Chapter 33 Progress on Sapphire Hydrogen Maser for Beidou Navigation System

摘要

Active hydrogen maser is one of the most important equipments for the Beidou Navigation system. The stability of active hydrogen maser does influence the synchronize accuracy of time and frequency between the satellites and the ground devices. In order to improve the stability of Sapphire Hydrogen Maser, we had done several improvements on the physical package and electrical package, which include magnetic shield improvements, developing a method to probe the hydrogen atom beam, getter pump improvement and cavity auto-turning system researching. The factor of magnetic shield has been improved to above 10~5. We had researched several kinds of getter materials which can improve the lifetime of physical package. We had designed a new form of getter pump, which make the volume of physical package smaller than ever. The stability of the maser after improvement can get 3.1 × 10~(-13) @ 1 s, 2.9 × 10~(-15) @ 1 day.