Citation
Abstract
The spectrum of tropospheric delay fluctuations expected for a DSN antenna at time scales <100 s has been calculated. A new feature included in these calculations is the effect of aperture averaging, which causes a reduction in delay fluctuations on time scales less than the antenna wind speed crossing time, …5-10 s. On time scales less than a few seconds, the Allan deviation sigma (¢t) / (¢t)+1, rather than y sigma (¢t) / (¢t) 1=6 without aperture averaging. Due to thermal radiometer noise, y calibration of tropospheric delay fluctuations with water vapor radiometers will not be possible on time scales less than …10 s. However, the tropospheric fluctuation level will be small enough that radio science measurements with a spacecraft on time scales less than a few seconds will be limited by the stability of frequency standards and/or other nontropospheric effects.
Details
- Volume
- 42-124
- Published
- February 15, 1996
- Pages
- 1–7
- File Size
- 296.4 KB