Innovation

Innovation: Accuracy versus Precision

May 1, 2010By
In-8a

A Primer on GPS Truth
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 business of GPS positioning. read more

This article is tagged with and posted in Algorithms & Methods, Innovation

Innovation: GPS by the Numbers

April 1, 2010By
Inn_W

A Sideways Look at How the Global Positioning System Works
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. read more

This article is tagged with and posted in GNSS, Innovation

Innovation: Hybrid Positioning

March 1, 2010By
Figure 11. The electronic car used in the test.

A Prototype System for Navigation in GPS-Challenged Environments
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. read more

This article is tagged with and posted in Algorithms & Methods, Innovation

Innovation: Mobile-Phone GPS Antennas

February 1, 2010By
Figure 4. Sarantel miniature volute antenna

Can They Be Better?
We examine the antenna designs that provide GPS functionality to mobile phones and why most phones still do not provide GPS operation indoors. We also see what it will take to make them better. read more

This article is tagged with and posted in GNSS, Innovation

Innovation: Collective Detection

January 1, 2010By
I-T

Enhancing GNSS Receiver Sensitivity by Combining Signals from Multiple Satellites
A new approach to enhancing signal sensitivity combines the received signal power from multiple satellites in a direct-to-navigation solution. read more

This article is tagged with and posted in Algorithms & Methods, Innovation

Innovation: Improving Dilution of Precision

November 1, 2009By
Inn-T

A Companion Measure of Systematic Effects
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 tropospheric effects, these errors propagate into the receiver solution in a way that is fundamentally different from the way that random errors propagate. So in addition to dilution of precision, we need a companion measure of systematic effects. In this month’s column, we introduce just such a measure. read more

This article is tagged with and posted in Algorithms & Methods, Innovation

Innovation: It’s Not All Bad

October 1, 2009By
Mauna Kea GPS station MKEA, facing northwest

Understanding and Using GNSS Multipath
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 constructed to further minimize its effect. Also, although an annoyance for most GNSS users, it turns out that multipath has its positive points. read more

This article is tagged with and posted in Algorithms & Methods, Innovation

Innovation: One Year in Orbit

September 1, 2009By
DSCN2663_2

GIOVE-B E1 CBOC Signal Quality Assessment
GIOVE-B has been in orbit for just over one year. How well is it performing? In particular, what can we say about one of GIOVE-B's pioneering features: its E1 CBOC signal? In this month's column, we take a detailed look at a particular monitoring and assessment program set up to examine the GIOVE-B signals and discuss some of its initial CBOC results. The successful operation of this program bodes well for its use in future validation campaigns. read more