Vehicle guidance From horses to GPS

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Vehicle guidanceFrom horses to GPS

• Jorge Heraud and Arthur Lange
• Trimble Navigation Ltd.
• June 2009

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The greatest challenge

• This generation of engineers and scientists will
  need to solve the toughest of problems ever
  encountered
• Energy shortage, Food shortage, Fresh water
  shortage, Global Warming
• Today more than ever before, Science holds the
  key to our survival as a planet and our security
  and prosperity as a Nation Barack Obama, Dec 20,
  2008
• I will show you, how previous generations rose to
  tough technical challenges

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(No Transcript)
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For today

• History of automatic steering
• Modern automatic steering
• Why GPS guidance so widely used

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History of manual guidance as seen through patents
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1870 - row marker for single-row horse powered
plowing
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1876 - Two-row corn planterwith row marking
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1953 Cabled double row marker1963 Cabled
folding row marker
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1921 Looking through the tractor1951 Front
mounted visual aid
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1951 Double hood mounted visual aid1990
Windshield and hood visual aid
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1976 Visual aid for implement guidance
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1970 Electronically marking system
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1987 Paper tissue marking system

• Tissue paper roll goes here

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History of automatic guidance as seen through
patents
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1885 "Furrow pilot
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1914 Improved furrow follower
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1949 Movable furrow follower
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1941 Spiral guidance
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1970 Safety stopping mechanism
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1976 Automatic system to steer harvesters
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1976 Crop feelers using strain gauges
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1996 Rocking sensors boundary detection 1998
Ultrasonic sensor boundary detection
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Modern Automatic Steering systems
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GPS based systems are now the norm for automatic
steering

• Manual GPS started around 1995
• Automatic GPS started in 1997
• Hydraulic, steer-by-wire, CAN, electric motor

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Why is GPS guidance so widely used
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GPS guidance doesnt accumulate errors
Re-start
Skips
Overlaps
Fixed pass guidance GPS, strings when planting
orchards
Prior pass guidance Visual aides, row markers,
foam markers
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Convenient embodied technology with a quick
payback

• Savings of 10 on skips and overlaps
• Just drive to get the savings
• Operate at faster speeds, at night
• Reduced fatigue, convenience
• All field patterns
• All terrains
• Facilitates / enables new practices
• Strip till, band spraying, drip tape, strip-
  intercropping
• Reduces need for additional on farm labor
• Performance not skill dependent
• Grandpa is planting again

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GPS guidance enables precision Ag
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Automatic section control

• Automatic section control minimizes overlap and
  slow down

Reaction time
Headland
Overlap area
Manual shutoff
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Automatic section control

• Field NOT Using Air clutches

• Field Using Air Clutches

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Ag Journey
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Ag Journey
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Ag Journey
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Ag Journey
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Ag Journey
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Ag Journey
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Innovation
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Value Proposition
Automated Guidance Implement Guidance Variable
Rate Overlap Switching Data Transfer
12.0 3.0 7.3 4.6 ?
Total Savings
12.0
15.0
22.3
26.9
gt26.9
Engineers working on Automatic Guidance and
Precision Agriculture have increased productivity
by 26.9 in the last 14 years
The Ag Engineering community is ready for the
next challenge
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GPS and GNSS review
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GPS
Each SV transmits signals and data that are
received by the rover (user equipment). This
allows the rover to measure the distance to each
SV. These are the Pseudoranges In
3-dimensions, it takes 4 Pseudoranges to
calculate the position since time at the rover is
also a variable. A GPS receiver measures
Position, Time, and Velocity. The velocity
measurement is independent of the position
measurement and is based on the Doppler.
1. Atomic standards in satellites (4 needed)
2. Satellites transmit ranging signals orbit
info
3. Position, velocity, time computed from
range measurements and data message
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Increasing GPS accuracy
Four or more satellites viewed by two receivers
Base station - a high performance GPS receiver
placed in a fixed location whose position is
accurately known. The GPS measured position is
compared sec by sec against the known position,
and an error calculated. This error is assumed
to be the same error at the rover, and is sent to
the rover as a differential correction.
Rover adds error to its measured position to
obtain the corrected position
Error data is sent to rover with radio
Autonomous GPS 2 meters Differential GPS
0.5 meters RTK (5 SVs) 0.02 meters
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GPS Operational GPS Satellites

