APS-NET is...
A multi-sensor surveillance system that provides vessels and maritime infrastructures with accurate information about (moving) objects surrounding them and sea variations. This greatly improves the safety of sea transport and offshore operations by reducing the risks of accidents and piracy.
The system can either be used as a primary surveillance and monitoring system or as a valuable addition to conventional surveillance techniques to increase accuracy resolution (both spatial and temporal) and usability in various weather and sea conditions.