Abstract

Allan et al claimed in 1985 to have demonstrated a terrestrial rotational Sagnac effect (amounting to a [] of about 240-350 nonoseconds) by means of an around-the-world system of GPS satellite signals. This effect was previously demonstrated by Michelson and Gale in 1925. The much longer distances available with the satellites, however, generate bigger time differences (in the order of thousands of nanoseconds) in addition to the rotational Sagnac effects. The authors attribute these large deviations to inherent differences in the clocks, uncertainty of satellite ephemeris, etc. It is contended here, however, that these large differences represent solar (i.e. orbital) and even galactic Sagnac effects. An inductive analysis of the data and a subsequent deduction from first principles leads to the latter conclusion. A discussion of the results follows.