Optical Processing for Sonar Arrays
Abstract
We present an adaptation of the BEAMTAP (Broadband and Efficient Adaptive Method for True-time-delay Array Processing) algorithm, previously developed for wideband phased array radars, to lower bandwidth applications such as sonar. This system utilizes the emerging time or wavelength multiplexed optical hydrophone sensors and processes the cohered array of signals in the optical domain without conversion to the electronic domain or digitization. Modulated signals from an optical hydrophone array are pre-processed then imaged through a photorefractive crystal where they interfere with a reference signal and its delayed replicas. The diffraction of the sonar signals off these adaptive weight gratings and detection on a linear time-delay-and-integrate charge coupled device (TDI CCD) completes the true-time-delay (TTD) beamforming process. Optical signals focused on different regions of the TDI CCD accumulate the appropriate delays necessary to synchronize and coherently sum the acoustic signals arriving at various angles on the hydrophone array. In this report, we present an experimental demonstration of TTD processing of low frequency signals (in the KHz sonar regime) using a TDI CCD tapped delay line. Simulations demonstrating the performance of the overall system are also presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1999
- Accession Number
- ADA368089
Entities
People
- Dana Anderson
- Kelvin Wagner
- Lloyd Griffiths
Organizations
- University of Colorado Boulder