MMA Memo #136

Correcting for Decorrelation Due to Atmospheric Phase Errors

M.A. Holdaway [1], F.N. Owen [1]

September 20, 1995

Keywords: phase errors, imaging, deconvolution

We explore how image reconstruction degrades with uncorrected phase errors and how corrections can be made for the mean decorrelation even when we cannot correct for the actual phase errors. Correcting the visibility amplitude for the mean decorrelation as a function of baseline length improves the reconstructed image. Deconvolving the dirty image by a point spread function which includes the statistical effects of the phase errors as well as the effects of the incomplete Fourier plane sampling results in superior images. The latter technique permits very good image reconstruction even in the presence of phase errors as high as 70 degrees, and permits some sort of reconstruction in the presence of 105 degree rms phase errors. The MMA's phase error specifications need to be reevaluated in light of these new imaging techniques.

[1] NRAO/NM

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Last modified: 09 December, 1999