Signal environment mapping of the Automatic Identification System frequencies from space

This paper presents received signal strength data recorded by the NORAIS Receiver on the four VHF channels allocated to the use of the Automatic Identification System (AIS). The NORAIS Receiver operated on-board the Columbus module of the International Space Station from June 2010 to February 2015. The data shows that a space-based AIS receiver must handle transient strong signals from land-based interference and that the effectiveness of the two long range AIS channels recently allocated is severely reduced in select areas due to land based interference.