四轴飞行器飞控程序，串级PID，外环PI内环PID，四元数互补滤波，辅助三角函数姿态解算。-Four-axis aircraft flight control procedures, Cascade PID, PI outer inner PID, quaternion complementary filter, auxiliary trigonometric attitude solution.

Including quaternion various calculations, Consider shadow rain attenuation and multipath effects Based on SVPWM three-level inverter matlab simulation.