Oscillator Sources for a DORIS Satellite SDR Receiver System

Benjamin H. Barnum, Chris Haskins, Wesley Millard, David Rainwater, and Michael Kelly

Abstract:	The global Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) beacon system is currently used to make measurements of the Total Electron Content (TEC) of the ionosphere, satellite position and orbit determination, and measurement of the Total Water Vapor Content (TWVC) of the lower atmosphere. The DORIS network is comprised of a system of over 50 ground beacon stations transmitting a precisely controlled phase-locked, dual frequency (2.036 GHz and 401.25 MHz) signals. The radio signals are delayed by the electron content, and to a lesser extent the water vapor, along the path from the transmitting station to the satellite receiver. This delay is frequency dependent, thereby enabling measurements of the path integrated TEC and TWVC. The Johns Hopkins University Applied Physics Laboratory and the University of Texas at Austin, Applied Research Lab are working on adapting the space qualified Frontier Software Defined Radio (SDR) for use as a dual band DORIS receiver on a small satellite or cubesat. The reference oscillator used for this system is a critical part of enabling the measurements, and must maintain a minimum Allan deviation of 10-11 or better. Higher precision sources enable more precise slant path measurements of the DORIS signals, and some of the smaller scale variations of the ionosphere. We review the oscillator system requirements for the Frontier SDR and relate these to the science goals of the low earth orbit satellite mission to measure TEC, TWVC, orbit position, and smaller scale ionosphere irregularities.
Published in:	Proceedings of the 44th Annual Precise Time and Time Interval Systems and Applications Meeting November 26 - 29, 2012 Hyatt Regency Reston Town Center Reston, Virginia
Pages:	351 - 360
Cite this article:	Barnum, Benjamin H., Haskins, Chris, Millard, Wesley, Rainwater, David, Kelly, Michael, "Oscillator Sources for a DORIS Satellite SDR Receiver System," Proceedings of the 44th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, November 2012, pp. 351-360.
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