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Objectives：Traditional echo simulator of synthetic aperture sonar (SAS) is based on the assumption that transmitter and receiver beam patterns are rectangle within mainlobe, which is determined by 3 dB beamwidth of beam pattern. This neglects the echo signal outside the mainlobe. Besides, the modulation of transmitter and receiver beam patterns is not considered. Methods：Depending on the instantaneous geometry relationship among transmitter, receiver and target, the echo simulation of SAS considering the modulation of transmitter and receiver beam patterns is carried out. Then, the influence of transmitter and receiver beam patterns on SAS imaging is discussed by the back projection algorithm. Results and Conslusions: Traditional array signal processing based on weighting is further conducted to show the influence of transmitter and receiver beam patterns on imaging results. The results are useful for the suppression of spectrum alias in the azimuth direction. Moreover, they are also helpful for the simulation verification and analysis of performance parameters of designed SAS systems. [ABSTRACT FROM AUTHOR]

With Loffeld’s bistatic formula (LBF), the transfer function of the multireceiver synthetic aperture sonar (SAS) can be decomposed into the quasi-monostatic term and bistatic deformation term. For this model, the phase error in the 2D frequency domain is quantitatively analyzed. The results indicate that this model can fully satisfy the imaging need with high performance. Based on that, a new imaging method is proposed. Firstly,the range variant term of bistatic deformation phase should be first compensated in the 2D frequency domain via the range-dependent sub-block processing. Subsequently, the monostatic SAS equivalent data can be obtained by rearranging the multireceiver data in order in the 2D time domain. Then, a range-Doppler (R-D) algorithm is exploited to process the monostatic SAS equivalent data. Finally, the processing results of simulated and real data validate the proposed method. [ABSTRACT FROM AUTHOR]