Precise T & F Intercomparison Between NPL, India and PTB, Federal Republic of Germany via Satellite Symphonie-1

Abstract

In this paper, we report a T and F intercomparison experiment between the National Physical Laboratory (NPL), New Delhi, India and Physikalisch-Technische Bundesanstalt (PTB), Federal Republic of Germany, carried out from May 16 to June 29, 1979. The participating earth stations were New Delhi, India and Raisting, FRG. The NPL clock was placed at New Delhi Earth Station and the Raisting Clock was calibrated with PTB/Primary standard via LORAN-C and travelling clocks. The random uncertainty of time comparisons, represented by two sample Allan Variance σ(30 seconds), was less than 10 nanoseconds. The relative frequency difference between the NPL and Raisting Clocks, SNPL, RAIS, as measured over the 44 days period was found to be-15.7 × 10^-13. The relative frequency difference between PTB Primary Standard and Raisting Clock, SPTB, RAIS during this period, was measured to be–22.8 × 10^-13. The relative frequency difference between NPL clock and PTB Primary Standard, SNPL, PTB, thus, is—7.1 × 10^-13.

The clock rate (UTC, India) evaluated in the present work as +7.1 ± 0.5 × 10^-13, agrees very well with that obtained via VLF phase measurements over one year period described in a companion paper and with USNO travelling clock time comparisons made in September, 1980.