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A method and apparatus useful for determining the accumulated error in a user terminal dock in a satellite communications system. The satellite communications system includes a gateway, a satellite with a known position and known velocity, and a user terminal having a deskew buffer clocked by a user

A method and apparatus useful for determining the accumulated error in a user terminal dock in a satellite communications system. The satellite communications system includes a gateway, a satellite with a known position and known velocity, and a user terminal having a deskew buffer clocked by a user terminal clock. The method includes the steps of computing the one-way signal delay between the satellite and the user terminal, computing a desired deskew buffer delay based on the computed one-way signal delay and a predetermined maximum value of said one-way signal delay, and computing the accumulated error in the user terminal clock based on the desired deskew buffer delay and the actual deskew buffer delay.

대표청구항 ▼

[ What is claimed is:] [1.] In a communications system including a gateway, a satellite with a known position and known velocity, and a user terminal having a deskew buffer clocked by a user terminal clock, a system for determining the accumulated error in the user terminal clock over a predetermine

[ What is claimed is:] [1.] In a communications system including a gateway, a satellite with a known position and known velocity, and a user terminal having a deskew buffer clocked by a user terminal clock, a system for determining the accumulated error in the user terminal clock over a predetermined period, the system comprising:means for computing the one-way signal delay between the satellite and the user terminal based on a round-trip signal delay for signals sent from the gateway to the user terminal and back to the gateway, an actual deskew buffer delay imposed by the deskew buffer on the signals received by the user terminal, and the known position and known velocity of the satellite;means for computing a desired deskew buffer delay based on said one-way signal delay and a predetermined maximum value of said one-way signal delay; andmeans for computing the accumulated error in the user terminal clock based on said desired deskew buffer delay and said actual deskew buffer delay.