GPS Applications for Precision Agriculture

1. by Randy Price Precision Farming Technologies Engineer and Specialist K-State Extension and Research Kansas State University GPS Applications for Precision Agriculture

2. Overview: Discuss Current GPS Systems in Agriculture Where things are going Height Modernization Uses in Agriculture Questions?

3. Largest Users of GPS Systems in Ag. - Guidance Systems: Automatically (or through visual cues) steers a tractor through a series of GPS points or down an A-B Line. Reduces driver fatigue. Allows for straighter rows. Reduces overlap and skips. Can skip a wet spot in field during planting/cultivating, work other side of field, then go back and plant or cultivate area that was skipped.

4. Different Types of Guidance Systems: Manual Guidance: Light Bars, PDA’s Auto-Steer Systems (performs the steering function for you): Computer and Operator Interface Hydraulic Valve Block GPS Antennae

5. Accuracies Available to Farmers: WAAS: OmniSTAR®: Similar to WAAS, but with carrier phase (L2) information. • RTK: • L1 and L2 with Base Station.

6. Pass-to-Pass Accuracies of Each System: WAAS – 6 to 12 inches – 5 ft. deviations year-to-year. OmniSTAR – 2 to 5 inches XP - +/- 8 inch year-to-year accuracy HP - +/- 4 inch year-to-year accuracy RTK – 1 inch or less and year-to-year

7. Portable Removable Units: All-in-one Less Wires Easy Installation Movable Available in: WAAS OmniSTAR® RTK Low Cost: $3000 to $6000

8. Built-in Units:

9. High-End Displays:

10. John Deere System - StarFire: Similar to others: SF1 – WAAS SF2 – OmniSTAR® RTK 3 month  6 month  12 month 24 month 36 month SF1 Free Free Free Free Free SF2 $400 USD $600 USD    $800    USD $1400  USD $2000  USD RTK No Subscription Needed

11. Ways to Get RTK Correction: Dealer or Farmer Owned Base Station: 30 to 15 miles radius Portable Base Station: 2 to 6 mile radius

12. Single Frequency (Non-RTK) Portable Base Station : Outback Guidance Baseline L1 Only Radio Beacon Guidance System in Tractor + Advantages/Disadvantages: Accuracy: 1 inch (from manufacturer)‏ Transmitter rated for 2.5 miles 2.5 miles

13. Many Other Systems:

14. WAAS Coverage of Kansas:

15. Light Bar / WAAS Guidance System - Light Bar Steering Only: • Set overlap correctly to manufacturers recommendations!

16. Pass-to-Pass Accuracy with Time

17. WAAS System - Long Term Offset from Original A-B Line: Day Offset from Original A-B Line (in.)‏ Maximum Difference (in.)‏ May 23 4.2 14.5 May 25 0.4 21.4 June 15 -0.3 17.5

18. Five Different RTK Systems: 68% 68% 95.4% 99.7% (Source: Adumchuk - University of Nebraska)‏

19. Pass-to-Pass Accuracy in Multiple Research Papers:

20. Pass-to-Pass Accuracy at Drawbar:

21. Cost of Guidance Systems:

22. Prices Going Down –New Products EzGuide 250 Lightbar $1500.00 Leica MojoRTK System: RTK and Base Station for $12,980

23. Where GPS is Going: Accuracies have been seen as quite good (by Farmers standards) Boom Control Turns off the boom sections as they pass over areas already sprayed Seed Control Turns off every 1 or 2 planter boxes when needed

24. Example of Planter Auto Shut-Off

25. Uses of GPS Height Modernization: • Government: • Watershed Mapping and Flood Plain Determination • BMP’s (best management practices) • Atrazine Measurement (Herbicide for Killing Weeds) • Sediment Loads • Individual Farmer: • Not as much • Relative heights usually good enough, but bench mark may be used to help determine sloped land and land type easier

26. Effects of Crop Growth: Rainfall Soil Texture Texture affected by land type, slope, topography

27. Topography: Topography has a significant impact on soil formation. It determines the runoff of water and the micro-climate which in turn affects vegetation. Water moving across the surface strips parent material away and deposits in low areas.

