Epoch Time Estimation of the Frequency Hopping Signal

The paper investigates the epoch time parameters estimation of the frequency hopping FH signals, which are of major interest in most of the recent commercial applications. Two types of estimation models has been simulated and examined in this work. The first is the single-hop autocorrelation (SHAC) processor. It is considered as a means of estimating the epoch time of the FH signal in the presence of AWGN. The second is the expanded multiple stages-frequency hoppinghop rate detector (EMS-FH-HRD). The later has been modified in this work from the hopping rate detector, which detects only the presence of the FH signal, and operated in noisy environment. These two were independent of the hopping frequency pattern and the carrier phase (the sequence of the hopping frequencies is totally unknown. These models have been simulated using Matlab version 6.5 and examined in AWGN environment. The results show that both SHAC and EMS-FH-HRD give acceptable results. The percentage of error increases as the SNR decreases. Furthermore, the EMS-FH-HRD gives better results than that of the SHAC and have no ambiguity as that SHAC at certain conditions. The advantage of EMS-FH-HRD epoch time estimator over SHAC is that it could estimate the normalized epoch time with very low percentage error and at even more condition where the SHAC fails.