Linear Frequency Modulation Interference Suppression Based on Subspace Error Correction

Subspace projections can be used to suppress nonstationary interference, typically linear frequency modulation (LFM) interference, when the interference subspace is constructed correctly. When errors exist in the parameters used to construct the subspace, the interference suppression effect drops dramatically. To address this problem, the effect induced by the parameter estimation error is analyzed. On the basis of subspace error analysis, a method is proposed to remand the estimation error; the method finds the most accurate pair of parameters by comparing the inner products of the received signal and all the constructed interferences. When the frequency parameters are remanded, they can be used to construct the interference subspace; thus, through subspace projection, the interference in the received signal can be suppressed. In this study, this method was verified via simulation to be effective. By applying this method, the effect of subspace projection is promoted to a prominent degree, which makes it useful for LFM interference suppression.