Abstract: This paper deals with flow measurements based on ultrasonic time-of-flight estimation.The Unscented Kalman Filter（UKF） is proposed to deal with ultrasonic echo signals and echo signal envelope is acquired.Then the parameters of the envelope are used as the processed state vector.This paper improves the operation of UKF process based on the characteristics of flow measurement，and gives the condition of beginning and end of UKF iteration.Finally，the performance of UKF and its convergence rate are simulated，which proves its reliability，effectiveness and easiness to achieve along with advantages compared with the previous ones.

摘要： 将UKF滤波用于超声波流量测量，使用UKF滤波算法来处理超声波回波信号，得到回波信号的包络线，并且将包络模型的参数作为UKF处理的状态向量。根据流量测量的特点改进了UKF滤波运算过程，给出了UKF迭代开始和结束的条件。最后在Matlab上仿真UKF的性能及收敛速度，证明UKF是有效的和容易实现的。