NTS-1 (TIMATION III) Quartz-and Rubidium-Oscillator Frequency-Stability Results,

摘要

The report describes frequency stability results obtained from the NTS-1 satellite. NTS-1 has three on-board frequency sources: one quartz oscillator and two rubidium resonators. These are used to derive the precise time and frequency signals radiated by the spacecraft. The data taken from each of three 2.5-hr daily passes are time difference (range) or frequency difference (doppler). These data are incorporated into a single value for each pass which is subsequently used in computing long-time Allan-variance results. The results presented here employ single-frequency measurements at 335 MHz. Analysis of these results indicate an effect on measured frequency stability that correlates with a resonant term in the orbit. The results further indicate the rubidium frequency depends on the spacecraft temperature, which confirms previous NRL preflight analysis.