1. GPS and Precision Ag Technologies Is There Anything New? Kent Shannon Associate Director Missouri Precision Agriculture Center

2. GPS and Precision Ag Technologies Is There Anything New? GPS – Handheld (Low-Cost) Handheld Computers / Software GPS Guidance – Lightbars / Automatic Yield Monitors Sensors

3. Comparison of Various Recreational GPS Receivers 12 different recreational GPS receivers and a common DGPS receiver used for precision ag applications Compared to a Ashtech Z-Surveyor RTK GPS receiver with a 3-10 cm horizontal accuracy

4. Equipment Used for Data Collection Recreational GPS Receivers Used –Garmin – 7 models –Magellan – 2 models –Lowrance – 1 model –Teletype Compact Flash - WAAS –Navman – iPAQ sleeve - WAAS –Starlink Invicta 210 – DGPS receiver – Coast Guard Beacon

5. Equipment Used for Data Collection Garmin – 7 models –eTrex –Geko 201 - WAAS –eTrex Legend - WAAS –eTrex Vista - WAAS –GPS 76 - WAAS –Rino 120 - WAAS –GPS III Plus

6. Equipment Used for Data Collection Magellan – 2 models –Meridian GPS - WAAS –SporTrak Map - WAAS Lowrance iFinder - WAAS

7. Equipment Used for Data Collection Used PocketPC computers running VisualGPSce to collect raw NMEA data GPS receivers antennas mounted 1.88 m (74 in) apart from each other

8. Location for Data Collection 610 m 205 m RTK Base Station

9. Testing Pattern

10. Testing Pattern – Data Used for Analysis

11. Methodology for Data Collection Tests consisted of four time periods, each on a different day. –Two days of testing were conducted at 19.1 km/hr (11.9 mph) for 12 minutes –Two days of testing were conducted at 13.2 km/hr (8.2 mph) for 16 minutes Each time period receivers were tested using a Randomized Complete Block Design

12. Results and Discussion Relative Accuracy –95 th percentile value –Mean –Standard Deviation Ability to acquire WAAS correction and effect on relative accuracy

13. Note: Distance of 1.88 meters between GPS antennas taken into account LSD (0.05) = 2.34

14. Note: Distance of 1.88 meters between GPS antennas taken into account

15. LSD (0.05) = 1.21 Note: Distance of 1.88 meters between GPS antennas taken into account

17. Ability to Acquire WAAS Differential Correction

18. LSD (0.05) = 1.21 Note: Distance of 1.88 meters between GPS antennas taken into account

22. Conclusions Recreational GPS receivers perform well if WAAS differential correction is acquired in a straight line trajectory. There is some differences between recreational GPS receivers. Further work needs to be done, i.e. contours and using external antennas.

23. Yield Data Collection with “Low-Cost” GPS Receivers GPS76 with a GA27C External Antenna PC/Cigarette Lighter Combination Cable Holux GM-210 with Serial Connection and Cigarette Lighter Adapter

24. Corn Yield Map Made With Holux GM-210 GPS and Garmin GPS76 GPS

25. Palm OSPocket PC Handheld Computers Palm/Handspring –Zire, Tungsten, Treo Smartphones Sony –CLIÉ Compaq/HP - iPAQ 2215 Dell Axim X5 Toshiba – e750 ASUS – A620 ViewSonic – PCV37 Zayo – A600

27. Farm TracMate SST Stratus MapShots Pocket Crops Using Non-GPS Crop Recordkeeping Software on a PocketPC

28. Adding GPS for Crop Recordkeeping Integration of FarmWorks – TracMate and SiteMate

29. Adding GPS for Crop Recordkeeping SST Stratus and Summit

30. GPS Aided Guidance Lightbars

31. GPS Guidance Automatic

32. Yield Monitors and Controllers CAN Bus

33. Aerial Photograph from June 20, 2003 used for Development of Sidedress Nitrogen Application and Zones Developed

35. Greenness Ratio = Greenness of Nitrogen Sufficient Plots Greenness of Nitrogen Deficient Plots Nitrogen Rate = (-1249 + 1295 (Greenness Ratio)) x 0.89 Formula based on research by Scharf and Lory, Calibrating Corn Color from Aerial Photographs to Predict Sidedress Nitrogen Need Agron. J. 94:397-404 (2002)

36. Research Data from Scharf Used to Calculate EONR From Chlorophyll Meter from June 19, 2003 In Zone 4, in-field information from a SPAD meter was used to calculate a side-dress amount of nitrogen of 150 lbs/acre

39. LSD (0.05) = 11.12 LSD (0.05) = 10.66 LSD (0.05) = 7.76 LSD (0.05) = 8.00 LSD (0.05) = 4.60

40. Economics of the Nitrogen Management Strategies Used $0.28/lb for Nitrogen and $2.40/bu for Corn

41. Where are we going from here? Using the relationship of the amount of biomass to nitrogen need

42. Any Questions?