Processing GPS Data with Neural Networks
Sep 1, 2007
By:
Rodrigo F. Leandro, Carlos A.U. da Silva, Paulo C.L. Segantine, Marcelo C. Santos
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Primarily developed for computing applications, such as pattern recognition, neural networks have been adapted for use in several fields of science, including geodesy. Those adaptations are needed because usually the situations and problems encountered in computer science are different from those in other fields. Geodesy is no exception.
In Which the Real Money in GPS Is Unearthed
Jul 1, 2007
By:
Stephen Colwell
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GPS products sold in the survey and construction sector range from $1,000 to $125,000, furnishing high gross margins. We explore the business of this industry segment, its key players, and their relationships with providers and vendors.
Mar 1, 2007
By:
Taher Hassan, Cameron Ellum, Sameh Nassar, Wang Cheng, Naser El-Sheimy
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While photogrammetry is often used as a mapping tool on its own, GPS can aid the technique by supplying accurate coordinates for digital cameras. In turn, photogrammetry can come to the aid of a GPS/INS positioning system by bridging gaps in GPS/INS positions, which frequently occur in urban environments.
Feb 1, 2007
By:
Rodrigo F. Leandro, Marcelo C. Santos
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When processing GPS data, we should not only try to model the deterministic part of the measurements; we should also try to account for their stochastic behavior, which is possible through use of the covariance matrix. Here, the authors present an empirical approach for building the covariance matrix of observations, with the ultimate goal to improve the quality of GPS data processing.
Jan 1, 2007
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This update to a seminal article first published here in 1998 explains how statistical methods can create many different position accuracy measures. As the driving forces of positioning and navigation change from survey and precision guidance to location-based services, E911, and so on, some accuracy measures have fallen out of common usage, while others have blossomed. The analysis changes further when the constellation expands to ombinations of GPS, SBAS, Galileo, and GLONASS. Software scripts, provided online, help bridge the gap between theory and reality.
Jan 1, 2007
By:
Angelyn W. Moore
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The IGS was established in 1994 in order to provide the highest quality GNSS data and products in support of Earth science research, multidisciplinary applications, and education. It was and is still the aim of the IGS to advance scientific understanding of the Earth system components and their interactions, as well as to facilitate other applications benefiting society.
Seeking Support for High-Precision Networks
Oct 1, 2006
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Already adopted by many countries, real-time networks (RTNs) can be a boon to the public and private sectors. In the U.S., the On-Grid initiative seeks to bring together local and regional RTN developers to pool resources so that high-precision real-time GNSS networks can benefit the surveying, scientific, and communication sectors, among many others.
Assessing Real-Time Kinematic Performance
Sep 1, 2006
By:
Don Kim, Luis Serrano, Richard Langley
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A circularly polarized antenna's phase depends directly on the antenna's orientation with respect to the signal source. As a result, the observed carrier phase depends on the relative orientation of the transmitting and receiving antennas as well as the direction of the line of sight between them. Changing the receiver antenna orientation changes the reference direction and thus the measured phase.
Knowing exact sea depths along the shoreline is critical to the U.S. Navy and other maritime efforts, but traditional measurement methods aren't always feasible. A new positioning and telemetry buoy equipped with GPS monitors critical water-level measurements far from shore in real time.
May 2, 2006
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Global Satellite Based Augmentation Systems (GSBAS) technology has presented us with an opportunity to greatly simplify the gathering of shore data used by the U.S. Navy and other mariners.
