A Generalized Anti-Interference Low-Ambiguity Dual-Frequency Multiplexing Modulation Based on the Frequency-Hopping Technique

To improve the anti-interference performance and mitigate the autocorrelation function (ACF) ambiguity of dual-frequency multiplexing modulation, we propose a new type of modulation: frequency-hopping alternated binary offset carrier (FH-AltBOC) modulation based on the frequency-hopping technique. The new modulation is generalized and includes AltBOC modulation, so it inherits the advantages of AltBOC modulation while also exhibiting new properties, such as low ambiguity, low probability of intercept, and better anti-narrowband interference and multipath performance. We first establish the mathematical model, derive the autocorrelation function (ACF) and the power spectrum density (PSD) for the FH-AltBOC modulation. Next, we propose optimal parameters and present a generation and detection scheme. The acquisition time and acquisition complexity of the receiving process for the proposed FH-AltBOC signal are the same as those of the AltBOC signal with the same main-lobe bandwidth (MLB). Finally, we evaluate the performance of several representative FH-AltBOC and AltBOC signals. The results show that FH-AltBOC(24:1:1,1) has the lowest ACF ambiguity, the best anti-interception, anti-narrowband interference, and multipath performance among the considered signals. FH-AltBOC(24:1:6,1) realizes higher tracking accuracy, lower ACF ambiguity, and better anti-narrowband interference and multipath performance than AltBOC(15,10). FH-AltBOC can serve as a new signal design paradigm for global navigation satellite systems (GNSS) and GNSS-like systems.