A trajectory optimization method for reducing magnetic disturbance of an internal combustion engine powered unmanned aerial vehicle

Magnetic disturbance generated by an unmanned aerial vehicle (UAV) is the leading cause of magnetic airborne detector (MAD) misjudgment in UAV underwater magnetic survey. Different from traditional schemes, a new method of reducing magnetic disturbance from the perspective of trajectory optimization is proposed in this paper. First, the magnetic disturbance on UAV is analyzed and classified. Then the magnetic disturbance model of airframe coupled with 6 degrees of freedom (DoF) UAV dynamic model is established. Second, this paper proposes a mechanism model of lithium battery magnetic field. Third, the optimal control problem and its solution framework are constructed. The hp-adaptive Radau pseudospectral method and optimization of lithium battery setting angle are proposed to solve this optimal control problem. Objective function linearization and model-based variable reduction strategy are proposed to improve the method and help the results converge. Finally, aeromagnetic survey scenes of “point-to-point” and “regional coverage” are simulated. The results showed that the impact of UAV magnetic disturbance at MAD could be effectively reduced.