Suppression of grating lobes in stepped-frequency train

Abstract

For uniform frequency stepped pulse trains, there can be undesirable peaks of the autocorrelation function, known as "grating lobes". In this paper we address this issue, using an approach which allows us to suppress grating lobes below a desired threshold level in the case of appropriately chosen stepped frequency waveforms, i.e., sequences of narrowband pulses that span the desired bandwidth. We discuss in detail how to choose relevant parameters in order to produce such waveforms with small grating lobes, and give examples of waveforms with small overlap ratio. We also discuss the issue of high sidelobes in the vicinity of the main lobe, which are inevitable in a train of LFM waveforms, and show that it is possible to suppress these, as well as the grating lobes, by means of phase modulation.

Motion Target Imaging by Non-Linear Stepped-Frequency Chirp Pulse Train

“…In addition, the grating lobes are partially suppressed by about 32 dB. For further suppression of the grating lobes when using a stepped-frequency chirp pulse train, several methods and some specific relationships on the pulse train parameters have been presented in [10][11][12].…”

Suppression of grating lobes in stepped frequency LFM pulse train using PSO

“…These grating lobes appear in the form of high spikes and hence reduce the range resolution capability of LFM pulse train. Different techniques for acceptable suppression or complete rejection of grating lobes are dealt in [1][2][3][5][6][7][8]. Maron [6,7] has proposed to use variable pulse widths to suppress the grating lobes but it leads to loss of periodicity of pulse train.…”

Application of Super-Sva to Stepped-Chirp Radar Imaging With Frequency Band Gaps Between Subchirps

“…To meet the requirements of higher resolution, stepped frequency technique has become an alternative method for radar systems. Stepped frequency chirp signal (SFCS), as an important signal form of SAR imaging, has been used to achieve high resolution with low instantaneous bandwidth and low sampling rate, and has been paid more and more attention [1][2][3][4][5][6]. By transmitting a train of narrow-bandwidth chirp pulses carried on stepped frequencies, the corresponding echoes are then received and synthesized into a much wider band signal so as to achieve high range resolution.…”

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Abstract-It is well-known that the stepped-frequency chirp signal (SFCS) technique is one of the very effective approaches for achieving high range resolution in radar [1][2][3][4][5]. The SFCS is a train of subchirp pulses with up-stepped or down-stepped carrier frequencies.

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