Abstract: The Automatic Identification System(AIS),which is imposed by the International Maritime Organization(IMO),is a maritime safety and vessel traffic system．For security,the AIS-equipped ships broadcast position reports and short messages with information about the ship and the voyage that could be received by other ships and shore-based stations．AIS uses self-organizing TDMA(SOTDMA)for scheduled repetitive transmissions from an autonomous station．But the conflicts are difficult to escape．In the paper,once the conflicts appear,the technology of blind source separation will be introduced into AIS．It could separate each message from the coinciding transmissions,avoid messages losing,and improve the detection probability.

Key words: AIS,Detection probability,Blind source separation