GPS week roll-voer and Y2K compliance for NBS-type receivers, and absolute calibration of the nist primary receiver

摘要

The NBS-type receiver software was modified to account for both the GPS end-of-week crossover and for the Y2K event. Receivers using this software were tested by personnel from the National Institute of Standards and Technology and the U.S. Naval Observatory using a simulator at the Naval Research Laboratory. An independent tst was performed by a private company. The software now appears to be fully compliant with requirementes for both the GPS week roll-over and the Y2K events. Since the NBS-type receivers are still the predominant receiver for time transfer among laboratories which generate International Atomic Time, this receiver was given significant attention. In the process, an absolute calibration of the delay through the primary NIST GPS common-view receiver was completed. This calibration agrees within its 2.8 ns uncertainty both with the value from an estimate in June 1986, which has been used continuously since then, and with an absolute calibration in April of 1987.