Accurate Millisecond Level Oscillator Phase Noise Estimation for Standalone GNSS

A. Morrison

Abstract:	In this paper it will be shown that if the channel data within a GNSS receiver is handled in an effective manner, it is possible to form meaningful estimates of the local oscillator phase deviations, on time scales of 10 ms or less. Moreover, it will be shown that if certain criteria are met, these estimates will be available with related uncertainties similar to the deviations produced by a ‘typical’ OCXO. The processing delay required to form this estimate is limited to between 10 and 20 ms. In short, using the methods presented it becomes possible in nearreal- time to remove the majority of the phase noise of a local oscillator that possesses short term instability worse than an OCXO, using standalone GNSS. The implication is that this represents both a new method to accurately determine the Allan deviation of a local oscillator at time scales previously impractical to assess using a conventional GNSS receiver (Petovello & Lachapelle 1999), as well as the potential for the reduction in observable Doppler uncertainty at the output of the receiver, and ionospheric scintillation detection not reliant on an expensive local OCXO.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	3309 - 3316
Cite this article:	Morrison, A., "Accurate Millisecond Level Oscillator Phase Noise Estimation for Standalone GNSS," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 3309-3316.
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