JANUS: Lingua Franca

JANUS is an emergent underwater communications standard for `initial contact'. JANUS can serve as an underwater beacon to broadcast information. It is free for public use. The current status of the standard and the areas of its application are presented. The results from multiple governmental programs, recent experiments and early commercial adoptions are provided. Several at-sea data telemetry projects are discussed including between fixed and mobile nodes capable of communicating using multiple physical layer solutions. An overview of the progress and the ongoing efforts for the public and open standard are considered. The utility of JANUS is outlined as an aid for autonomous underwater vehicle navigation by exploiting the infrastructure from cargo ships, wind farms, underwater instrumentation, etc. The relevance of the SUNRISE and Forward-Deployed Energy & Communications Outpost programs are discussed.