Abstract: A method based on grey theory is proposed to solve the problem of unmanned moving target positioning caused by weak signals or strong interference in the BeiDou Navigation System (BDS). The method uses the grey model GM(1,1) to establish a coordinate prediction model based on the historical discrete data of unmanned moving targets, and verifies the validity of the model using measured data. The accuracy of the grey model in positioning prediction is quantitatively analyzed through simulation experiments, and its error probability is calculated. Compared with traditional positioning methods, this model requires less data and is computationally convenient, with lower complexity.