Investigation on In-band Interference Effect and Out-of-band Interference Mechanism of B1I Navigation Receiver

Aiming at the problem that the Beidou B1I navi¬gation receiver is susceptible to continuous-wave interfer¬ence (CWI), it is of great significance to investigate the interference effect and mechanism of the B1I navigation receiver. With the threshold of carrier-to-noise ratio (C/N0) as the criterion of satellite tracking missing, the CWI injection experiment is conducted on a kind of B1I navigation receiver. The results indicate that the power spectrum of the satellite signal affects the CWI's ability to interfere with each satellite. Then, a prediction model of satellite tracking loss under dual-frequency CWI is proposed, and the accuracy of the model is verified through experiments. The experiment results demonstrate that the power combination between the dual-frequency CWI is negatively correlated, and the error of this model is less than 2 dB. Finally, the sensitive frequency bands of the navigation receiver under out-of-band CWI are obtained through experiments. It is confirmed by theoretical and simulation analysis that the mixer is the main non-linear circuit generating these sensitive frequency bands. Furthermore, improving the selectivity of the radio frequency (RF) front-end circuit can enhance the performance of anti out-of-band interference.