aSAM: An adaptive Simple Acoustic Modem

Underwater Acoustic Modems (UW-A) have seen significant R&D and commercial product introductions in recent years. Standards including JANUS (NATO) and JSATS (USACE), have emerged.  Yet, interoperability remains limited due to the generally proprietary nature of commercial products, the complexity and vulnerability of high bandwidth options, and high costs/size/power consumption limiting modem use in smaller and expandable platforms.    The adaptive Simple Acoustic Modem (aSAM) builds on the design philosophy of our commercial SAM-1 modem, which has achieved success in cost sensitive yet demanding applications, in particular commercial fishing.  As with SAM-1, aSAM will be small and inexpensive with minimal power consumption and low design complexity.   A frequency agile software defined modem, aSAM will boost performance by supporting modulation methods such as very high-speed high-frequency PSK burst transmissions that capitalize on advantageous aspects of underwater sound propagation, yet can be implemented in a small, low power consumption, affordable modem. aSAM will boost interoperability through JANUS compatibility.  A dual-band design, it can switch to faster modes after a JANUS link is established.  The design will encourage collaboration and third party manufacturer adoption by publishing all coding schemes and supporting code, and providing users with a development environment to implement their own coding schemes.