Patent ID: 6014404
Filing Date: 2000-01-11
Classification: G01S,H04B

Abstract:
A method for independently reducing acquisition thresholds and tracking spread spectrum codes received in orbit by a receiver accessing an orbital navigator, wherein the receiver includes a phase loop and a code loop, the method comprising the steps of:receiving, in the receiver from the orbital navigator, a fine velocity aid required for normal assisted acquisition, enabling the receiver to receive all signals with a signal-to-noise (C/No) ratio when C/No>(C/No).sub.3, where (C/No).sub.3 is a reception threshold in normal assisted acquisition mode:tracking, using the code loop, pseudo-random codes;correcting an error between real and calculated velocities by using the fine velocity aid,searching for a code phase based on a phase prediction maintained by the fine velocity aid provided by the orbital navigator; andlowering thresholds of the pseudo-random codes to a value (C/No).sub.avf, wherein (C/No).sub.avf is a reception threshold of pseudo-random codes in acquisition mode assisted by the fine velocity aid provided by the orbital navigator.