Dissertation > Industrial Technology > Automation technology,computer technology > Automation technology and equipment > Automation systems > Data processing, data processing system

Research on the Multibeam Detecting Technology of Shallow Subbottom Profile

Author ZhuJianJun
Tutor LiHaiSen
School Harbin Engineering University
Course Communication and Information System
Keywords Multibeam FRFT The source signal encoding AR prediction filtering Weighted least squares fit
Type Master's thesis
Year 2008
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Today, shallow stratigraphic section instrument is widely used in water seabed sediment acoustic detection equipment . With shallow stratigraphic detection system performance continues to improve , and new fields of application, multi-beam probing shallow strata , especially multi-beam parameter probe will become shallow stratigraphic Seabed detection technology trends. But the receiving array aperture is too large development of this technology is a major obstacle . This article will FRFT parameter multibeam technology into shallow strata probe, the lower the receiving array aperture required to eliminate aliasing between the echo signal , while the shallow layer detection technology for a preliminary study . Chirp signals in different fractional Fourier domain show different aggregation . As FRFT technique for multi- component Chirp signal processing performance with superior for anti- echo signal aliasing technical requirements , this paper studied the principles and application of FRFT technology , and multi-beam light source stratigraphic signal encoding detection systems have been studied . Clarifies response signal preenvelope for FRFT, and launched Chirp signal distribution in the fractional Fourier domain location theoretical formula . According to this study theoretical formula derived source signal encoded in accordance with , and ultimately FRFT used source signal coding and anti- aliasing purposes echo signals given computer simulation of the process . Application of matched filtering combined treatment with AR prediction filtering method to calculate a smaller spacing impulse response of sedimentary layers to improve the signal limited by the bandwidth limitations of the detection resolution . Using the weighted least squares fitting method further deposited layer at overlapping echo location and magnitude of the impulse response is estimated to further improve the resolution of the simultaneous estimation of sedimentary layers to get higher resolution acoustic impedance profile . As a serious impact on high-frequency sound attenuation impulse response of the inversion layer is deposited , the estimation process takes into account the impact sound attenuation , resulting in a more reasonable estimate acoustic impedance . Detailed simulation of the prediction filter and weighted least squares fitting procedure , and gives the estimation error .

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