CRITICAL EVALUATION OF THE MOTOROLA M12+ GPS TIMING RECEIVER VS. THE MASTER CLOCK AT THE UNITED STATES NAVAL OBSERVATORY, WASHINGTON, DC

Abstract : The paper describes the challenge of calibrating a new GPS Timing receiver so that its timing performance can be characterized with traceability to true UTC. This effort involved development of a custom test bed with improved software, installing the test bed at USNO, calibrating all the elements if the USNO and test bed equipment, collecting the data, and data analysis. This test bed allows testing of four GPS Timing receivers simultaneously so that variations in the manufacturing process and "zero baseline" comparisons can be evaluated. The work was extended to include a test of the level of synchronicity obtained between receivers separated by a 21.5 km baseline.