The U.S. Goverment's Global Positioning System, or
GPS, provides accurate location and time information virtually
anywhere in the world to anyone with a receiver. GPS satellites
orbiting the earth send signals that can be picked up and used by GPS
receivers. Software in the receiver translates the data into a
particular "three-dimensional" location (plus the precise time.)
For most people that means they can purchase a
portable navigational aid, or possibly have one installed more
permanently in their vehicle. Commercial vendors add software features
such as point-to-point map displays showing a good route to take
advantage of this data, but
there are many other applications as well in aviation, agriculture,
public safety, military, and naturally, surveying and mapping.
Surveyors require a different sort of equipment,
of course. People are
very concerned with the boundaries of their property, and
so "survey-grade" GPS-enabled equipment relies on multiple
receivers to
further improve accuracy, reliability, and precision well beyond what's
necessary to help a driver locate a street address.
Using GPS-capable survey equipment it's possible
for one or two surveyors to efficiently accomplish in days what might
have taken weeks with an entire team using older techniques and tools.
GPS
surveying is unaffected by weather or lighting, and is not constrained
to line-of-sight visibility between reference stations (unfortunately,
the satellite signals can be blocked by forest canopy, so more
traditional tools and techniques are still necessary in certain
settings.) Older methods were prone to errors, particularly when one
survey built off the work of another - now precise positional data
paired with special recievers and protocols for surveying has improved
the accuracy of surveys and mapmaking dramatically.
We use several different GPS enhanced tools that
take advantage of the highly accurate data to provide you with quick,
precise, reliable surveys and maps. If you want a more
detailed explanation of the satellites and signals, and other ways
they're being used, visit: www.gps.gov