Performance Comparison of FLL Adaptive Notch Filters to Counter GNSS Jamming

Adaptive notch filters in general, and frequency lock loop-equivalent adaptive notch filters in particular, have been shown to be an effective solution to counteract jamming signals. Much effort has been spent at analyzing their adaptive capability, while detection approaches in charge of activating/deactivating the filter have not been properly addressed. This paper presents two new detection strategies, namely discriminator-based and output-input power ratio-based, suitable to be applied to FLL-equivalent ANFs. The performance evaluation for several interference-to-noise ratio conditions demostrates their suitability to be combined with such kind of filters and their effectiveness in mitigating jamming signals.