扩展卡尔曼滤波，非线性EKF的仿真与用法。描述了两个非线性方程x=0.5 x + (25 * x / (1 + x^2)) + 8 * cos(1.2*(t-1)) y = (x^2 / 20)的EKF的用法。简单实用，有备注。对于卡尔曼滤波初学者很有用。-Extended Kalman filter, nonlinear EKF simulation and usage. Describes two nonlinear equations x = 0.5 x+ (25* x/(1+ x ^ 2))+ 8* cos (1.2* (t-1))　y = (x ^ 2/20) of EKF usage. Simple and practical notes. For the Kalman filter useful for beginners.