Objectives:
Determine the extent to which a particular site (e.g., White
Sands, Goldstone, Madrid, etc.) is capable of supporting widely
distributed antenna systems for NASA’s future Ka-Band communication
links. Statistical characterization of the diurnal, annual and secular path length fluctuations at candidate sites for future distributed ground based antenna systems operating at Ka-Band applicable to all three of NASA’s current space communication ground systems and set the stage for an integrated NASA space communication network Path Length Fluctuations Statistics (rms) |
To improve the understanding of atmospheric phase stability
at Ka-band at current and future NASA potential operational
sites.Calibration Task Objective: To improve the understanding of atmospheric phase stability at Ka-band at current and future NASA potential operational sites. This research task will determine the extent to which a particular site (e.g., White Sands, Goldstone, Madrid, Canberra, Guam, etc.) is capable of supporting large aperture and widely distributed antenna systems for future NASA’s Ka-Band communication links. Benefits and Relevance:
Current status – Measured statistical amplitude and phase
cumulative distribution functions (CDF) do not exist or are
estimated with limited data at NASA current operational sites.
System planning and design for Ka-band links at these operational
sites cannot be optimally achieved unless measured amplitude
and phase statistics (CDF) at each site are obtained. In general,
the CDF will determine the system margin and system availability
due to atmospheric effects (e.g. rain, water vapor, etc). In-house (GRC) development of low cost - second generation atmospheric phase monitor (APM). The APM consist of two identical receivers observing a geosynchronous satellite signal at a wavelength of 1.5 cm and at a baseline of 256 m. Parallel Site Testing using the same APM instrument design (e.g., same electronics) at Goldstone and White Sands starting FY09 Q2. Data Analysis using the same data calibration protocols and
statistical analysis tools. The data analysis characterization
directly measures the diurnal, annual and secular root-means-square
(rms) path length fluctuations at candidate sites. |
As SCaN migrates towards the use of high frequency RF links
(e.g., Ka-Band) with the possibility of utilizing large apertures
(e.g. 34 m) and antenna arraying techniques, a site characterization
study was initiated to determine the atmospheric effects on
future Ka-Band communication links at Goldstone, White Sands,
Guam, Canberra, and Madrid.
|
|
