An introduction to GPS technology Acknowledgements Thank you to the University of New Hampshire Cooperative Extension Program for providing these materials GPS Accuracy what are your needs ID: 569119
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Slide1
Accuracy
An introduction to GPS technologySlide2
Acknowledgements Thank you to the University of New Hampshire Cooperative Extension Program for providing these materials! Slide3
GPS Accuracy – what are your needs?How accurate does your GPS data need to be? Is vertical accuracy important?
What are the ways to improve accuracy? Slide4
GPS Accuracy – signal delayAtmosphere, clock errors, multipath error
6 secs
4 secs
Idealized situationSlide5
GPS Accuracy – signal delayAtmosphere, clock errors, multipath error
6 secs
4 secs
4 secs uncertainty
real situation
6 secs uncertaintySlide6
GPS Accuracy – satellite arrangement
bad arrangement
good arrangementSlide7
GPS Accuracy – satellite arrangement Geometric arrangement of satellites in space
6 secs
4 secs
uncertainty
uncertainty
good constellationSlide8
GPS Accuracy – satellite arrangement Geometric arrangement of satellites in space
bad constellationSlide9
GPS Accuracy – differential correctionBase stations measure inaccuracies and send out correction signal
15m: typical handheld GPS accuracy without corrections3m: typical handheld GPS accuracy with correctionsWAAS: most common handheld correction
http://www.ae.utexas.edu/~shep/Slide10
Questions? Slide11
This GPS presentation includes slides from Trimble Navigation and Tom Luther, USDA Forest Service.