A Few Effective Preprocessings in Synthetic Aperture Sonar System
Two effective preprocessings of the detected signals in synthetic aperture sonar system are presented.
One of them is the preprocessing to eliminate the effect of the phase turbulence of the medium. The fundamental idea is the utilization of the reference signal detected at a fixed point on the scanning plane and to take the correlation between it and the signal detected by a scanning detector to cancel the effect of the turbulence. The theoretical considerations are assured by computer simulation. Also a complete system is constructed and a typical experimental result is presented which shows the effect dramatically.
The other preprocessing is based on the utilization of superposition of complex images obtained by multiple frequencies of waves, and it is divided further into two categories; i) superposition after linear signal processing and ii) superposition after nonlinear heterodyne processing. As for the former technique, the effect of the spectral synthesis in frequency domain to increase the range resolution is discussed theoretically. As for the latter technique, discussion made is on the effect of changing the frequencies of the reference waves nonlinearly in synthetic aperture sonar systems. Basic experimental results are also shown.
Although most of the results have been or are to be submitted as papers in a few journals(Refs. 2 and 5–8),, comprehensive discussions are presented in this paper.
KeywordsSynthetic Aperture Radar Multiple Frequency Spectral Synthesis Scanning Plane Sonar System
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- 2.T. Sato and 0. Ikeda, “Sequential Synthetic Aperture Sonar System”, submitted to IEEE Trans. on Sonies and Ultrasonics.Google Scholar
- 3.L. J. Cutrona, “Synthetic Aperture Radar” in Radar Handbook, M. Skolnik, Ed. (McGraw-Hill, New York, 1970 ), Chap. 23.Google Scholar
- 5.O. Ikeda, T. Sato, and H.Ohshima, “Synthetic aperture sonar in turbulent media”, accepted for publication in J. Acoust. Soc. Am.Google Scholar
- 6.O. Ikeda, T. Sato, and H. Fujikura, “Synthetic aperture sonar in turbulent media(II)”, to be submitted to J. Acoust. Soc. Am.Google Scholar
- 7.T. Sato and O. Ikeda, “Superresolution ultrasonic imaging method by combining spectral synthesis with aperture synthesis”, submitted to J. Acoust. Soc. Am.Google Scholar
- 8.T. Sato, O. Ikeda, and H. Fujikura, “Nonlinear beating in synthetic aperture sonar”, to be submitted to J. Acoust. Soc. Am.Google Scholar
- 10.F. N. Keating, R. F. Koppelmann, and R. K. Mueller, “Maximization of Resolution in Three Dimensions” in Acoustical Holography, N. Booth, Ed. ( Plenum Press, New York, 1975 ), Vol. 6, pp. 577–595.Google Scholar