Indian Journal of Science and Technology

Abstract

Objectives: Radio frequency interference is major setback for précis estimation of position using GPS receivers in the real time environment. An approach to handle such situations is the implementation of receiver using cutting edge signal processing technologies. Methods/Statistical Analysis: A strong signal from other communication channels and narrow band pulse signal are the major components of interference for GPS signals. Acquisition is primary and important signal processing step in GPS receiver. The performance of a GPS receiver depends on the acquisition process in the presence of interference. In this paper an acquisition method using the Discrete Wavelet Transform is proposed to mitigate the interference and to measure the acquisition parameters. Findings: Conventional GPS receiver uses the Fast Fourier Transform (FFT) to perform convolution in the acquisition process. This method is unable to acquire the GPS signal in the presence of interference. The Discrete Wavelet Transform decomposition and appropriate thresholding method for the convolution in the acquisition process permit the algorithm to demonstrate the successful mitigation of Continuous Wave Interference (CWI). Performance of the conventional and proposed acquisition algorithms are compared based on statistical parameter correlation ratio and maximum peak measured. Results show that the proposed algorithm DWT based acquisition performed well than the conventional method of acquisition.
Keywords: Acquisition, CWI, DWT, GPS, Thresholding