The Automatic Identification System (AIS) is a maritime VHF communication system that provides information about ship identification, location, course, speed, etc. to other ships and ground stations with goal of assisting with ship collision avoidance, security and vehicle tracking [1]. Ground stations have limited range and therefore are not only unable to gather information about ships far from coast, but require large number of such stations to cover the entire coastline. AIS messages are transmitted in two channels – A, 161.975MHz and B, 162.025, using 9.6 kbps GMSK modulation over 25 or 12.5 kHz channels. To avoid message collisions a self-organizing time division multiple access (SOTDMA) scheme is used. The system uses the concept of 1 minute long time frames consisting of 2250 message slots [2]. A satellite based AIS receiver faces additional challenges when dealing not only with reduced signal-to-noise ratio, Doppler shift and environmental conditions, but also the possibility of packet collision. As TDMA of AIS signals work on a local level but satellites have large coverage area, there is a possibility of ships that are not in view of each other to be both transmitting AIS messages on the same time slot. Collisions could also be caused by different path lengths making the adjacent time slot messages overlap. Although suck situations would be rare in open seas, in areas with larger amounts of maritime traffic, which are of greater interest, the loss of data could be significant [3]. During the last decade there has been a push to implement space-based AIS receivers. Using nano-satellites for AIS monitoring provide data for vessel traffic in distant off-coast areas and give an insight into the collision of AIS messages in high-density traffic areas. One of the problems is to build the payload for such satellite – flexible and efficient AIS receiver system that meets low energy, size, and weight requirements.