28. Other Sensors Seeing Success: NTech Greenseeker Tractor Mounted Hand-held Units Sees the Same thing as Remote Sensing Units Real-time

29. Kansas Wheat Field – 3% to 7% Slope

30. Nitrate Calibration Plots:

31. Flood Plain Soil: Ponding of water / soil texture may explain differences in vegetative index in this map

32. The Future: No-till becoming more widely used. Farmers doing much more spraying and at higher frequencies (more trips across the fields). High cost of inputs (fertilizer and herbicide) causing farmers to re-think spraying strategies and move towards variable rate applications. Land levelling could become more important as inputs become higher / crops worth more. Farmers will probably tend to use data that is easy to get first for developing prescription maps: Soil Texture Topography Relative (RTK measurement) Tilt sensors Preloaded map, etc. Greenseeker Etc.

33. Automated Tractors: Auto-turn around and guidance John Deere – ITEC Pro Implement Steering Trimble® GPS on Implement down to 1 inch. AutoFarm AFTracker

34. (Questions?)‏ The End

35. Things to look at: • Land leveling in flood prone areas • How much does this help versus cost • Disadvatnages? • Etc. • Cell towers for RTK correction (and internet)

36. To Replace Base Station: Need the Following: Must be close (for errors to be lowest)‏ Fast repeat time Sprayers travelling at 15-20 MPH need a GPS with an output rate or 5 to 20 Hz (real-time). Different Options: Cellular Internet, etc. Some Type of Standardized Transmitted Signal Similar to Coast Guard Beacon

37. Topography in Turn Determines Texture to Some Degree

38. Effect of topography and texture R2 Topography R2 Texture R2 Topography and texture Partial R2 for Clay+Silt CT R1 0.54 0.56 0.65 0.17 R2 0.32 0.52 0.63 0.42 R4 0.11 0.15 0.22 0.11 NT R1 0.27 0.3 0.41 0.19 R3 0.54 0.58 0.63 0.20 R4 0.74 0.79 0.83 0.34 • Contribution of texture is significant even after accounting for topography effect

39. Texture Triangle:

40. Other Uses of RTK: Variable Rate Spraying: Farmers are looking for those easy to find data Currently GPS location Next: Greenseeker / Remote Sensing Elevation / Topography Texture / Soils Maps Organic Matter

41. Payback Period: Estimate 30” off without guidance, better than 15” with WAAS alone. Typically, 2.5 yrs needed to pay off lower-end system (depending upon type of system purchased and number of uses per year). Ag Economics at Kansas State University http://www.agmanager.info/farmmgt/machinery/default.asp#Decision-Making%20Tools

42. Sensors Necessary as Better Accuracy is Desired: Tilt sensor probably the best sensor you can add on IMU (Inertial Mass Unit): Next best sensor Helps short term loss of GPS signal.

43. Website: www.bae.ksu.edu/precag Email: rrprice@ksu.edu Call: 785-532-2929

44. Possible Future Noise: We are in a minimum of energy disruption caused by sun spots, etc. This will continue to get worse to a maximum at 2012. Some worry for WAAS

45. Air Clutch on Planter System

46. Plant Height May Be Needed:

47. Example of Automatic Planter Shut-Off

48. On/Off Seeder Controls:

49. New Equipment: Leica MojoRTK Agricultural Guidance System RTK and base station for $12,980 Still need hydraulic actuator box for auto-steer

50. Parts of System: Guidance unit in a radio type mount housing Built into a radio unit Mounts up in the cab where the radio was located Includes AM/FM radio RTK accuracy (2 inch)‏ Portable Base Station Virtual Wrench Remote service capability via digital data cell network $12,980 price tag Note: Still need a steering kit!!!