Adaptive Data Length Method for GPS Signal Acquisition in Weak to Strong Fading Conditions

Arif Hussain,Jahangeer Badar Soomro,Syed Sabir Hussain Bukhari,Arslan Ahmed,Hina Magsi,Jong-Suk Ro

doi:10.3390/electronics10141735

Arif Hussain, Jahangeer Badar Soomro + Show 4 more

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https://doi.org/10.3390/electronics10141735

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Journal: Electronics	Publication Date: Jul 19, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: Sukkur IBA University, Chung-Ang University

Abstract

Satellite-based navigation is an essential part of all the technology-dependent applications, such as road transport, cell phones, the medical field, aviation or the shipping industry, etc. The performance of the navigation systems depends upon how quickly they can acquire and process the received signals for positioning solutions. However, in dense urban or indoor environments, signal acquisition can be a challenging task due to fading as a result of multipath and/or interference. This paper presents post-processing acquisition results on Global Positioning System (GPS) signals to study the relationship between data lengths used for signal acquisition and the achieved signal power using a Fast Fourier Transform (FFT)-based circular correlation method. Based on this study, the detection performance of the FFT-based method has also been analyzed by intentionally degrading the signal power levels. A new Adaptive Data length (ADL) method for acquisition has been proposed in this paper, which can be used for speeding up the acquisition process and uses adaptive data lengths rather than fixed data lengths. The ADL method works by estimating the threshold level based on the noise present in the signal and then comparing it with the signal power levels. Less difference between the threshold level and signal power level means less data length will be used while more difference means that more data length will be used for acquisition. The proposed algorithm can be used in commercially available receivers for adopting to an adaptive acquisition process for increased efficiency.

Highlights

Introduction published maps and institutional affilA large number of the world population lives in urban areas due to increased availability of facilities and ease of access to resources
The paper investigated the acquisition process as a whole and presented the results on how the acquisition in a Global Positioning System (GPS) receiver can be affected by weak to strong fading levels, which reduces the Signal-to-Noise Ratio (SNR) of the received signal and can make acquisition quite challenging in dense urban environments
Three different cases were investigated for this purpose, i.e., 5 dB, 10 dB and 15 dB fading, and it was found that fixed data lengths used by the receivers are not an optimal solution to use in weak to moderate signal fading

Summary

Introduction

A large number of the world population lives in urban areas due to increased availability of facilities and ease of access to resources. An accurate and reliable positioning service in urban areas by satellite-based navigation systems is essentially important for hundreds of civilian and military applications [1,2,3,4,5,6,7]. There are four independent Global Navigation Satellite Systems (GNSS), including American GPS, Russian GLONASS, European Galileo and Chinese BeiDou Navigation System, providing an easy, efficient and cost-effective way to determine the location, time, and velocity anywhere around the globe [8,9,10].

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