A GPS Time-pulse Radiator for Measuring Time-stamp Accuracy of a Radio Telescope Array

摘要

A portable GNSS time-pulse radiator (GTR) device for testing the time-stamp accuracy was developed to independently verify how well each MeerKAT radio telescope antenna and its associated processing stages are aligned to UTC. The telescope's time and frequency reference clock ensemble consists of two hydrogen masers, an ultrastable crystal and GPS disciplined Rubidium clocks. During operation, the GTR radiates a broadband GPS time synchronised RF timing signal at a known distance from the telescope antenna and the corresponding timestamps are compared to the expected value. Recent GTR timing test results from one of MeerKAT's antennas showed that the telescope time and UTC were aligned within the instrument's 100 ns uncertainty.