Equipment Setup
• Current OS and GPS Firmware installed.
• Current Date and Time on the data collector.
• Data collector is fully charged.
• Turn off WiFi and Bluetooth to conserve battery.
• Automobile charger and serial clip for charging.
• Factory reset the unit during a off/slow period.
Logging Settings in TS 3.3
• 1 second interval is default.• Auto Pause Count for point/vertex.• Horizontal/Vertical and In the Field/Post
Processed accuracy settings.• Post Processing Distance from Base.• Accuracy based logging.• Estimated Accuracy icon on the status bar (click
on it to display).
Multipath
• Occasionally multipath errors still occur.• Estimated error doesn’t always include multipath.• Zephyr has better multipath rejection (Stealth technology).
Best Practices: In the field
Minimizing multipath:– Multipath is like TV ghosting, caused by reflected
signals adding errors to the distance measured to the satellite.
Best Practices: In the field
Collect good GPS measurements between features
• Treat the measurements before and after the feature as if they are just as important as those logged at the feature itself – because they are!
• Keep the GeoExplorer unit “high”.
• Face antenna to the Southern Sky when using unit without external antenna.
• Hold the antenna horizontal while walking.
• Don’t drop the antenna to your side (or it will pick up multipath).
Best Practices: In the field (cont’)
Collect positions for at least 30 seconds at each point feature:– In theory, you don’t have to collect too many positions
in a point feature, once the accuracy indicator readings are good enough.
– But if you collect for about 30 seconds, you increase the chance of acquiring more satellites or cancelling out short-term multipath errors.
– If the accuracy indicator readings are poor, you should log more positions.
– This will typically be necessary in a hostile GPS environment.
Best Practices: In the field (con’t)
Antenna position– Can you really hold
the antenna still directly over the target?
– Use a pole, bracket, and plum line or bubble.
Log Now or Later
• Log Now – start a feature and simultaneously start collecting GPS position.
• Log Later – start a feature, enter attributes and start collecting GPS positions later. Use this for
lines and areas too. Also best for points if not using an external antenna.
Best Practices: In the field
Pause logging before entering attribute information:
– Allows you to concentrate on positioning:• Holding the antenna over the location to be
measured.• Holding the antenna horizontal with a good view of
the sky.
– It is not easy to do this while concentrating on entering attribute information.
Best Practices: In the field
– Avoid blocking satellites with your own body by using an external antenna and pole.
– Monitor your “In The Field Accuracy”.– The majority of satellites are between you
and the equator.
Denver, USA Frankfurt, Germany Christchurch, New Zealand
Planning skyplot View future satellite
constellation, including trajectories and trails.
Use time in the field more efficiently
Increase productivity
In Field Planning
Best Practices: In the field
Buildings or other obstructions– Wait for stable carrier lock. – Avoid blocking satellites.– In difficult locations, move the antenna slowly.– Use the Planning software to see if better DOP will be
available later.– Use offset measurements or Laser Rangefinder.
Under trees: Not always subfootDepends on: • Number of satellites tracking carrier (5 plus).• Carrier lock duration (2 minutes).• Distance to base station (50 miles).
Best Practices: In the field
Trees and canopy
– Use an external antenna on a pole.
– Wait for a stable lock before entering canopy environments.
– Use the Planning software to see if better DOP will be available later.
– Use offset measurements or Laser Rangefinder.
Light Canopy
Heavy Canopy