Underwater single beam circumferentially scanning detection system using range-gated receiver and adaptive filter. Issue 16 (8th September 2017)

• Record Type: Journal Article
• Authors: Tan, Yayun; Zhang, He; Zha, Bingting
• Is Part Of: Journal of modern optics. Volume 64:Issue 16(2017)
• Page Start: 1648
• Page End: 1656
• Publication Date: 2017-09-08
• Subjects: Underwater laser -- backscattering suppression -- range-gated -- adaptive filter -- ranging accuracy; Optics -- Periodicals; 535
• DOI: 10.1080/09500340.2017.1310315
• Languages: English
• ISSNs: 0950-0340

Abstract

Abstract: Underwater target detection and ranging in seawater are of interest in unmanned underwater vehicles. This study presents an underwater detection system that synchronously scans a collimated laser beam and a narrow field of view to circumferentially detect an underwater target. Hybrid methods of range-gated and variable step-size least mean squares (VSS-LMS) adaptive filter are proposed to suppress water backscattering. The range-gated receiver eliminates the backscattering of near-field water. The VSS-LMS filter extracts the target echo in the remaining backscattering and the constant fraction discriminator timing method is used to improve ranging accuracy. The optimal constant fraction is selected by analysing the jitter noise and slope of the target echo. The prototype of the underwater detection system is constructed and tested in coastal seawater, then the effectiveness of backscattering suppression and high-ranging accuracy is verified through experimental results and analysis discussed in this paper.