Results of ADS communications testing

Automated dependent surveillance or ADS is an improvement to current vessel traffic service (VTS) operations and a step towards a “voiceless VTS.” The two main requirements for an ADS system are an accurate position sensor on the vessel and a communications link between the vessel and the vessel traffic center (VTC). The first is satisfied by the operational United States Coast Guard differential GPS (DGPS) service. The second has been the subject of research. Three existing communications technologies were evaluated and tested: advanced mobile phone service (AMPS) cellular, VHF-FM digital selective calling (DSC), and Newcomb L-Band Satellite. These communications methods were tested in the Narragansett Bay Rhode Island area and evaluated according to the following criteria: coverage area, reliability, integrity, reporting interval, latency, and cost. Of the three communications methods, the DSC and Newcomb Satellite technologies were found to be well-suited for ADS implementation