- Gridless Narrow-Angle Astrometry
Gridless Narrow-Angle Astrometry (GNAA) is an
astrometry technique developed at theCalifornia Institute of Technology Jet Propulsion Laboratory under contract toNASA . GNAA allowsstar positions to be measured without first setting up a grid of reference stars; instead, it sets up a reference frame using several reference stars and a target star observed from different locations, and star positions are calculated using delay measurements from the separate observations.GNAA was developed to give an accuracy of 1 micro-
arcsecond to the early stages of theSpace Interferometry Mission .References
* [http://planetquest.jpl.nasa.gov/SIM/science_shaklan.pdf A New Approach to Micro-arcsecond Astrometry with SIM Allowing Early Mission Narrow Angle Measurements of Compelling Astronomical Targets]
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