Geodesy and astrometry by transatlantic long base line interferometry

Abstract

We report geodetic and astrometric results from the analysis of fringe frequency observations from a series of three long base line interferometry (LBI) experiments carried out in 1973 between the 46‐m antenna of the Algonquin Radio Observatory, Lake Traverse, Canada, and the 2‐m antenna at Chilbolton Field Station, Chilbolton, England. The rms deviation from the mean of the estimates of the length and orientation of the 5251‐km equatorial component of the base line from all three experiments is 1.05‐m and 0.015″, respectively. The experiments also yielded positions of five extragalactic radio sources. The reported positions, each of which is from only a single experiment, have uncertainties of about 0.2″ in declination (except for low declination sources) and about 0.01 s in right ascension. The LBI determination of the length and orientation of the equatorial component of the base line is compared to the corresponding values derived from Naval Weapons Laboratory 9D (NWL‐9D) coordinates for the antennae. The two length measurements agree in scale within quoted experimental errors, however, the NWL‐9D coordinate frame is found to be rotated 0.867″±0.1″ to the east relative to the average terrestrial frame of the Bureau International de l'Heure (BIH), (LBI coordinate frame). This is in good agreement with the expected misalignment of 0.65″±0.2″. The differences in the rates of the clocks used at each end of the base line were also determined and compared to Loran‐C observations.