The design concept of digital intermediate frequency is widely used in modern TACAN air borne equipment, and Kalman filter theory, as the most mature and widely used control and prediction theory in current engineering, can be combined to achieve the filtering of TACAN baseband pulse signal, to improve the ultimate goal of measurement accuracy. Starting from the practical engineering application, through the derivation of the pulse envelope mathematical model, the construction of discrete Kalman filter state space equation, using Matlab simulation of Kalman filter prediction, update process, complete the design algorithm verification, improve baseband SNR.