Abstract: As far as the target tracking system is concerned,if the measurement units applied in data fusion,such as location or velocity,have systematic error,the Least-square differential smooth method can be used to filter and detect the systematic error.Since the processing precision of differential smooth method is low,a method of integral matched filter is proposed.The(mathematical) deduction testifies that this method can obtain more precise systematic error(estimation) than the differential smooth method.And the simulation result also verifies this(conclusion).