An introduction to GPS technology GPS Basics Acknowledgements
An introduction to GPS technology GPS Basics
Acknowledgements Thank you to the University of New Hampshire Cooperative Extension Program for providing these materials!
Global Positioning System �Developed by the US Department of Defense �Satellite-based �Designed to provide positioning and timing information: 24 hours/day, 7 days/week Under any weather conditions Anywhere in the world �Three components – space, ground, user
1. Space Component � 24 satellites in the US constellation � Orbit every 12 hours at 12, 550 miles � 4 satellites in each of the 6 orbital planes � Transmit a uniquely coded radio signal � Equipped with onboard atomic clock UNH Cooperative Extension 2008
2. Control Component � Ground-based monitoring and upload stations http: //www. gps. gov/systems/gps/control/ � Control orbit and timing information
3. User Component �Both military and civilian users �Navigation and positioning applications on land, sea, in the air and in space http: //usmilitary. about. com/od/armyweapons/a/gps. htm
How does GPS work? 1. The receiver picks up the signals from the satellites 2. Uses the signal travel time to calculate distances to the satellites 3. Triangulates to determine position of the receiver
How does GPS work? 1. The receiver picks up the signals from the satellites Space Earth UNH Cooperative Extension 2008
How does GPS work? . = 13 ec , 000 5 s 07 0. mile s Travel time of signal from satellite used to calculate distance 00 0 sec , 0 14 ile m s 0. 07 2. 0. 0 59 s Space Earth ec. = 11, 00 0 m iles 0 miles . = 12, 00 0. 065 sec UNH Cooperative Extension 2008
How does GPS work? 3. Receiver triangulates to determine position of the receiver UNH Cooperative Extension 2008
How does GPS work? 3. Receiver triangulates to determine position of the receiver UNH Cooperative Extension 2008
How does GPS work? 3. Receiver triangulates to determine position of the receiver UNH Cooperative Extension 2008
How does GPS work? 3. Receiver triangulates to determine position of the receiver UNH Cooperative Extension 2008
How does GPS work? 3. Receiver triangulates to determine position of the receiver You are here! UNH Cooperative Extension 2008
Geodetic GPS Receivers �Capable of sub- centimeter accuracy �Bulky, expensive �High-precision applications such as surveying, geodetics
Mapping GPS Receivers �Capable of 10 meter accuracy (<1 meter with differential) �Light-weight, portable, less expensive �Resource mapping and navigation applications
Handheld GPS Receivers �Capable of 10 meter accuracy (capable of <3 m with differential) �Light-weight, cheap! �Navigation applications and basic mapping applications.
Choose your weapon… Geodetic 1. High quality surveying of fixed positions Mapping 2. Collection of GPS data with large amounts of auxiliary data and strict data quality control Handheld 3. Collection of GPS data with good data quality for more limited budgets
Navigation Don’t forget your map and compass!
This GPS presentation includes slides from Trimble Navigation and Tom Luther, USDA Forest Service.
Questions?
- Slides: 21