GPS signal acquisition via compressive multichannel sampling

Abstract

In this paper, we propose an efficient acquisition scheme for GPS receivers. It is shown that GPS signals can be effectively sampled and detected using a bank of randomized correlators with much fewer chip-matched filters than those used in existing GPS signal acquisition algorithms. The latter use correlations with all possible shifted replicas of the satellite-specific C/A code and an exhaustive search for peaking signals over the delay-Doppler space. Our scheme is based on the recently proposed analog compressed sensing framework, and consists of a multichannel sampling structure with far fewer correlators.The compressive multichannel sampler outputs are linear combinations of a vector whose support tends to be sparse; by detecting its support one can identify the strongest satellite signals in the field of view and pinpoint the correct code-phase and Doppler shifts for finer resolution during tracking. The analysis in this paper demonstrates that GPS signals can be detected and acquired via the proposed structure at a lower cost in terms of number of correlations that need to be computed in the coarse acquisition phase, which in current GPS technology scales like the product of the number of all possible delays and Doppler shifts. In contrast, the required number of correlators in our compressive multichannel scheme scales as the number of satellites in the field of view of the device times the logarithm of number of delay-Doppler bins explored, as is typical for compressed sensing methods.

Weak GPS Acquisition Via Compressed Differential Detection Using Structured Measurement Matrix

“…The main aim of sparse signal processing based GPS signal acquisition is to identify the satellite visibility with lesser computation burden and this has been implemented in few literatures. Younina eldar et.al, [2] decomposes the GPS signal acquisition problem as a sparse spike representation of compressed measurement below the Nyquist rate. To enhance the Signal-to-Noise Ratio (SNR), T. L. Hansen et.al [3] proposed a rank deficient dictionary by choosing the rows of the measurement matrix as a random combination of the columns in the dictionary.…”

Signals that can be easily time-frequency synchronized from their ambiguity function

“…On the other hand, if f D is large, estimation problem of two parameters t d and f D becomes very difficult. Estimation of t d and f D is a fundamental problem in radar and sonar [6], [9]- [13], which appears in mobile communications [1], [2], GPS [3], [4], ultra wideband, and underwater acoustic communications [5].…”

GPS signal acquisition via folding and compressive sensing

“…In previous works [2]- [5], several techniques have been studied for PN code acquisition. In [2], the authors introduced a traditional PN code acquisition scheme by correlating the incoming signal with a bank of matched filters.…”