Name DCQGMP-SD S-MPDR / ST-MPDR / DCQGMP-SD & MPDR O([N.sub.J][N.sub.G][N.sub.Q][N.sup.2.sub.S]) Proposed / Name Periodic estimation S-MPDR / ST-MPDR / DCQGMP-SD & MPDR / Proposed O([N.sub.s][log.sub.2]([N.sub.s])) Name STFT and ISTFT
S-MPDR / ST-MPDR / DCQGMP-SD & MPDR / Proposed O([N.sub.[omega]][M.sub.2][log.sub.2]([M.sub.2])) Name Interference suppression S-MPDR O([N.sup.3]) ST-MPDR O([N.sup.3.sub.[tau]][N.sup.3]) DCQGMP-SD & MPDR O([N.sup.3]) Proposed O([M.sub.2][M.sub.2][N.sup.3])
When p = 2, the FLOSTFT method degenerates into the STFT method, and the corresponding IFLOSTFT evolves into the ISTFT
method,;hence, the improved FLOSTFT is a generalized algorithm.
Through the RFI identification and suppression towards all the instantaneous frequency spectrums, the signal RFI suppressed can be obtained by ISTFT.
Processing the instantaneous frequency spectrum at every certain time, the SAR echo after RFI suppression will be reconstructed by ISTFT.
Accordingly, the computation loads of STFT and ISTFT are similar, and [M.sub.ST FT] is