A Guide for Online Information About:

GPS Technology Overview

by Rick Prescott

The links contained on this page are intended to provide information on what the Global Positioning System is, how it works, and the various applications of this technology. GPS is funded and controlled by the U.S. Department of Defense (DOD). Although there are many thousands of civil users of GPS world wide, the system was designed for and is operated by the U.S. military. The nominal GPS Operational Constellation consists of 24 satellites that orbit the earth every 12 hours. These satellites provide specially coded signals that can be processed in a GPS receiver, enabling the receiver to compute position, velocity, and time. Four GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock. More detailed general information can be found at the following links.

Introduction to GPS Applications

This excellent overview of GPS compiled and authored by John Beadles includes information on the following subjects: GPS receiver reviews, GPS applications, GPS software, how-to library, and GPS equipment and services.

Global Positioning System Overview

On this site, you can see one of the most comprehensive on-line general GPS related sites in existenc, complete with optional graphics and compiled and authored by Peter H. Dana. Information is available on the following subjects: U. S. Department of Defense Satellite Navigation System, GPS positioning services specified in the federal radionavigation plan, GPS satellite signals, GPS data, position and time from GPS, GPS error sources, Geometric Dilution of Precision (GDOP), and Differential GPS (DGPS) techniques.

US Coast Guard

The U.S. Coast Guard is the home of the U.S. radio differential network. USCG monitors and is in charge of public relations for GPS. Many features include GPS, OMEGA, LORAN, safety, and other related sites. GPS portions include almanac, status news, and much more data.

JPO (Joint Program Office)

JPO provides the coordination of GPS and runs the ground and space segments. It contains an excellent overview of GPS, its segments, and equipment examples with lots of graphics.

GEO Community Web Site

The GeoCommunity web site is the premier resource for GIS/CAD professionals. It's a must visit for free downloads from over a terabyte of geospatial data sets, a high-powered industry-specific search engine, GIS industry news, discussion forums, classifieds, and software utilities.

United States Space Command, GPS Support Center 

This site is an excellent source for GPS calculated accuracies, DoP, availability, constellation performance, status, and much more. A wide variety of plots and charts explaining performance of the system can be found here.

NGS (National Geodetic Survey)

NGS provides information of GPS-related cartography, surveying, mapping, including CORS, ephemeris, orbital data, and much more.

The Geographer's Craft

The Geographer's Craft is a full course, including lecture notes, lab exercises, and glossary, from the University of Texas in Austin.

SEDS

SEDS (Students for the Exploration and Development of Space) now has an excellent space related site with many HOT links, including an internal search engine. You could spend a few days here.

The Great Globe Gallery

Many examples of different globe representations in many different formats can be found on The Great Globe Gallery's web site..

The following are links to associations, organizations, and educational institutions that are dedicated to both the advancement and integration of GPS technology into our everyday lives.

Institute of Navigation

The Institution of Navigation is a professional society dedicated to the advancement of the art and science of navigation. It hosts three meetings a year, including the worlds largest GPS meeting, ION-GPS. It also hosts Navtech Seminars and GPS tutorials.

University of Calgary

The University of Calgary is one of Canada's foremost educational institutions on GPS for geomatics engineering. Information on KIS conferences can be found on this web site.

University of New Brunswick

The University of New Brunswick is another of Canada's foremost educational institutions on GPS for geomatics engineering. This is a complete and detailed site, right down to the photo album.

Oddens's Bookmarks

More maps and mapping related data than you will ever know what to do with can be found on this site. This is a must for mapping applications.

GESS

The Department of Geography and Earth Systems Science at George Mason University provides many mapping applications, maps, and projects on its site.

Ordinance Survey

Great Britain's national mapping agency, Ordinance Survey, covers the production, maintenance, and marketing of a range of maps (digital and paper) and other related information.

University of Alberta GPS Working Group

The University of Alberta's GPS Working Group is involved in instruction, application, and research related to GPS technologies.

The Southern California Integrated GPS Network (SCIGN)

SCIGN is a collaborative project to install 250 permanent, continuously recording GPS receivers in and around the Los Angeles basin to provide accurate deformation information that will improve estimates of earthquake hazards.

The GPS Research Group

The GPS Research Group applies GPS technology to geodetic and atmospheric research.

GPS Operations

On this web site, you can find GPS operations that are being done at the United States Naval Observatory (USNO).

International GPS Service (IGS)

IGS provides GPS orbits, tracking data, and other high-quality GPS data and data products online in near real time to meet the objectives of a wide range of scientific and engineering applications and studies.

Government agencies hosting GPS information and programs:

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