说明：  卡尔曼滤波Matlab实现线性系统估计,说白点就是对现在时刻的估计（可能是同时估计好几个变量）是取决于前一时刻估计误差和现在时刻的某个观测值。通过不断的预测和实测来修正自己的估计值，最后达到一个理想的平稳状态。
(Kalman filter Matlab for Linear system estimation,The estimation of the present moment (possibly several variables at the same time) depends on the estimation error of the previous moment and an observation at the present moment. The estimation is corrected by continuous prediction and measurement, and finally an ideal stationary state is achieved.)