July/August 2009

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The approaching solar maximum will produce magnetic storms, ionospheric storms, and disruptions to radio signals that directly affect the world’s technical infrastructure, including GNSS.  Using a model developed at Cornell University, the authors describe the behavior of the Earth’s atmosphere during solar storms and the resulting phenomenon of ionospheric scintillation. They propose a method for evaluating the ability of GPS receivers to operate through scintillation before the next solar maximum arrives in 2013.

This is an updated version of the web article,  Saving SVN49, that includes discussion of the elevation-dependent pseudoranging anomaly on the most recently launched GPS satellite and similar anomalies observed on other GPS satellites.

With modernized GPS, civilian users will finally have access to full signals on additional frequencies, the L2C and L5 signals, and authorized military users, new M-code signals at L1 and L2. The new signals also come with a new dual-frequency ionosphere correction algorithm. This article, by authors at Charles Stark Draper Laboratory and the MITRE Corporation, describes why a new algorithm is needed, and how the new and old parameters are combined.

In this installment of the series, the author uses Matlab to illustrate key principles in receiver autonomous integrity monitoring.

This month’s column continues the discussion of prospective use of C-band frequencies for GNSS systems, addressing optimal design of signals, navigation message structure, and user equipment.

Bombs Away, Boot Sensors, ICD Access, Meet Up in Russia, China Tremblors, and The iPhone Catch in Tokyo…