Citation
Abstract
Site test interferometers (STIs) have been deployed at Goldstone, California, in order to (1) assess the suitability of Goldstone as an uplink array site, and (2) statistically characterize atmospheric-induced phase fluctuations over a ~250-m baseline for the Goldstone climate for use in future array link scenarios. Beginning in August 2008, dual water vapor radiometers (DWVRs) were deployed next to each antenna element of the STI residing at the Venus site at Goldstone forming a baseline of similar length. The differenced path delay between the two WVR units forms an additional data type that can be used to validate the STI phase fluctuations and confirm the atmospheric nature of these fluctuations. This study was motivated by several considerations. First, the use of a single WVR provides single-point path delay fluctuation measurements that could be used as an ancillary data type, to compare against the magnitude of STI path delay fluctuations. Second, the use of two WVRs allows estimation of their differenced path delay, which produces a data type that could be correlated directly against the STI phase difference fluctuations (filtered to remove long-period nontroposphere variations). This can allow one to assess whether STI fluctuations are due to troposphere or can be used to identify suspicious signatures to verify whether equipment problems or other anomalies exist. Such an experiment could also be used to explore the feasibility and limitations of using a DWVR in place of an STI to characterize atmospheric phase fluctuations for a generally “dry” climate when liquid content in the atmosphere is minimal (up to a certain limit occurring less than 1 percent of the time). This article reports on initial study results of a comparison of differenced path delay statistics derived from both the DWVR and the STI, as well as including discussion of prospects for future DWVR experiments using WVRs of improved design and optimal experimental procedures.
Details
- Volume
- 42-188
- Published
- February 15, 2012
- Pages
- 1–21
- File Size
- 2.5 MB