Analysis of the global position system acquisition process in the presence of interference

Abstract

The objective of the acquisition process is to provide a rough estimate of Doppler and code delay of the received signal. The correlation process with a local replica generated by the receiver may have a peak that may cross the acquisition threshold. One of the threats that could interrupt such procedure is the presence of interfering signals which may severely cause an incorrect or no correlation peak during the acquisition process. To this end, this study investigates the performance of the global position system (GPS) signal acquisition process in the presence of different types of interfering signals such as: continuous wave interference, narrowband interference, partial band interference, broadband interference, matched spectrum interference and pulse interference. A novel classification to the interfering signals is presented. This classification is divided into two categories based on the interference contribution to the acquisition's output mean or variance values. Novel expressions of both false alarm and detection probabilities in the presence of noise along with different types of interfering signals are mathematically formulated. The comparison among the interfering signals based on the receiver operation characteristic is also performed. The impact of both coherent integration time and the phase shift between the GPS and the interfering signals on the acquisition performance is analysed.