Global Positioning System (GPS)

Definition

The Global Positioning System (GPS) is a satellite-based navigation system that enables users with GPS devices to determine their exact location on Earth’s surface. The system operates on a constellation of at least 24 satellites orbiting Earth, sending timed signals to GPS receivers. By calculating the time it takes for signals from at least four different satellites to reach the receiver, the device can triangulate and compute its precise geographic location.

Examples

1. Real Estate Appraisal:

   • An appraiser uses a GPS navigation device in their car to find a subject property.
   • Once at the site, the appraiser uses a handheld GPS device to determine the property’s exact geographic coordinates.
   • The appraiser returns to the office, uses those coordinates to locate the property on Google Earth, and obtains a satellite view of its topography.

2. Urban Planning:

   • Urban planners utilize GPS to map out new developments, ensuring accurate positioning of infrastructure such as roads, utilities, and buildings.

3. Field Surveys:

   • Surveyors use GPS devices to measure land boundaries and create detailed maps for construction projects or legal documentation.

Frequently Asked Questions (FAQs)

What is the accuracy of GPS?

• Modern GPS devices typically offer accuracy within a few meters under ideal conditions. High-end devices used for scientific purposes can achieve sub-meter accuracy.

Can GPS work indoors?

• GPS generally performs poorly indoors or in areas with signal obstructions. Indoor positioning systems or assisted GPS (A-GPS) can be used to enhance accuracy in such environments.

How does GPS benefit real estate?

• GPS aids real estate by providing precise property locations, aiding appraisals, surveying, mapping land parcels, and developing geographical information systems (GIS).

Are all GPS devices compatible with each other?

• Most GPS devices adhere to standard protocols, ensuring broad compatibility with different GPS-enabled services and applications.

Related Terms

• Geographic Information System (GIS): A system designed to capture, store, manipulate, analyze, and manage spatial or geographic data. GIS can integrate GPS data for map creation and spatial analysis.
• Triangulation: The process of determining the location of a point by forming triangles to it from known points. In GPS, signals from multiple satellites are used for triangulation.
• Satellite Navigation: A system using satellite signals to provide geo-spatial positioning, allowing small devices to pinpoint locations on Earth.
• Assisted GPS (A-GPS): Enhances the performance of standard GPS in mobile devices by using network resources to locate and utilize satellites faster.

Online Resources

• NASA’s Galaxy of GPS Knowledge: Information on how GPS technology was developed and its various applications.
• U.S. Geological Survey GPS Overview: An overview of GPS technology and its geological applications.
• Garmin GPS Academy: Garmin’s learning center offering resources and tutorials on using their GPS devices effectively.

References

• “Understanding GPS: Principles and Applications” by Elliott D. Kaplan and Christopher Hegarty.
• “GPS for Land Surveyors” by Jan Van Sickle.
• “Global Navigation Satellite Systems: Insights into GPS, GLONASS, Galileo, Compass, and Others” by Artem I. Borodin.

Suggested Books for Further Studies

• “GPS Made Easy” by Lawrence Letham: A user-friendly guide on using GPS technology for various applications, including real estate.
• “Introduction to GPS: The Global Positioning System” by Ahmed El-Rabbany: A comprehensive primer on GPS, covering its fundamental principles and practical uses.
• “The Global Positioning System & Inertial Navigation” by Jay A. Farrell and Matthew J. Barth: Details the integration of GPS with inertial navigation for enhanced accuracy in various fields.

Global Positioning System (GPS) Fundamentals Quiz