Memory‐based two‐dimensional‐parallel differential matched filter correlator for global navigation satellite system code acquisition

Abstract

This study presents a code acquisition architecture for a global navigation satellite system (GNSS). The proposed scheme aim to reduce buffer resource required without reducing the number of code, frequency and satellite bins. Therefore the GNSS signal has no information loss. The code acquisition process in a GNSS attempts to find the code phase of a satellite signal, and it includes three procedures: coherent integration (CI), correlation and in CI. The proposed code acquisition architecture provides a lower operation count for correlation with reduced memory consumption. Firstly, the memory in CI and the shift register in the correlator are integrated by changing the operation sequence of CI and correlation. Thus, half of the memory in CI can be removed, and the shift register becomes the sharing buffer for both correlation and CI. Secondly, the addition count in the correlation is reduced by combining a parallel differential matched filter (PDMF) with a two-dimensional (2D) architecture to form a memory-based 2D-PDMF correlator. Finally, changing the sample sequence before integration reduces the memory of in CI. Compared with conventional code acquisition, the proposed design can reduce register consumption by 80% and addition count by 60% operation count for correlation and 50% memory consumption of incoherent integration.

An Optimization Synchronization Algorithm for TDDM Signal

“…The received signal ( ) is multiplied by the new local signals 0 ( ) and ( ), whose results are given by (11) and (12). Thus, the accumulative totals are given by (13) and (14):…”

“…In [11], the authors provided a detailed analysis of the significance of the cell-correlation phenomenon in MF correlates for the two widely used signal families in GNSS, namely, BPSK and BOC; next, the theoretical analysis was validated by Monte Carlo simulations. In [12], the code acquisition architecture for GNSS was presented to reduce the buffer resource required without reducing the numbers of code, frequency, and satellite bins. In [13], the authors proposed to reconstruct the correlation results of DBZP to improve the detection performance of the previously published double-block zero-padding (DBZP) method for weak GNSS long PN code signals.…”

Data and pilot optimised combining method for new composite global navigation satellite system signal acquisition

“…Table 5 shows the comparison among different methods in terms of complex multiplication, complex addition and comparison numbers. As in [29], the complexity comparison in the practical case is given as well as complexity expressions without considering the complexity caused by the Doppler removal. T coh for GPS L5 is 1 ms.…”

FFT Splitting for Improved FPGA-Based Acquisition of GNSS Signals

“…Among different methods, there is the basic serial search (SS) [16], there are one-dimensional parallel searches such as the parallel frequency search (PFS) and the PCS [16], [17,Chap. 2], and there are two-dimensional parallel searches such as the DBZP method [11,12] (which is an extension of the PFS) or the methods proposed in [18,19]. The parallel code search method seems to be among the most attractive methods for the acquisition of modern signals, because it can compensate the code Doppler (especially important with signals having a high chipping rate and with weak signals requiring a long integration) whereas some other methods (such as those based on the PFS) cannot compensate it [20], and onedimensional parallel methods are less complex to implement than two-dimensional parallel methods.…”