Optimal policy of pitch-hold phase for mine detection of UAV based on mixed-integer linear programming

An optimization problem is formulated to maximize the coverage of the detection area for a fixed wing unmanned aerial vehicle (UAV), which performs a landmine detection mission. The UAV has mine detection devices including magnetic field sensors and chemical sensors. Due to the characteristics of the detection sensors, the UAV should fly at a certain altitude above the ground while following the terrain to perform accurate mine detection. Also, the UAV is required to maintain the pitch angle around the trim value when changing the altitude. Consequently, the altitude change rate of the UAV is limited during the mission. To maximize the mine detection capability within the limit, in this study, the entire flight interval is divided into the intervals on which the mines can be detected accurately and the intervals on which accurate detection is not possible. Logical variables are introduced to indicate the satisfaction of the requirements for accurate detection. Constraints on the logical variables are transformed into a set of linear inequalities containing continuous variables and binary integer variables. Finally, the optimization problem is formulated as a mixed-integer linear programming problem. The effectiveness of the proposed method is demonstrated through numerical simulation.