59 Spring 2025 Proceedings its utility as a tool for supporting other missions. One example is the Coast Guard’s interest in using AIS to transmit search and rescue (SAR) patterns directly to a vessel’s navigation system. When the Coast Guard receives a SAR case, a Coast Guard watchstander devel- ops a gridded search and rescue pattern that is opti- mized to reflect the last known position of the distressed mariner, environmental conditions such as wind and current, and available Coast Guard assets, like boats, cut- ters, rotary, and fixed-wing aircraft. This direct transfer of SAR pattern data via AIS greatly reduces the amount of time crewmembers spend manually entering coor- dinates and reduces the risk of data entry errors. Other examples of Coast Guard and port partner use cases include encrypted chat, Coast Guard and partner agency asset tracking, and target of interest messages used for law enforcement activities. However, with the increasing volume of marine ves- sels using AIS for collision avoidance and other novel uses, growing demand has led to an overload of the two AIS channels currently used for communication, which challenges the system. To address this issue, international organizations including the International Telecommunication Union, the International Maritime Organization (IMO), and the International Association of Marine Aids to Navigation and Lighthouse Authorities, have been developing standards for the next generation of AIS. Known as the VHF Data Exchange System, or VDES, this advanced maritime communication technology is designed to support the IMO’s electronic navigation goals. Using terrestrial and satellite radio communi- cation links in the VHF maritime mobile band, VDES enables global interoperable digital data exchange between ships, between ships and shore, and between ships and satellite. VDES builds upon the original capa- bilities of AIS, addressing the increasing requirements for data exchange between ships and shore and using the VHF radio spectrum more effectively and efficiently. Since 2020, the RDC has evaluated VDES through the center’s Project 8703 titled, Evaluation and Testing of VDES Impacts on the AIS. The project builds on the RDC’s foundational knowledge and years of prior AIS research, helping to inform Coast Guard stakeholders on the potential benefits of adopting VDES in the future for use within the Marine Transportation System. The RDC team identified several notable benefits of transitioning from AIS to VDES, including: • VDES (VDE-TER) offers increased capacity for Coast Guard search and rescue (SAR) response involves multimission stations, cutters, aircraft, and boats linked by communications networks. The VHF Data Exchange System may enhance the Coast Guard’s ability to quickly exchange SAR data between assets involved in a search, including distress reports, information about the distress, assigned search patterns, and results of searches. Coast Guard graphic
