Novel partial correlation method algorithm for acquisition of GNSS tiered signals

This paper presents a new modified Single Block Zero-Padding (mSBZP) Partial Correlation Method (PCM) Parallel Code Search (PCS) algorithm for effective acquisition of weak GNSS tiered signal using coherent processing of its secondary code (SC) component. Two problems are discussed: acquisition of primary codes with a longer period using FFT blocks of limited length, and the utilization of PCS in the presence of SC bit transition. The PCM and SC bit transition forms parasitic fragments in the Cross-Ambiguity-Function (CAF) to devaluate signal detection performance. A novel analysis of this mechanism and its impact is presented. A novel mSBZP-PCM-PCS algorithm is proposed, which does not degrade the CAF. Then, the algorithm is combined with SC bit transition removal schema and sequential search to construct an estimator for weak tiered signal acquisition. The performance of the method is demonstrated by analysis and computer simulation using Galileo E1C and GPS L1C-P signals.