Sub-Nyquist Sampling based Low Complexity Fast AltBOC Acquisition

Due to secondary code and AltBOC modulation, the primary code acquisition of the Galileo E5 signal can be complicated and requires additional hardware resources and algorithmic complexity in a receiver. In this paper, we propose a fast primary code acquisition technique for the Galileo E5 signal to reduce both hardware and algorithm complexities, while achieving a similar or better performance in receiver operating characteristic (ROC) and mean acquisition time (MAT), respectively. The proposed technique employs a sub-Nyquist sampling scheme followed by a sample compression scheme to cause a complete aliasing between the spectra of E5a and E5b signals to minimize the signal bandwidth and to reduce the number of code phase hypothesis to search. We demonstrate with numerous Monte Carlo simulations that the MAT of the proposed technique is about a half of the conventional AltBOC acquisition techniques.