Interlaboratory comparison of Josephson voltage standards between NIST andLockheed Martin Astronautics

Two Josephson voltage standard (JVS) systems operated at the National insti tute of Standards and Technology (NIST) and Lockheed Martin Astronautics (L MA) were compared by using four traveling Zener standards. A Measurement As surance Program MAP) protocol was adopted for the comparison, The Zener dat a were first corrected based on their pressure coefficients to compensate f or the pressure difference due to the lab elevations and local meteorologic al conditions. The Welch-Satterthwaite formula and effective degrees of fre edom DOF) were then used to calculate the expanded uncertainty. The mean di fference between the measurements of the two laboratories was found to be 0 .059 muV with an expanded uncertainty of +/- 0.189 muV at the 95% confidenc e level.