Coherent Integration in Optical Interferometry

Abstract

Optical Interferometry has long been limited by low SNR making it nearly impossible to measure the small visibilities required to make resolved images. Although the SNR exists in the raw data, much SNR is lost in the conventional squared-visibility processing. In modern interferometers fringes are recorded simultaneously at many wavelengths and baselines. This makes phase-referencing possible, which is the key to coherent integration, which in turns can greatly improve the SNR of measurements, making small-amplitude resolving measurements possible. In this paper we will detail the theory of coherent integration. We will also explain why coherent integration should, in most cases, be carried out during post-processing in software rather than in real-time in hardware. We will then compare it to conventional processing approaches for some data from the Navy Optical Interferometer. We will demonstrate how coherent integration can improve the accuracy of observations.

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Document Details

Document Type
Technical Report
Publication Date
Jul 01, 2012
Accession Number
ADA573780

Entities

People

  • A. M. Jorgensen
  • D. Hutter
  • D. Mozurkewich
  • E. K. Baines
  • G. T. Van Belle
  • H. R. Schmitt
  • John Thomas Armstrong
  • S. Restaino
  • Tessa Hall

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Abstracts
  • Air Pressure
  • Amplitude
  • Base Lines
  • Calibration
  • Computations
  • Delay Lines
  • Diameters
  • High Resolution
  • Interferometry
  • Kalman Filters
  • Measurement
  • Measuring Instruments
  • Observation
  • Observatories
  • Power Spectra
  • Visibility

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Optical Physics and Photonics.
  • Radar Systems Engineering.