Constrained Minimum Square Error Frequency Step in Stepped Multiple Frequency LFM Radar

Abstract

In this paper, unequal interval stepped multiple frequency Linear Frequency Modulation (LFM) pulse radar is modified to improve the side-lobe characteristics of Synthetic Wideband Waveform Processing (SWW). The proposed Constrained Minimum Square Error (CMSE) method, which employs some constraints on the output level of SWW, provides the parameters associated with the intervals of frequencies to mitigate problems associated with the side-lobe level in the vicinity of main-lobe. The parameters of the unequal interval frequency step are obtained by solving the optimization problem with the constraint condition that the side-lobe level of SWW is lowered in the vicinity of the main-lobe while it is increased at the null of LFM pulse compression. The simulation results are shown that unequal interval stepped multiple frequency LFM using CMSE method with only 8 frequencies, Discrete Fourier Transformation without weighting, suppressed the side-lobe level below -20dB.