True to its word origins, accuracy demands careful and thoughtful work. This article provides a close look at the differences between the precision and accuracy of GPS-determined positions, and should alleviate the confusion between the terms — making abuse of the truth perhaps less likely in the...More>>

The original GPS signals, and indeed most GPS signals including L5, utilize conventional pseudonoise (PN) signal code division multiple access (CDMA), some with both in-phase and quadrature-phase modulation. In the late 1990s, I generalized Manchester PN symbol-spreading by defining split-spectrum...More>>

The CPGPS 2010 Technical Forum on Satellite Navigation and Positioning will be held on August 18-20 in Shanghai, China, and is now seeking papaer submissions. The deadline for abstracts is June 1.More>>

In his 200th Innovation column, Contributing Editor Richard Langley takes a look at GPS by the numbers, getting a sense of how GPS works by examining the key numbers that govern its remarkable capabilities, from zero to pi and beyond. More>>

A team of Australian and U.S. researchers have integrated a ground-based system with GPS and INS to create a hybrid system that provides precise and accurate position information continuously in a variety of environments where GPS alone comes up short.More>>

The International GNSS Service (IGS) has further improved the quality of the products made available to the GNSS community. The accuracy of the Final GPS Orbits (available weekly with a delay of about two weeks) from IGS is now about 2 centimeters, based on an analysis of discontinuties between...More>>

A new approach to enhancing signal sensitivity combines the received signal power from multiple satellites in a direct-to-navigation solution. More>>

GPS receivers must deal with measurements and models that have some degree of error, which gets propagated into the position solution. If the errors are systematically different for the different simultaneous pseudoranges, as is typically the case when trying to correct for ionospheric and...More>>

Telltale signs of multipath are the fluctuations in the signal-to-noise ratios (SNRs) reported by some GNSS receivers. In this month’s column, the authors look at how an analysis of SNR values can be used to map the multipath environment surrounding an antenna so that models of multipath can be...More>>

Is there a viable alternative to real-time kinematic (RTK) positioning? In this month's column, we take a look at the technique of precise point positioning (PPP). How close is PPP to prime time?More>>