• Current Satellites
• 25 IIA/IIRs
• 10 Final Clock
• 2 will be decommissioned Spring 09
• 6 IIR-Ms (L2C)
• Launch planned Mar 09, Aug 09 (with L5 enabled)
• Future Satellites
• GPS Block IIF (L5)
• IIF-1 launch Oct 2009
• GPS III
• Launch 2014
• 24 satellites by 2021

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GPS Modernization Benefits

• GPS IIR-M L2C (1227 MHz)
• Improved L2 signal measurement slight
  improvement to IONO measurements
• GPS IIF L5 (1185 MHz)
• Improved RTK Acquisition
• Improved DGPS accuracy
• Higher chipping (107)
• Better ionosphere modeling
• Increased Power Level
• Improved operation under canopy
• Better SNRs
• GPS III
• L1C designed for interoperability with other
  systems (Galileo, for example)

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GPS Accuracy and Solar Cycle
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RTK Performance with low and high Ionosphere
disturbance
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E-W vs. N-S Accuracy
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Global Navigation Satellite System (GNSS)

• GPS
• Space Based Augmentation Systems (SBAS)
• WAAS, EGNOS, MSAS, GAGAN, GRAS, CDGPS
• OmniSTAR, Starfire
• GLONASS (Russia)
• QZSS (Japan)
• Compass (China)
• Galileo (EU)

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Augmentation Systems for increased accuracy

• Space Based Augmentation Systems (SBAS)
• WAAS - Wide Area Augmentation System (US)
• EGNOS - European Geo Stationary Navigation
  Overlay System (EU)
• MSAS - MTSAT Satellite-Based Augmentation System
  (Japan)
• GAGAN (GPS Aided GEO Augmented Navigation) India
• GRAS (Ground Regional Augmentation) AUS
• Canadian DGPS
• OmniSTAR XP/HP
• StarFire

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Augmentation Systems for increased accuracy

• Ground Based Augmentation Systems
• NDGPS MF Beacons (sub-meter)
• HA-NDGPS MF Beacons (4 sites are now
  transmitting) 10-20 cm service (similar to
  OmniSTAR XP/HP)
• RTK Base Stations local radio transmitters
• RTK VRS Networks internet and cell phones
• Trimble Terrasat
• CORS (Continuously Operating Reference Station)

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U.S. GPS Augmentation Update

• Wide Area Augmentation System (WAAS)
• Expanding monitor stations into Canada and Mexico
• Two SVs at 135 and 138 for North America
• WAAS satellites provide L1 and L5 ranging
• WAAS provides DGPS corrections including IONO
  modeling
• Nationwide Differential GPS (NDGPS)
• DOTs Research and Innovative Technology
  Administration, funding of NDGPS is still a
  concern

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European Geostationary Navigation Overlay Service
(EGNOS)

• Status
• AOR-E (120) and IOR-W (126)
• Initial Operations
• ARTEMIS (124)
• Testing
• Recommended reading
• EGNOS for Professionals web site WWW.ESA.INT

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Benefits of Additional GNSS

• Availability
• More Satellites mean better availability in
  difficult environments (Land Leveling in the
  Mississippi Delta)
• Some system upgrades will have stronger signals
• Reliability
• More Satellites mean no outages even with
  individual satellite failures

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GLONASS the Russian GPS

• Currently (January 13, 2009) 16 Operational SVs
• Goal is to have a full constellation of 24 SVs by
  2010

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GLONASS and RTK

• Using GLONASS SVs with RTK will help
• Initialization
• Less than 5 GPS SVs - having some GLONASS SVs
  available will aid RTK initialization
• Positioning
• Less than 4 GPS SVs having some GLONASS SVs
  will aid positioning
• Improved VDOP
• Adding any GLONASS SVs will help to reduce VDOP

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Compass (Beidou)

• 4 geostationary (now in place) and 30 medium
  orbit (MEO) satellites for global coverage
• MEO launches starting early 2009
• Goal mid-2010 to have 10 SVs
• The Chinese Government has announced free 10
  meter accuracy access to all, however, the ICD
  has not been published.
• There is a high probability that Compass will
  become operational before Galileo

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Galileo EU GPS

• Milestones
• First SV launched 2005
• Operational target 2013
• Fee for service will compete with Free GPS
• Galileo will not be a factor in the Ag market for
  at least 3 or 4 years
• Expect to see lots of Galileo marketing
  activity for the next few years
• L1C to interoperate with GPS III SVs

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Questions?

• Art_Lange_at_Trimble.com
• Jorge_Heraud_at_Trimble.com
• WWW.Trimble.com