Citation
Abstract
NASA is interested in using the technique of arraying smaller-diameter antennas to increase effective aperture to replace the aging 70-m-diameter antennas of the Deep Space Network (DSN). Downlink arraying using the 34-m-diameter and 70-m-diameter antennas is routinely performed. Future scenarios include extending the technique to uplink arraying where a downlink signal may not be available. Atmospheric turbulence causes decorrelation of the arrayed signal, and becomes more severe at higher frequencies such as at the uplink allocations near 34 GHz and 40 GHz. This article expands the study initiated in a previous article that focused on average array loss statistics extracted from Site Test Interferometer (STI) data. In that study, cumulative distributions of the annual and monthly expected phasing loss were derived from STI data collected at the Goldstone and Canberra DSN complexes. For a two-element array, the average array loss cannot exceed 3 dB. This article considers the instantaneous (short time scale) array loss that sometimes exceeds 3 dB for a two-element array. We also consider cases of three-element arrays, which behave somewhat differently. The short time scale statistics of array loss at 7.15 GHz and 34.5 GHz are compared against the average array loss statistics for the best-case and worst-case weather months for the Goldstone and Canberra DSN sites.
Details
- Volume
- 42-198
- Published
- August 15, 2014
- Pages
- 1–20
- File Size
- 1.7 MB