1. Evolution of Global Positioning System Guidance Technology
Dustin Holden

2. Topics of Discussion What is GPS and how does it work?
Where did GPS come from?
When did Ag GPS become available?
How is Ag GPS used today?
How will Ag GPS be used in the future?

3. What is GPS and how does it work?
GPS in general
How does it work

4. What is GPS and how does it work? GPS in General
24 Rockwell International Navstar Satellites
Altitude: 12,550 miles
Weight: 1900 lbs (in orbit)
Orbital Period: 12 hours
Planned Lifespan: 7.5 years
5 Ground Based Monitoring Stations
United States: Hawaii, Colorado
South Atlantic: Ascension Island
Indian Ocean: Diego Garcia
Marshall Islands: Kwajalein

5. What is GPS and how does it work? How it works
Triangulation
Measure distance using travel time of radio signals
Timing
Location of the satellites
Delay error correction

6. Where did GPS come from? Child of Cold War Department of Defense
Navstar system developed in early 1970’s
First six Navstar satellites launched
Balance of 24 NAVSTAR satellites were launched in 1980’s
First civilian products appeared in mid 1980’s
In 1995 the system reached full operational capability

7. When did Ag GPS become available?
1992 First agricultural aerial guidance system
1993 First compact light bar
1995 First USCG Beacon DGPS receiver targeting agriculture
1997 First GPS receiver for agriculture with choice of correction
1999 First Real-Time Kinematic (RTK) receiver for agriculture
2003 First non-laser automated leveling system for agriculture

8. How is Ag GPS used today? Precision Tillage / Planting Spraying
Harvesting
Leveling

9. How is Ag GPS used today? Precision Tillage / Planting
Light Bar Guidance
Auto Steer
Terrain Correction

10. How is Ag GPS used today? Spraying
Green Seeker
Swath Control Pro

11. How is Ag GPS used today? Harvesting
Yield Monitoring

12. How is Ag GPS used today? Leveling
Differential GPS
Real Time Kinematics GPS

13. How will Ag GPS be used in the future?
Fully automated farming?

14. References http://www.trimble.com/index.aspx