Latest Advances in GPS Technology

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Latest Advances in GPS Technology

• Randy Taylor
• Extension Engineer, Machinery Systems
• Biosystems and Agricultural Engineering

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GPS Technology

• Precision Ag Technology
• allows management at a small scale without
  sacrificing efficiency gained from owning large
  equipment.

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Precision Ag Technologies

• Yield Monitors
• Guidance Systems
• Control Systems
• Sensor Technology
• Remote Sensing
• GIS Advancements

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Yield Monitors

• Yield monitors are a commercially accepted
  commodity
• They will become standard equipment on new
  combines by default
• Key uses are
• Diagnosing Crop Production Problems
• On-Farm Research
• Determining Spatial Yield Potential

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Guidance Systems

• Lightbars are becoming almost a standard item for
  most farmers and applicators.
• Autosteer is experiencing rapid acceptance and
  new or improved products are flooding the
  marketplace.

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Light Based Interface

• Uses lights to indicate what the operator should
  do to maintain the desired path

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Image Based Interface

• Uses an image of the vehicle and an indication of
  where the vehicle should be
• Some models have a moving road type of display
• Combination systems

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Automatic Steering Technology

• We need a precise (and maybe accurate) and stable
  GPS navigation signal (pass to pass).
• We add a computer controlled electro-hydraulic
  steering box.
• An inertial measurement device to compensate for
  yaw is nearly essential.
• Pitch and roll should be considered.

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Accuracy v. Precision
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Inertial Sensors

• Combining DGPS with Inertial Measurements
• Inertial sensors measure pitch, roll, and yaw
• Updates 10-20 times faster than DGPS
• Steering is driven by a combination of the two
  signals
• Benefits
• Higher travel speed
• Maintains straight line on side hills and
  terraces
• Continues to steer through short signal
  interruptions

.
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Operator Tasks

• Auto steering systems frees the operator to do a
  better job of monitoring equipment functions
• Sprayers
• Planter operation
• Harvesting
• Or maybe just talking on the phone or reading a
  book
• Auto steer makes an inexperienced driver (not
  operator), experienced

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Auto Steer for Combines
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GPS Static Accuracy

• Dual frequency signals (Deere SF2 and OMNISTAR
  HP) easily provide static horizontal precision
  less than 1 foot.
• This typically translates to pass-to-pass
  accuracies less than 4 inches.
• GPS accuracy is not all that matters vehicle
  dynamics is important

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GPS Signals and Applications

• WAAS
• Beacon
• Single Frequency
• Dual Frequency
• RTK

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Selection Criteria

• Operator Steered
• Auto Steer
• Expansion/Upgrades
• Coverage Maps
• Boom Section Control

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Control Systems

• Rate controllers are accepted items on sprayers
  and fertilizer applicators
• These are being integrated into ag vehicles
• Recent Advances
• Combine feedrate control
• Automatic boom section control
• Boom height control

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Real Time Coverage Maps
Are you sure you didnt miss a spot? Having a
coverage map, while you are still at the field is
a great asset.
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Automatic Boom Section Control
For a lot of fields in Oklahoma, more sprayer
overlap is due to point rows and irregular fields
than steering errors.
Can the system integrate with a sprayer rate
controller to turn off boom sections that are
overlapping previously sprayed areas?
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Combine Feedrate Control Project

• Soft white wheat was harvested on July 27-29,
  2004 near Murtaugh, Idaho
• Five experienced operators

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Combine

• John Deere 9860 STS combine
• 36 foot wide draper header

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Operating Characteristics

• 130 bu/ac irrigated wheat
• Baling straw
• Straw chopper disconnected
• Low cutting height

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Conclusions

• Automatic feedrate control increased
• Material capacity 5.5 across all operators.
• Speed by 0.5 km/h (0.3 mph) or 16
• Assuming yield of adjacent passes were similar,
  speed is a better indicator of potential
  improvement.

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Control Algorithm
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Sensor Technology

• Greenseeker
• N-management
• Veris Technologies
• Soil EC Sensor
• Mobile Sensor Platform
• w/ pH Manager

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Remote Sensing

• It will be the savior of precision ag
  technologies
• There have been some niche applications, but
  widespread adoption has not occurred

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GIS Advancements

• Integration of production and financial records
• Data dictionaries
• Standardized naming

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Precision Agriculture

• Mechanization of agriculture was considered one
  of the top ten engineering achievements of the
  previous century
• The incorporation of electronics and control
  systems will be one the next great achievement in
  ag equipment

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Remember, its
Evolution not Revolution
Randy.Taylor_at_okstate.edu