A Comparison of Optimized Mitigation Techniques for Swept-frequency Jammers

This paper proposes an optimization of the characteristic parameters that define four architectures of adaptive notch filters, used to mitigate the effect of swept-frequency (chirp) jamming signals at the input of a GNSS receiver. The optimization is based on a performance metric computed at the acquisition stage of the receiver that represents a measure of the ratio between the peak of the cross-ambiguity function computed in acquisition and the noise floor. The optimization is intended to find the parameters of the adaptive notch filter architectures that minimize the loss in terms of this metric with respect to the interference-free case. The paper discusses the optimization of the parameters for the four considered architectures. The optimization process is performed under different working conditions, so as to highlight the sensitivity of the parameters to the changes of the operational scenarios. This paper presents the results of an analysis which is meant to evolve in a more complete picture of the optimal performance achievable by an adaptive notch filter in the presence of chirp jamming signals.