title: Precision Geodesy via Radio Interferometry.
abstract: Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds.
authors.forename: H F
authors.initials: HF
authors.lastname: Hinteregger
authors.forename: I I
authors.initials: II
authors.lastname: Shapiro
authors.forename: D S
authors.initials: DS
authors.lastname: Robertson
authors.forename: C A
authors.initials: CA
authors.lastname: Knight
authors.forename: R A
authors.initials: RA
authors.lastname: Ergas
authors.forename: A R
authors.initials: AR
authors.lastname: Whitney
authors.forename: A E
authors.initials: AE
authors.lastname: Rogers
authors.forename: J M
authors.initials: JM
authors.lastname: Moran
authors.forename: T A
authors.initials: TA
authors.lastname: Clark
authors.forename: B F
authors.initials: BF
authors.lastname: Burke