| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of quickly determining a position of a user terminal in a satellite communication system using one low-earth orbit satellite, using a characteristic of a communication signal therein. SOLUTION: A system and method is provided for determining the position of the user terminal (for example, a mobile wireless telephone) in the low-earth orbit satellite communication system 100. The system includes the user terminal 106, at least one satellite 104 with a known position and a known velocity, and a gateway 102 (i.e. terrestrial base station) communicated with the user terminal 106 via the satellite 104. The method includes a step 802 of determining a range parameter, and a step 806 of determining a range rate parameter. A range parameter indicates a distance between the satellite and the user terminal. A range rate parameter indicates a relative radial velocity between the satellite and the user terminal. The position of the user terminal on the Earth surface is determined based on the range parameter, the range rate parameter and the known position and the known velocity of the satellite (810). COPYRIGHT: (C)2008,JPO&INPIT
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