Computationally efficient BeiDou B1C signal acquisition

Abstract

The Chinese BeiDou satellite navigation system provides global satellite coverage. The BeiDou system signals are very similar to signals of other global satellite systems. This makes adding support for the BeiDou system's signals more attractive for already existing receiver platforms. In this thesis, a computationally efficient method is proposed to acquire the BeiDou B1C signal for tracking. The B1I signal is acquired first, after which the B1C signal code phase is searched. Additionally, hot acquisition methods for the B1C signal are presented.

Before the proposed BeiDou methods are introduced, the basic principles of satellite systems are explained, including what constitutes a satellite system, the basic signal structures and the principles of the acquisition search. Later, the signal path inside a GNSS receiver is gone through together with the signal processing regarding acquisition and tracking.

The results of this thesis showed that the proposed method is more efficient both in terms of computational burden and acquisition time, when compared to direct B1C signal acquisition. The sensitivity of the proposed method is limited due to the noncoherent acquisition of the B1I signal, which is a consequence of the signal structure. The B1C code phase search has a negligible effect on the overall sensitivity. The hot acquisition methods used for refresh searches on the B1C signal offer ample sensitivity, while limiting the required processing.