Aiming at solving the probloms such as the quantity of experimentation data ，the rapid rate of data，artificial and inefficiency judge data in the process of gps equipment of Weapons Positioning error computation,this paper designs a set of positioning data acquisition and processing system. Based on medium-long baseline GPS kinematic positioning model and the theory of classic fading Kalman filter, a modified fading factor vector is proposed. Different widths of sliding windows are used toobtain a series of parallel filters. The weight factor of covariance is decided by the residuals of every filter. The modified fading Kalman filter is more effective and sensitive than classic Kalman filter. Various experiments are made to test the performance of this method. The results show the precision of long-baseline GPS kinematic positioning is improved. This system implements Positioning data acquisition，displaying ，Positioning accuracy calculating and the original data storage ,which improves experimenting process.