Time-Frequency Based Intentional Interference Suppression Techniques in GNSS Receivers

There are some scenarios where GNSS receiver could be completely jammed due to interference sources such as in-car jammers that degrade positioning performance proportional to the distance. In that case, by using pre-correlation interference excisers, it is possible to increase the interference immunity of the receiver. This paper concerns two interference suppression methods namely Short Time Fourier Transform (STFT) and Short Time Fractional Fourier Transform (STFrFT) against in-car GNSS chirp jammer. To the best of our knowledge, FrFT is used for the first time in GNSS domain as an interference cancellation method. Both methods use blanking as an excision method in the transform domain. For the sake of fairness in the comparison of both methods and in order to have equal time resolution, same window size is used. Our analysis showed that STFrFT outperformed STFT by around 1.1 dB tracking sensitivity gain in the presence of single component chirp jammer signal.