Variable Projection Order Adaptive Filtering Algorithm for Self⁃interference Cancellation in Airborne Radars

The adaptive filtering algorithm with a fixed projection order is unable to adjust its performance in response to changes in the external environment of airborne radars. To overcome this limitation， a new approach is introduced， which is the variable projection order Ekblom norm-promoted adaptive algorithm （VPO-EPAA）. The method begins by examining the mean squared deviation （MSD） of the EPAA， deriving a formula for its MSD. Next， it compares the MSD of EPAA at two different projection orders and selects the one that minimizes the MSD as the parameter for the current iteration. Furthermore， the algorithm’s computational complexity is analyzed theoretically. Simulation results from system identification and self-interference cancellation show that the proposed algorithm performs exceptionally well in airborne radar signal self-interference cancellation， even under various noise intensities and types of interference.