Sub-Band AGC-Based Interference Mitigation

Interference signals significantly affect the performance of global navigation satellite system (GNSS) receivers. Therefore, different mitigation methods have been proposed in the literature with different mitigation performances according to the type of interference. One method proven more effective against several interference types is the high-rate DFT-based data manipulator (HDDM) pulse blanking (PB). However, it performs poorly in the case of wide-band noise signals. To overcome these limitations, we propose a new HDDM structure where the interference is attenuated instead of removed. It corresponds to automatic gain control (AGC) applied to each fast Fourier transform (FFT) output in the HDDM: the new version is called HDDM-AGC. This paper presents a hardware implementation of the HDDM-AGC algorithm and its evaluation in an exemplary hardware configuration. Results with interference show, in most cases, the same or improved performance as the HDDM-PB. The significant improvements can be seen in continuous interference as wide-band noise or continuous-wave (CW) signals. Only with the frequency hopper and pulsed interferences, we see inferior results than to HDDM-PB.