Investigation on the Effect of the B1I Navigation Receiver Under Multifrequency Interference

At present, the research on the tracking performance of navigation receivers is based on the conditions of single-frequency interference, however, the space electromagnetic environment is complicated, and so it is necessary to study the effect of the navigation receiver under multifrequency interference. Through the analysis of the blocking interference mechanism of the navigation receiver and the mathematical model of the tracking loop, the effect model under in-band and out-of-band multifrequency interference is established, when the satellite tracking is missing. The Beidou navigation receiver is used as the experiment object to build a multifrequency interference effect experiment platform, and the carrier-to-noise ratio ($C/N_0$) threshold is used as the criterion for the satellite tracking missing, Finally, the model is verified with the experimental data, the error of the model under tri-frequency out-of-band interference exceeds 3 dB. For reducing the model error, the corrected model is proposed, and the corrected model errors are less than 1 dB. The model is helpful to predict the satellite signal status in the navigation receiver under complex electromagnetic environments.