Spur Mitigation in High-Sensitivity GNSS Receivers

The presence of spurious tones in a Global Navigation Satellite Signal (GNSS) receiver´s RF and analog front-end signal spectrum leads it to compute receiver´s position erroneously. Addressing spurs is crucial in modern multiconstellation GNSS receivers as their wide bandwidth and coexistence on a shared chip or board with other radios and processors make them highly susceptible to corruption by dynamically varying spurs. Proposed here is a solution to mitigate a large number of spurs in GNSS receivers using a combination of limited number of frequency-tracked digital hardware filters, fast Fourier transform-based spur detectors, and a firmware algorithm predicting and weeding out potentially corrupt satellite measurements. Laboratory validation results from an experimental GNSS receiver in a CMOS system-on-chip are shown to demonstrate its effectiveness.