BPF算法（回溯粒子滤波），还包括判断粒子是否有效的子函数，以及其中用到的判断两条直线是否相交的函数（用来判断轨迹是否与墙壁相交）。- three particle filter algorithms(SIR,ASIR and BPF) for indoor pedestrian navigation.Also include a function for particle validation detection and a function to check if two lines i

线性二自由度车辆模型状态参数估计粒子滤波算法，车辆理想状态向量已和观测向量已给出-Linear two degrees of freedom vehicle model state estimation particle filter, vehicle and observation over the state vector has been given vector