Software Acoustic Modem for TAK Communications with Analog Radios at the Tactical Edge

From disaster relief to combat search and rescue, mobile devices are increasingly key to mission success at the tactical edge. These mobile devices typically rely on networked communications to fulfil some of their most important functions. Unfortunately, due to cost, complexity, internal processes or other factors in both military and civilian scenarios, Internet Protocol (IP) networks are not always available to support such communications. Analog radios, in the form of everything from general purpose COTS walkie talkies to DoD tactical handhelds, are often all that is accessible. Today's mobile devices and applications, such as the Android Tactical Assault Kit (ATAK) – a phone-based situational awareness tool, cannot send their digital data directly over analog signals, however, and thus historically have been unable to capitalize on this large set of prevalent and often affordable radios around them. The Handheld Acoustic Modem for Mobile Exchanges with Radios (HAMMER) ATAK plugin is a software acoustic modem that allows ATAK devices to communicate with each other using any voice-comms capable radio, without the need for additional hardware. This paper describes the HAMMER technology, its military and civilian applications, current challenges and constraints, and evaluates the tool in several contexts.