A system and method for determining the position of a user terminal (for example, a mobile wireless telephone) in a low-Earth orbit satellite communications system (100). The system includes a user terminal (106), at least one satellite (104) with a known position and velocity, and a gateway (102) (that is, a terrestrial base station) for communicating with the user terminal (106) through the satellite (104). The method includes the steps of determining a range parameter (802) and a range-rate parameter (806). A range parameter represents a distance between the satellite and the user terminal. A range-rate parameter represents a relative radial velocity between that satellite and the user terminal. The position of the user terminal on the Earth's surface is then determined (810) based on the range parameter, the range-rate parameter, and the known position and velocity of the satellite.