Constrained-trajectory based GPS/INS integration for reliable position and attitude determination

In this paper, we propose a constrained method to incorporate a priori flight trajectory information into the GPS derived navigation solutions which will ensure the availability and reliability of the GPS solutions even when the number of satellites reduces to less than four. Moreover, we fuse the navigation solutions derived from the proposed constrained method with those obtained from the inertial navigation system (INS) in order to fully gain their complementary features of both systems. The simulation results show that the proposed scheme provides the complete 6 degree-of-freedom (DoF) state at high data rate with only two satellites required.