Using GPS Laser Offsets

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Using GPS Laser Offsets
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The Basics of GPS Technology
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Global Positioning System (GPS)
Space Segment
your location is 37 23.323 N 122 02.162 W
Control Segment
User Segment
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Errors in GPS

• Obstruction
• Multipath
• Atmospheric conditions
• Clock bias
• Receiver hardware
• User

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Multipath Obstruction
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Minimizing Errors

• Post-process your GPS data
• Wait for good satellite coverage
• Use an offset!

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Maximize Productivity

• Use antenna on a range pole
• Maintain GPS lock between features
• Maintain view on 5 or more satellites
• Dont expect best results in harsh environments
• Use an offset!

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Other reasons for an Offset

• You cant get there (private property or behind a
  locked gate)
• You dont want to go there (its not safe)
• You can be more productive from one spot (map
  multiple features)

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MAP THIS.
STAND HERE.
MAP THIS.
STAND HERE.
MAP THIS.
STAND HERE.
MAP THIS.
STAND HERE.
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Measurement Values 101 The basics
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Software Integration
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About Compass Technology Helpful Field Tips
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Compass Sensing
FACT Local magnetic interference will cause
accuracy breakdowns regardless of what compass
you use.
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Be Aware of Proper Magnetic Hygiene
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The MILLION DOLLAR Question
NO!
Can you use a compass from inside your vehicle?
YES!
Can you still perform laser offsets from your
vehicle?
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Compass Calibration
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Simple Field Test to Determine Magnetic
Interference
Target / Step Test 1.) Choose a target, shoot
it and note the azimuth. 2.) Step along the
sight line and shoot the same target again.
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Summary Why Offset?

• Poor GPS coverage
• Inaccessible target
• Unsafe to reach
• Increase efficiency

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Questions?
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Contact Information

• Jay Riester
• Mapping Tech Support
• jriester_at_seilerinst.com
• http//solutions.seilerinst.com
• http//seilermapsupport.wordpress.com/