A DME Interference Signal Identification and Mitigation Approach based on Gaussian Mixture Model used for BDS B2a Receivers

Distance Measuring Equipment (DME) signal is a typical pulse interference to civil B2a signal of the BeiDou Navigation Satellite System (BDS). To guarantee the robustness of the receivers under DME interference, it is necessary to apply interference mitigation algorithms. A DME interference signal identification and mitigation approach based on Gaussian Mixture Model (GMM) is proposed in this paper. The Expectation- Maximization (EM) algorithm is used to estimate the GMM parameters, which mainly includes the variances and mixture weights of each Gaussian distribution. An outdoor experiment is conducted to collect B2a signals in a real DME interference environment around a DME station close to the Beijing Capital International Airport. The results show that the probability density function of the collected data is well fitted by the GMM. By applying the proposed GMM-based approach, the interference samples are accurately identified and effectively mitigated. By comparison, when the proposed approach is performed, the carrier-to-noise ratio of the software-defined receiver achieves 1.95 and 0.22 dB-Hz improvements compared with the non-mitigation and hard threshold pulse blanking cases, respectively, indicating that the proposed approach provides strong robustness for the B2a receiver in the presence of DME pulse interference. The analysis in this study benefits the development of pulse interference mitigation methods for the BDS receivers in aviation navigation.