The increased importance of maritime transport and operations leads to more congested sea lanes. Denser sea routes increase the probability of accidents respectively collisions. The major factors that lead to the accidents on water are human error (communication, level of crew’s experience, fatigue etc.), marine traffic environment, ship and platform (structural) condition, and incompleteness/lack of properly implemented waterborne transportation safety supporting systems. Further increasing dangers like unexpected sea state conditions mean additional risks for the vessels/platforms with not only financial consequences but also loss of human lives and damage to the environment.The proposed project will provide an additional pair of “eyes” to maritime operators called the Active & Passive Sensor NETwork (APS-NET). A prototype of a flexible, multi-purpose surveillance system will be developed and tested under real life conditions. The APS-NET system provides the operator with an accurate picture that can’t be matched with any single commercial observation system today.APS-NET consists of various parts; the active sensor system, observing at close distances at 360 degrees with unprecedented high resolution, and the passive sensor system, detecting objects at greater distances by radio emissions and triangulation-like processes. Thereby it reduces numerous maritime risks such as accidental collisions with ships, rouge waves, icebergs, and so forth.The APS-NET is a network of several active and passive parts. The dynamic network structure allows shared processing between different sensors and central core processing units. Also information from other sensors onboard ships, platforms and elsewhere is shared with the APS-NET observations to increase the situational awareness of maritime operators.