GPS: Theory, Practice and Applications

Frederic G. Snider, R.P.G.

Course Description

The Global Positioning System (GPS) has revolutionized the fields of navigation, mapping and surveying. It is now routinely possible to know your location within about 10 meters (30 feet) anywhere in the world with inexpensive, hand-held commercial GPS receivers. It is also possible to use GPS for surveying at sub-centimeter accuracy, for control and monitoring of construction equipment and agricultural machinery, guidance of autonomous robots, and aircraft, vehicle and marine navigation.

This course provides an explanation of how the GPS system works, sources of errors, and methods used for improving the basic accuracy of the system, including Differential GPS. The wide range of GPS applications are reviewed and the main types and features of GPS receivers are discussed. The terminology used in manufacturer’s specification sheets is explained so you can compare various units. Finally, the course summarizes what you, the potential user, needs to understand in order to select the appropriate equipment for the intended use. As such, the principles and concepts presented here are equally useful to all types of engineers, constructors, architects, contractors, building inspectors, surveyors, scientists, and the general public.

The course outline is presented below:

• Introduction

• How accurate is GPS?

• Components of the GPS System
  • Space Segment
  • Control Segment
  • User Segment

• GPS Signal Characteristics

• GPS Data

• Determining Position using GPS
  • Determining Satellite Position
  • Almanac Information
  • Ephemeris Information
  • Measurement of Travel Time
  • Calculating Your Location

• Sources of Error
  • Atmospheric Effects in the Ionosphere and Troposphere
  • Satellite Clock Synchronization Error
  • Electronic Noise
  • Multipath Error
  • Uncertainty in Satellite Position (Ephemeris Error)
  • Intentional Degradation
  • Satellite Geometry

• Improving Accuracy - Differential GPS
  • Beacon
  • WAAS - Wide Area Augmentation System
  • LAAS - Local Area Augmentation System
  • Other Augmentation Systems
  • Real-time Correction of Multiple Receivers - Inverse DGPS

• Applications of GPS Technology
  • Recreation On Land, at Sea and in the Air
  • Public Health and Safety - Cell Phone Emergency Response
  • Public Health and Safety - Earthquake Prediction
  • Environmental Monitoring - Weather Forecasting
  • Environmental Monitoring - Wildlife Management
  • Commercial Applications - Fleet Management
  • Engineering - Monitoring the Dynamics of a Suspension Bridge
  • Engineering and Construction - Equipment Control and Monitoring
  • Agricultural Applications - Yield Mapping
  • Geosciences - Project EarthScope
  • Precision Navigation - Docking a Supertanker
  • Miles from Nowhere- Measuring Subsidence of Offshore Oil Platforms
  • Military Applications - Operation Desert Storm
  • Precise Timing Applications - High Voltage Energy Transmission

• Selecting a GPS Receiver
  • Sequential Receivers
  • Multiplexing Receivers
  • Parallel Receivers
  • Single Frequency, Dual Frequency, Carrier-Aided and Carrier-Phase Receivers
  • Intended Uses of the GPS System: Navigation vs. Mapping vs. Surveying
  • Area of Use: Marine vs. Land vs. Aviation
  • Portable, Transportable and Fixed Installation
  • Stand-alone vs. Integrated units

• Additional Factors to Consider
  • Accuracy Warning and System Status
  • Differential GPS Capabilities
  • Battery Life
  • Screen Display
  • Size and Weight
  • Antenna Configuration
  • Internal Maps
  • Waypoint Capabilities
  • Track Logging
  • Upload/Download Capabilities
  • Sunrise/Sunset Times
  • Odometer and Speedometer
  • Measurement Units
  • Pre-Loaded Database
  • Ruggedness/Waterproofing
  • Mounting Options
  • Other Features
  • Warranty, Service and Return Policy

• Conclusion

• Glossary

The course is approximately 40 pages long including one Table and 17 Figures. A glossary of the most commonly used terms and acronyms is provided as a reference document. A multiple choice quiz is available online.

This course includes a multiple choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the end of this course, you should understand the operation of the GPS system at a level sufficient to use GPS receivers for navigation and general positioning applications. You will be familiar with the meanings of the words and acronyms most commonly used in GPS literature, sales brochures, and manufacturer’s specification sheets. You will know what questions to ask potential vendors about their GPS equipment and how to decide what features you may need for your intended uses. You will also be familiar with the sources of error affecting GPS accuracy, how to improve the accuracy to the level you need, and the options available for accessing Differential GPS corrections.

Course Content

For your convenience, the course content is provided in three different formats. To study the course, you need to open or download one of the following course content documents.

GPS: Theory, Practice and Applications in HTM Format (88 KB).

GPS: Theory, Practice and Applications in MS Word Format (291 KB).

GPS: Theory, Practice and Applications in PDF Format (514 KB).

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

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DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.

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