As the key process to ensure the test accuracy and quality, the dynamic calibration of the GNSS attitude measuring instrument is often embarrassed by the lack of the rigid enough test platform and an accurate enough calibration reference. To solve the problems, a novel dynamic calibration method for GNSS attitude measurement based on altazimuth mount is put forward in this paper. The principle and implementation of this method are presented, and then the feasibility and usability of the method are analyzed in detail involving the applicability of the mount, calibrating precision, calibrating range, base line rigidity and the satellite signal involved factors. Furthermore, to verify and test the method, a confirmatory experiment is carried out with the survey ship GPS attitude measuring instrument, and the experimental results prove that it is a feasible way to the dynamic calibration for GNSS attitude measurement.
Time and Frequency Remote Calibration System (TFRCS) based on GPS common-view has been designed by National Time Service Center (NTSC), which is used to realize time and frequency calibration for remote users as well as the precise time traceable to UTC (NTSC) for the local reference time. The high precision PCI plug-in time interval counter is the critical measuring instrument of TFRCS, which is self developed to measure the time interval between two 1 PPS signals from GPS timing receiver and local reference time. The basic principle of time interval counter and the realization method of bottom driver based on PCI are reviewed. On this basis, the method and the measuring results of time interval data based on the driver program are then presented. An experiment has been designed to test the performance of the self developed time interval counter. Research on the technology of time-interval measurement has a very important significance for TFRCS. Furthermore, it also can be used in the field of high precision time-interval measurement.