur radio based system for real time tactical digital communications of information of immediate value in the local area. In addition, all such data is ingested into the APRS Internet system (APRS-IS) and distributed globally for instant access. In addition to messages, alerts, announcements and bulletins, the most visible aspect of APRS is its map display. Anyone may place any object or information on their map and it is distributed to all maps of all users in the local RF network or monitoring the area via the internet. Any station, radio or object that has an attached GPS is automatically tracked. Other prominent map features are weather stations, alerts and objects and other map related amateur radio volunteer activities including Search and Rescue and signal direction finding.

Equipment

Instead of configuring a full bidirectional modem (TNC), I opted for a simpler setup in which the position is simply encoded and sent over RF. This allows basic position reporting, but does not offer the more advanced features of APRS such as two-way messaging and communication. To summarize, I will include every radio amateur’s favourite, a block diagram (in my case, note the unidirectional nature of this setup):

GPS receiver --> Position Encoder --> TX 144.390MHz --> Antenna --> APRS-IS gateway