Opportunities and Limitations of Automatic Steering Technologies. Nyle Wollenhaupt Advanced Technology Solutions Agronomist

Transcription

1 Opportunities and Limitations of Automatic Steering Technologies Nyle Wollenhaupt Advanced Technology Solutions Agronomist

2 So where do we start? We start at the beginning.

3 When we didn t have GPS-assisted guidance

4 Tape on the Window Posts

5 Counting Rows and Using Foam Markers

6 Light bar Guidance

7 Assisted Auto Steering

8 Terminology (confusion) Visual Guidance (Operator Steering) Fieldstar - Litestar Deere Parallel Tracking RHS - Outback Trimble EZGuide Steer Assist (Automatic steering) Challenger Auto-Guide Beeline Arro, B2000 Deere AutoTrac Trimble Autopilot IntegriNautics - AutoFarm

9 Guidance Types and Terminology Visual indication Operator steers Light bar and/or graphical display unit (like navigation system in car) Assisted steering Motor attached to a steering wheel steers the tractor automatically Automatic Guidance Automatic steering with fully integrated steering system

10 Why Auto Guidance? AUTO-GUIDE Benefits Reduces overlap/underlap Reduces inputs such as chemical over dose/under dose Improve weed control Improve seed/plant establishment Reduce distance covered Fuel used Implement wear Time Reduce driver fatigue Driver can concentrate on task being carried out Increased productivity

11 Calculated Example of Steering Benefit (Corn) 1,000 acre farm with a benchmark overlap/skip of 10 percent. (So operator will be farming 1,100 acres) Add 10% (Corn Production) $3.73 per acre Equipment Operation Cost $1.97 per acre Fuel (Jan at $3.97 diesel per gallon and 12 gal. per hour usage at 24 acres per hour) $56.25 per acre $ per ton) Potash $84.38 per acre $ per ton) NH3 $80.00 per acre (32,000 $ per bag) Seed Corn $6.00 per acre (24 $32.00 per gallon) Roundup $1.23 per acre (hired help) time spent on the extra 100 acres $ per acre additional cost of operation/production Totaling $23, in additional costs. Still only harvesting 1,000 acres of crops.

12 Auto-Guide Common Terms Antenna Offset The distance between the antenna and center of the machine or swath width perpendicular to direction of travel Base Station A fixed-location GPS receiver that provides differential corrections to roving vehicles Convergence/Convergence Time When a receiver is first powered up, it is the process of the receiver to acquire/converge to its true position. Convergence time is how long it takes the system to acquire its true position. Cross Track (xtrack) The perpendicular distance from the current machine position to the wayline Dilution of Precision (DOP) The measure of the contribution of satellite geometry to the uncertainty in a position fix. Firmware A computer program embedded permanently in a hardware device. NAVSTAR (Navigation Satellite Timing And Ranging) NAVSTAR consists of 28 functioning U.S. satellites that orbit the earth and provide precise, worldwide positioning and navigation information, 24 hours a day. There are actually 31 satellites in orbit System requires a minimum of 24 satellites to function

13 Auto-Guide Common Terms Portable Base Station A base station that can be easily moved and can determine the new location for use in a DGPS system. Real Time Kinematics (RTK) A relative positioning procedure where carrier phase measurements (or corrections) are transmitted in real-time from a reference or base station at a known location to one or more roving vehicles Repeatability The ability to save and use stored settings, such as the swath width of an implement, or specific dimensions of a field. Roll Bias Calibrates the software that interacts with the DMU to improve accuracy. Is required at all levels, but most important in decimeter and centimeter accuracies. (This function does not calibrate the DMU) Roving Vehicle (Rover) A moving vehicle, such as a tractor, that is equipped with a GPS receiver, such as the steering controller. Signal Lag The age of the correction measurements, or the time between the measurements being made and the measurement being used. SLOP (Strategic Lateral Offset Procedure) The measure of how close a GPS position estimate is to the true location

14 GPS (Global Positioning System) Created by the US Department of Defense Industry currently works with 28 Operational Satellites Accurate to around +-15m Used to calculate position Glonas (Russian satellite constellation) Galileo (European satellite constellation)

15 GPS and DGPS What is DGPS? Differential Global Positioning System DGPS is used to improve the accuracy of the GPS system It calculates the error in the GPS position measurement It then sends this correction information to the vehicle

16 DGPS How it works DOD Satellite DOD Satellite DOD Satellite DOD Satellite Commercial Satellite DOD Satellite 1. Satellites send signal to rover vehicle 2. Satellites send signal to differential station 3. Differential station calculates satellite errors 4. Transmits correction to fixed commercial satellite 5. GPS unit on machine receives corrected signal 6. Rover uses its own GPS data, combined with the commercial satellite data to produce an accurate measurement solution. Reference Station at known Point (X) Up-link station Calculates GPS Position errors (= X Y)

17 Mobile Base Station How it works DOD Satellite DOD Satellite DOD Satellite DOD Satellite DOD Satellite 1. Satellites send signal to rover vehicle 2. Satellites send signal to base station 3. Mobile Base Station transmits GPS correction measurements and the fixed location of base station to the rover 4. Rover uses its own GPS data, combined with the GPS corrections data and the fixed base station data to produce a highly accurate measurement solution.

