Spoofing Mitigation Using Double Stationary Wavelet Transform in Civil GPS Receivers

In this paper, the Wavelet Transform (WT) is used to eliminate the influence of spoofing on the stationary Global Positioning System (GPS) receivers. Having no access to the authentic data, signal processing is only applied to the received spoofing signals. Pseudo-range is one of the most important influenced parameters under spoofing attack. Therefore, by reducing its deviations, spoofing reduction is possible. In this way, the pseudo-range difference between two observations is passed to the Statistic Wavelet Transform (SWT) at the first level. By de-noising in the next step and omission of noise, pseudo-range deviations due to a spoofing attack can be extracted. After that, measured pseudo-range of received signal is corrected. In the next step, the SWT is applied to the position coordinates. In this point, other irrational deviations because of spoofing threat can be compensated. For validation of the suggested algorithm, four different data sets are investigated. By applying bior 3.7 at level 3 and rbio 4.4 at level 9 as the first and the second WT respectively, we could mitigate spoofing more than 81% within a tolerance of 10% and an average of 86%. The test results show that the proposed technique supremely improves the performance of the GPS receiver and attenuates the effects of spoofing.