Instantaneous Frequency Estimation of Nonstationary Jammer Based on TVAR for DSSS

Abstract

Direct-sequence spread-spectrum receivers are sensitive to nonstationary jammers, and instantaneous frequency (IF) estimation is an important component of antijamming. Time-varying autoregressive (TVAR) parametric modeling time–frequency analysis avoids the limitation of resolution by observation time and has the advantage of high time–frequency resolution. However, the performance of the TVAR model for IF estimation is affected by such factors as basis functions. To address this problem, the TVAR model of nonstationary signals was studied, and the performances of TVAR models with different basis functions for IF estimation of linear frequency modulation (LFM) and nonlinear frequency modulation (NLFM) jammers were investigated. Conclusions were drawn, and the optimal basis for the TVAR model used for IF estimation of LFM and NLFM jammers was obtained. The results provide a basis for applying of the TVAR model to nonstationary jammers.