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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

In-Flight Auto-Tune of an Airborne Synthetic Beamforming Antenna

Lamarra, Norm, Kelkar, Anand, Vaughan, Thomas 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / At ITC 2009, we described the real-world complications of fielding an airborne Synthetic beamforming Telemetry System, which simultaneously supports 20 individual beams (10 at each of 2 polarizations). We described how our layered Open-Source software approach helped us to modify the system rapidly after delivery without disrupting mission operations. Since then, we have further extended the software toolset that we developed to dissect the System behavior via post-mission replay and analysis, and to compare high-resolution in-flight measurements with our detailed physics simulations. This analysis has shown that the most significant factor affecting operational performance of the System was variation in the relative phase of the elements from day to day. These variations were traced to a variety of hardware issues, none of which could be resolved without major cost and effort. As an alternative approach, we developed a dynamic auto-tuning capability that optimizes the phase calibration of the System using each actual signal source as it is being tracked. This results in improved signal-to-noise performance while reducing the need for dedicated in-air calibration flights that we had previously created. We believe that the flexibility of digital beamforming, allied with a modular and easily-extensible software architecture, have again proven capable of quickly and cheaply mitigating real-world operational issues, without (so far) requiring any hardware modification of the delivered System.

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