用matlab实现GPS原理和接收机设计中卫星速度和位置坐标的计算。可以输入任意信号发射时间计算。-Realization of GPS principle and the calculation of satellite velocity and position coordinates in the design of the receiver using matlab. Can enter any signal emission time calculation.

读取sp3文件（P类型）中的精密星历，并用拉格朗日多项式九阶内插法计算卫星位置-Sp3 read the file (P type) in the ephemeris, and calculates the satellite position with a ninth order Lagrange polynomial interpolation