For decades, equipment operators took their instructions from stakes
in the ground that had to be moved and reset as the work unfolded. Grade
stakes will soon be obsolete, thanks to 28 Global Positioning Satellites
that send radio signals to earth. Onboard GPS receivers allow scrapers,
dozers, and graders to plot accurate courses with little or no reference
to in-ground markers.
McAninch adopted GPS in 1999 when Trimble Navigation introduced the
dual-antenna Site Vision system that employs guidance and machine control.
Light bars mounted in the operator’s field of vision signal proper
blade angle as the machine moves, while a video display shows the proper
cut or fill on the job site. The immediate benefits are speed and extreme
accuracy.
With GPS, supervisors no longer have to reset stakes, so they can
concentrate on haul routes and cycle times. At day’s end they
drive their sites in GPS-equipped pickups and send progress data to
the home office so estimators can check productivity against the original
schedule. All earthmoving tasks and management functions are improved
by GPS.