18 GPS and DGPS requirements GPS tells the machine where it is. Survey Quality GPS receivers need at least 5 satellites all the time DGPS makes it more accurate A connection to the DGPS source whether satellite or local base is required at all times. Lose EITHER of these and guidance stops.

19 Available Correction Sources Government Satellites (Currently using the 28 Dept. of Defense Satellites) WAAS (U.S. free signal) CDGPS (Canadian WAAS) EGNOS (European WAAS) MSAS (East Asia WAAS) Commercial Satellites OmniStar (VBS, XP and HP) Racal/Navcom (Starfire 1, Starfire 2) Suppliers of Racal LandStar satellite-based DGPS service in North America. RTK Local Base Station

20 Position of Seed to Fertilizer Source: Nutra-Flo Company

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22 How is Accuracy Defined? Static Accuracy Measured over 24 hours Accuracy measurement to measure repeatability. Appropriate Application Example Pass-to-pass Measured over a period of 15 minutes Appropriate Application Example

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27 Auto-Guide Auto-Guide Accuracy Levels and GPS Sources Accuracy Description Correction Source Static Accuracy Dynamic Accuracy Annual Fees (USD) Sub-Meter WAAS 39" (100 cm) 10" (25 cm) $0.00 CDGPS 39" (100 cm) 10" (25 cm) $0.00 OmniSTAR VBS 31" (80 cm) 8" (20 cm) $ Decimeter OmniSTAR XP 10" (25 cm) 5" (12 cm) OmniSTAR HP 4" (10 cm) 2" (5 cm) $ $1, Centimeter Local Base Station (RTK) 0.8" (2 cm) 0.8" (2 cm) $0.00

28 System Components

29 Top Dock Installation

30 Mobile Top Dock (6-axis) GPS Antenna GPS receiver DMU

31 GPS Receiver and GPS Antenna GPS Receiver Processes signals from: GPS Satellites DGPS Satellites/RTK DMU Combined signals generate true location GPS Antenna GPS Antenna receives the GPS and OmniSTAR correction information Improved antenna for better satellite tracking with less chance of drop out.

32 Top Dock - DMU Dynamic Measurement Unit 6 axis Standard in all Mobile TopDocks Measures Roll, pitch, yaw (X,Y,Z) Measures angular movement and acceleration in each axis Fast update of 100hz and measurement in 6 axis ensures outstanding terrain following.

33 DMU Roll Dynamic Measurement Unit GPS antenna Position according to satellites Tractors actual position χ φ Amount of correction needed Roll Tractor angle

34 Yaw DMU Yaw

35 Pitch DMU Pitch

36 TopDock Freewave Radio (for use only with an RTK base station) The Freewave Radio, with the external antenna, is the device that communicates with the RTK base station for centimeter accuracy.

37 Mobile Base Station (only for use in centimeter systems) The mobile base station can be mounted on a portable tripod if repeatability is not desired. The mobile base station should not be mounted directly on to a grain leg, radio tower or any other tall structure. The sway of the structure will create a sway in the wayline. Reducing the desired accuracy of the system. The base station should be mounted on a permanent/semi permanent structure (i.e. anchor post or similar structure) with open visibility to the southern sky. If the operator wants to gain visibility with a higher trajectory, an external antenna should be used and can be mounted on towers, grain bins, etc.

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39 Satellite Predictor AUTO-GUIDE allows the user to see times in the day when the number of GPS Satellites maybe low or the quality of the GPS Satellite information is good or bad. The user can maximize their work by knowing when a time of poor GPS performance is approaching The user can trouble shoot their system if the steering accuracy has become questionable.

40 Guidance Patterns Parallel Contour Center Pivot

41 Technology Incompatibilities

42 How do we all get along? ISOBUS 11783

43 ISO BUS Value is: To take you from this To this

44 The Pioneer Hydraulic Coupler enabled the farmer to mix and match his equipment brands. So that you can go to this...

45 Implement Offset The implement offset is designed for implements that pull with a different width at either side of the machine, whether by operator design or through equipment wear and tear. If the offset is not taken into account then you will get an overlap and missed areas of ground. AUTO-GUIDE allows the user to compensate for this so that the work will match up correctly. Center line of Implement Implement Offset value Center Line of Tractor

46 Summary Auto steering is accomplished with the integration of a variety of technologies. Determine your application precision and accuracy requirements. Upgradeability? Work closely with the equipment manufacturer. Look for factory ready and factory installed applications.

47 THANK YOU