An Improved Practical Anti-jamming Technique for GNSS Receivers Based ADP in Frequency Domain

Anti-jamming techniques have been widely researched to enhance the reliability and effectivity of Global Navigation Satellite System (GNSS). Amplitude Domain Processing (ADP) is an anti-jamming method base on Locally Most Powerful (LMP) detection theory. While it works efficiently when dealing with some relatively simple interferences, such as one or two continuous wave interferences, it has a limitation when submitted to multiple interference scenarios. Then, some later researches prove that using ADP in frequency domain (FADP) would give a more superior performance, and put forward a simple global framework of this method. However, there are still several important specific problems needing to be solved before FADP's being brought into practice, as the spectrum leakage and malignant distribution of the frequency domain statistical data would surely degrade the performance of the method or even invalidate it. In this paper, an improved anti-jamming technique based on FADP is proposed, which is more robust for practical consideration. Firstly, a windowed FFT is used to inhibit the spectrum leakage and signal distortion, as well as the pattern of overlap-adding is chosen to minimize the degradation of the SNR. Then, along with the analysis of the differences between statistical characteristics of the time-domain waveform and spectrum data, a specialized mathematical function of ADP is designed, responding to the wide range and malignant distribution of spectrum data. Meanwhile, a simplification of the procedures also eliminates the need of mutual transformation between Cartesian coordinates and polar coordinates, saving the computation and storage resources in some way. Simulation results demonstrate that the proposed improved FADP method performs more efficaciously in realistic situation than the original one.