With the advances of RTK, are the days of post processing
coming to an end? According to surveyors in the field,
e’ve heard the stories from the early days of
GPS: Surveyors endured long days of fieldwork
followed by longer nights of downloads and
processing, only to discover the need to redo a day’s work.
Frustrating? Very. The payoff came with massive increases
in productivity and precision compared to the optical
methods of the day. But in order to reap the benefits
of GPS, data processing was a necessary—sometimes
painful—fact of life. The industry was ripe for change,
and surveyors eagerly embraced the arrival of real-time
kinematic (RTK) methods, which led many to predict a
rapid end for post processing. But in spite of widespread
use of real-time techniques, post processing continues to
play an important role in GNSS surveying.
The key lies in choosing the appropriate technique, and in
understanding how post processing contributes to pro-
ductivity in both field and office. When setting up large
or long-term projects, it’s common to establish a refer-
ence frame for positioning. Surveyors place points where
needed to supply control for subsequent surveying using
both RTK and optical approaches. These local networks
are often built using short, internal baselines combined with
ties to more distant control points. This provides internally
consistent control across the project. Static GNSS with
post processing provides robust results and high con-
fidence and is the usual tool of choice for this work.
Even in small or shorter-term projects, post processing
delivers important benefits in precision and accurate
Tools for the Job
With the decision to use post processing in place, sur-
veyors develop their strategy for data processing. The
options include processing data in-house or accessing an
online service such as the U.S. National Geodetic Survey
(NGS) Online Positioning User Service (OPUS) system or
the Trimble CenterPoint™ RTX™ Post-Processing Service.
Each option has important benefits.
Utilities surveyor collects data using RTK. RTK inFill and post processing
provides the highest flexibility in the field.
A Trimble R7 GNSS collects static data for for post processing. The Trimble
Zephyr™ GNSS geodetic antenna helps mitigate multipath.