IMM-three

代码说明：

  基于三个模型的目标跟踪，中心角速度为0.偏移角速度固定。能够解决轨迹为非线性的目标的跟踪。自带轨迹。(Target tracking based on the three models, the central angular velocity is 0. Offsets the fixed angular velocity. Can solve the trajectory tracking of nonlinear target. Own trajectory.)