Notes

Slide Show

Outline

1	Accuracy of GPS-based Information Ben Koostra
2	GPS Classifications
3	Accuracy Assessment Absolute vs Relative Long-term vs Pass-to-Pass Static vs Dynamic
4	Absolute vs Relative
5	Static vs Dynamic
6	Dynamic Tests 25 ft. radius 13 sec/rev è 7 mph 24 hour duration
7	Example Test Results
8	Absolute vs Relative
9	Example Test Results
10	New Dynamic Test Facility
11	Track Layout
12	Track Hardware
13	Low-Cost Receiver A
14	Low-Cost Receiver B
15	A Practical Question I want to map the boundaries of my fields. Which GPS receiver (how expensive) do I need?
16	Typical Equipment Choices Garmin GPS76 handheld with external antenna WAAS differential correction Trimble AgGPS 132 USCG “Beacon” differential correction (50 km) Trimble AgGPS 214 RTK 0.5km max distance from base station
17	Field Test Configuration
18	Fields Mapped
19	Field Area
20	Test Conclusions Inexpensive receivers are sufficient for boundary mapping Area calculations within tolerable limits Boundary offsets are small and could be caused by differential correction methods
21	Mapping Concerns Tree canopy Reacquisition time Sampling interval – data rate
22	Field Corner
23	Summary Scrutinize accuracy specifications carefully (read fine print) Be careful when operating along field boundaries and other problem areas Be aware of drift and offsets between receivers Watch sharp maneuvers
24	"Ben Koostra" Ben Koostra Biosystems and Agricultural Engineering University of Kentucky www.bae.uky.edu