The satellite has an advanced receiver on board that picks up the signals ships AIS boxes transmitt

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The Danish satellite AAUSAT3 which was launched from a space station in India for13 days ago, works perfectly. The satellite passes over the poles every hour and a half, and it gives a much better overvgning of vessel traffic than before.
The satellite has an advanced receiver on board that picks up the signals ships AIS boxes transmitting f seconds usf holland tracking on the course, speed and position. The satellite advanced technique makes it possible to detect ships that previously would not be seen Each ship listen on AIS frequencies and udvlger time of its own transmissions, but on account of the Earth's curvature, a ship only pick up signals up distances up to 60-100 km. That's plenty to ship systems mocks another. But the ships can not see each other on account of curvature of the Earth, usf holland tracking s can AIS box does not see what AIS cues that are in use. The risk therefore usf holland tracking to choose a time that is already used a little longer away. A single AIS receiver mounted on a satellite in approximately 800 kilometers height can generally not distinguish two ships apart if the ships are on the mouth of another, said Omar Frits Eriksson. Head and svagstrmsingenir from Sfartsstyrelsen. But AAUSAT3 have just a very flexible SDR-based AIS receiver on board that can exploit the fact that if the vessels are far enough apart, their Doppler shift VRE differently, as seen from the satellite says Eriksson. Therefore, in many cases receive transmissions that are broadcast on the same frequency and at the same time and on the basis of the Doppler effect to separate them. AAUSAT3 is a fllesprojekt between Sfartsstyrelsen and Aalborg University. Source: Ingeniren