An estimation method for fine-time synchronization of FH systems using the early-late filter technique

A novel method for estimating the fine-time error in a FHSS (frequency-hopped spread spectrum) FDMA satellite system system has been derived. This method, based on the early-late filter technique, uses three second order moments to provide a low-biased, but consistent, estimate of the time error. Results from an approximate analysis and from simulation show the good performance of the estimator. The estimator was found to be extremely robust in Rayleigh fading. In partial-band noise jamming, the estimator is consistent, although a larger value of L (hop periods) is needed to give performance equal to that for the unjammed case. For partial-band tone jamming, the estimator is inconsistent, although its standard deviation equals that for the unjammed case