DME Impulse interference Mitigation Method Based on Subspace Projection and CLEAN Algorithm

To mitigate the deleterious influence of distance measure equipment (DME) interference on Orthogonal Frequency Division Multiplexing (OFDM) receiver of L-band Digital Aeronautical Communications System 1(L-DACS1) operating as an inlay system, a new interference suppression receiver for L-DACS1 system is proposed based on joint subspace projection and CLEAN algorithm. Firstly, subspace projection algorithm is used to suppress the strong DME interference by projecting the array received signals on the orthogonal complement space of interferences. Then, CLEAN algorithm is proposed to estimate direction of arrivals of OFDM signals based on the repetition property of the cyclic prefix of an OFDM symbol .Finally, conventional beam forming algorithm is used for extracting the OFDM direct path signals. Computer simulation results show that the proposed OFDM receiver can effectively suppress the strong DME impulse interference and OFDM scattering signal to improve the reliability of the L-DACS1 system.