Hierarchical code acquisition for dual band GNSS receivers

Cross-Band Aided Code Acquisition in Dual-Band GNSS Receivers

“…For example, P f = 10 means that the entire UR processing (time and frequency) requires 10 times the code duration. According to (9), 200 frequency bins of 100 Hz are considered along with a sampling timing error equal to 0:0625 T c . The time search only is also reported as a reference while the case P f = 1 represents the performance obtained with no hardware limitations or constraints.…”

“…As already anticipated we process pilot codes only to perform code acquisition in the two bands, i.e., the signal component E1c in E1, and the signal component E5aQ in E5 [9]. In addition in E5 a single side band (SSB) processing scheme is considered [16]: accordingly, a frequency shift is performed over the entire received signal in order to convert in frequency the E5a component and by processing the resulting signal in a classical binary phase-shift keying (BPSK) fashion, strongly simplifying the baseband processing stage.…”

“…The structure of the Galileo E1 and E5 signals [8], where the pseudonoise DS-SS (direct-sequence spread-spectrum) code periods in the two bands can be related according to a specific rule in the time domain, allows in fact to implement a fast code acquisition approach able at the same time to improve acquisition performance and to guarantee limited complexity. In this work the information flows unidirectionally between the two bands and enables the reduction of the uncertainty region (UR) in one band when the signal in the other has already been acquired, as introduced in [9]. The approach can be generalized to cover the case of N band code acquisition, with N > 2, and also to bidirectional information flows.…”

“…These aspects are considered in the following. Expanding from [9], in this paper the performance analysis of the CBA techniques is carried out by introducing the overall mean acquisition time (OMAT) and analyzing the impact of the information exchange in speeding up the complete initial bi-dimensional time-frequency search. The numerical analysis demonstrates that the proposed approach allows to acquire the signals in both bands in an OMAT that is comparable to single band acquisition.…”

Galileo receiver for Mass Market Applications in the automotive area

“…Note that the signals use different code lengths and different data rates. The hierarchical code acquisition results in two major advantages: a reduced complexity, since a reduced number of acquisition tests have to be performed, and an increased performance due to the reduced acquisition time [6]. The digital signal processing -composed of the baseband processing, the channels and processors -is implemented on a rapid prototyping platform in a field programmable gate array (FPGA).…”