NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Improved mapping of radio sources from VLBI data by least-square fitA method is described for producing improved mapping of radio sources from Very Long Base Interferometry (VLBI) data. The method described is more direct than existing Fourier methods, is often more accurate, and runs at least as fast. The visibility data is modeled here, as in existing methods, as a function of the unknown brightness distribution and the unknown antenna gains and phases. These unknowns are chosen so that the resulting function values are as near as possible to the observed values. If researchers use the radio mapping source deviation to measure the closeness of this fit to the observed values, they are led to the problem of minimizing a certain function of all the unknown parameters. This minimization problem cannot be solved directly, but it can be attacked by iterative methods which we show converge automatically to the minimum with no user intervention. The resulting brightness distribution will furnish the best fit to the data among all brightness distributions of given resolution.
Document ID
19860000935
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Rodemich, E. R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 12, 2013
Publication Date
August 15, 1985
Publication Information
Publication: The Telecommun. and Data Acquisition Progr. Rept.
Subject Category
Communications And Radar
Accession Number
86N10402
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available