Unmanned aerial vehicle (UAV) technology is widely used in transportation, in the process of UAV for satellite navigation and positioning, according to the broadcast ephemeris parameters according to the BeiDou Navigation Satellite System Signal In Space Interface Control Document, in the formula to calculate the satellite coordinates, tedious calculation process, means in the process of flight need longer operation time and higher power consumption. Lagrange interpolation algorithm is usually used to reduce the amount of computation, but it is prone to Runge phenomenon. In order to eliminate the rune phenomenon, the interpolation algorithm is studied and the sliding interpolation algorithm for equidistant nodes is proposed. The broadcast calendar of BeiDou satellite is used as experimental data to calculate the 3d coordinates of the satellite. The experimental results show that the algorithm can meet the accuracy requirements and eliminate the Runge phenomenon.