Broadband Beamforming Algorithm Based On VFD And Its Implementation On C6748

Compared to narrowband signal, broadband signal has numerous advantages, forinstance, taking more target information, weaker reverberation background correlation, whichare very conducive for detecting and featuring extraction of a target. In order to furtherameliorate the resolution and the detection accuracy of the sonar system, especially toimprove the detection capabilities of the small-scale targets.It has important theoreticalsignificance and practical value to increase research in the system of sonar with broadbandsignal processing，especially the technology of broadband beamforming.In this paper, the main research lines are the following several points:I. Studied the theory and structure of broadband beamforming technology in the timedomain based on fractional delay. Described three designs of fractional delay filter andsimulated them.Then analyzed the Performance, complexity, stability and flatness of eachdesign.II. Discussed the principles and methods of constant beamwidth beamforming infrequency domain. Studied in detail several calculation method of weighting coefficients forconstant beamwidth beamforming of linear or any arrangement structure array in frequencydomain, simulated the algorithms, verified their correctness, and then analyzed theirperformance. Studied and analyzed the theory to achieve constant beamwidth beamformingin time domain by designing FIR filters, and gave the optimization criterion of filterdesigning.III. Described a VFD FIR filter design based on the Farrow structure, and proposed anew time domain constant beamwidth beamforming method combined VFD FIR filters.VFD FIR filter based on Farrow structure can be adaptively depending on the delayconditions quickly adjust the filter coefficients. The design of combining VFD FIR filter andamplitude compensation filter together simplifies the computational complexity, savesstorage space and improves the real-time nature and convenience of the equipment when itwas used for beamforming.IV. Based on the existing trawl sonar system, use TI’s TMS320C6748DSP for algorithmsimulation as signal processing platform. Use the C++programming language to writeC6748-based broadband beamforming algorithm code and apply on DSP. Analysis to achieve the goal of real-time signal processing hardware and software implementations.