Introduction To Real-Time Kinematic (Rtk) Surveying - ashtech Z-Xtreme System Manual

Introduction to
Real-Time Kinematic (RTK) Surveying
In the early days of surveying with GPS, data collection time on a point was measured
in hours, few was the appropriate adjective to describe the number of points estab-
lished in a day, and completion of a large project could take weeks. The results of a
days work was not known until days later when the data was finally processed at the
main office. The equipment required to perform this seemingly magical task filled the
back of a Chevy Blazer and came at a price tag of approximately $150,000 each.
And, by the way, two sets of equipment were needed.
Imagine the scepticism if a user of that system were told that some day, data collec-
tion times would be measured in seconds, hundreds would describe the number of
points established in a day, and large projects could be completed in hours. Results
would be known immediately, in real time. The equipment required to perform this
truly magical task would be carried by one person all day, and the price of the entire
system would be under $40,000 (including both sets of equipment).
What you've just read is the difference between GPS surveying in the early 1980s and
GPS surveying today. Early GPS surveying was static in nature. A user sat on a point
for an extended period of time, 1-3 hours or more. If time permitted, this user would
move to another point after collection was completed. Data was then sent off to the
main office for post-processing. Only after the data was processed were the results of
the survey obtained. Since then, GPS surveying has become more dynamic in
nature. Equipment has become small enough to be portable. With the incorporation
of a radio link between sets of GPS equipment, data can be processed in real-time, as
it is being collected. New techniques in data processing has resulted in the ability to
establish precise positions in seconds. These advances allow for a user to move
around a project site, quickly establishing the position of objects of interest and seeing
immediately the fruits of his/her labor. This is RTK Surveying.
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