Determining the MEMS INS Initial Heading Using Trajectory Matching for UAV Applications

To implement quick and accurate coarse alignment on a smart unmanned aerial vehicle (UAV), we propose an in-motion coarse heading alignment method using the low-cost microelectromechanical system (MEMS) inertial navigation system (INS) aided by the global navigation satellite system (GNSS) in this article. The principle of the proposed method is quite straightforward in that the initial heading can be achieved using trajectory matching: MEMS INS conducts INS mechanization to obtain a precise relative trajectory of UAV in a very short period; meanwhile, the absolute trajectory of UAV is provided by GNSS positioning. The heading can be achieved by comparing these two trajectory vectors. The proposed method is verified on the UAV under different representative motion modes. Results show that the initial heading of UAV can be determined accurately to 2.2° at a 95% confidence level within 4 s.