The Automatic Identification System (AIS) receiver on board the main satellite of the TianTuo-3 constellation, LvLiang-1, is a new generation of AIS receiver. Having partly solved the signal conflict problems and with larger coverage over the ground, the AIS receiver on board TianTuo-3 greatly improves the signal detection ability. The data received by the AIS receiver during the TianTuo-3 debugging stage is employed for detailed analysis in this paper. Results include: TianTuo-3 implements four-frequency detection at the same time, and a time-flag is inserted into the received AIS data, a small portion of Class A vessels (at least 1480) have been equipped with AIS sending the long range AIS broadcast message with two new frequency channels and the hourly averaged count of the message received by TianTuo-3’s AIS is between 1500 ~ 2500. This AIS receiver is capable of real-time tracking a single vessel. In conclusion, the TianTuo-3 space-based AIS receiver is capable of continuously receiving AIS messages sent by global maritime vessels.

In shipborne Transfer Alignment (TA) applications, partial observability is one of the most important factors limiting convergence velocity. This paper proposes a new method of attributing weak observable states and lever-arm variables to a group of constraints in order to improve the observability of TA model. This yields the so-called Constrained Transfer Alignment (CTA) model which is uniformly observable even under zero-manoeuvre conditions. Within this framework, the Moving Horizon Estimation (MHE) and its stability analysis are also addressed. Finally, comparative simulation results are given to demonstrate the advantages of the proposed approach.