Communications technologies for automated dependent surveillance

A new concept known as automated dependent surveillance or ADS is introduced. ADS is an improvement to current vessel traffic service (VTS) operations. One of the enabling technologies for the ADS concept is the advent of differential GPS. The other necessary requirement is a communications link between the vessel and the vessel traffic center (VTC). That is the subject of this paper. Existing communications technologies were evaluated and the three most promising selected for further testing: Advanced Mobile Phone Service (AMPS) Cellular, VHF-FM Digital Selective Calling (DSC), and Newcomb L-Band Satellite. The communications methods were evaluated according to the following criteria: coverage area, reliability, integrity, reporting interval, latency, and cost. Although all three communications methods worked, only DSC and Newcomb Satellite are well-suited for ADS implementation