October 2006

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Receiver manufacturers and mobile phone designers face a plethora of wireless and GNSS standards in their efforts to build user equipment that employs telecommunciations networks to improve positioning accuracy and speed. As a result, telecom engineers are proposing a single, common standard for A-GNSS.

Born in the era of fallout shelters and school air-raid drills, the U.S. Emergency Broadcast System punctuated the anxieties of a Cold War. This commentary explores how that system lives on today and how a growing need for location information during emergencies  might be met by combining GNSS with mobile communications.

With the launch of the first modernized GPS Block IIR satellite in September 2006, GNSS product designers have an additional, fully open signal to use in their work: L2C. But the new signal also has different parameters than the L1 C/A-code signal available for the last 30 years. What does that mean to the people who are designing the correlators for new generations of GNSS receivers?

Several satellite-based augmentation systems for improving GNSS accuracy and integrity to assist aircraft approach and landings are well under way around the world. Their ground-based counterparts (GBAS) are also being developed. As this article reveals, Braunschweig, Germany, is becoming one of the focal points for GBAS activities in Europe.

Robustness, redundancy, availability, interoperability. Like FM radio, these are the qualities that make a GNSS system of systems such a desirable goal — for GNSS product manufacturers and location services providers, for end users, and for the nations building critical infrastructures and national security policies on space-based positioning, navigation, and time.

High-accuracy users of public GNSS reference archives don’t always have access to data that matches the high sampling frequencies needed for real-time kinematic techniques. This column proposes a method for interpolating GNSS observation residuals so as to produce data that can be used in kinematic applications.