Co-frequency interference suppression of airborne VDB  receiver based on blind signal separation

Aiming at the problem of co-frequency interference of ground-based augmentation systems (GBAS) airborne VHF Data Broadcasting (VDB) receiver in the process of precise approach and landing for civil aviation aircraft using GBAS, a blind signal separation algorithm is proposed to separate the desired signal from the same frequency interference signal received by VDB receiver. The desired signal is obtained by identifying the airport ID in the decoded data, so as to suppress the same frequency interference signal. Based on fast independent component analysis (Fast ICA) algorithm, natural gradient algorithm and equivariant adaptive separation via independence (EASI) algorithm, the mechanism of separating mixed signals received by VDB receivers and the realization of co-channel interference suppression are analyzed and simulated. The simulation results show that the three algorithms can effectively separate the desired signal from the same frequency interference signal, and then suppress the same frequency interference. It is concluded that fast ICA algorithm is more suitable for the same-frequency interference suppression of VDB signals by comparing the convergence speed, crosstalk error and bit error rate of the three algorithms.