Low Sidelobe Range Profile Synthesis for Sonar Imaging Using Stepped-Frequency Pulses

A stepped-frequency sonar imaging method with low range sidelobe peak (SLP) is proposed. Two linear frequency modulation (LFM) pulses with partly overlapped bands and opposite modulation directions are used; and both auto-and cross-correlation functions are taken to synthesize the low SLP range profile. With the presence of echo misalignment, a 2-D searching method is given to find the optimal signal parameters at the lowest SLP. Numerical simulations show that the proposed method can suppress the range SLP effectively and requires only a half instantaneous system bandwidth, when compared with the traditional method using a single LFM pulse.