Geotechnical News • September 2017
27
GEOTECHNICAL INSTRUMENTATION NEWS
This coincides with the horizontal
movement measured by a nearby
inclinometer during the same
period.
• There is a clear daily cyclical pat-
tern shown in the monitoring data.
This is related to the residual of
atmospheric errors after the major-
ity of them have been removed
by differential positioning. Thus
applying a 24-hour averaging on
the detailed one-minute interval
data would further improve the
precision of the results.
• There are a few major spikes
shown in the data, which is due to
the rainy weather as recorded by a
local weather station.
Final words
The pilot project demonstrates that
with today’s developments in GNSS
hardware and post-processing tech-
niques, a GNSS system specially
designed for geotechnical I&M pur-
poses is capable of achieving millime-
ter-scale precision at acceptable cost
and low power needs.
As more GNSS systems become
globally operational by the end of
this decade, the availability of GNSS
satellites will be largely increased
while the hardware cost will decrease.
Using GNSS for high precision, near-
real time monitoring is anticipated to
become common in supplementing
the existing conventional geotechnical
I&M methods.
Zhangwei Ning
Sixense
11812 North Creek Parkway N,
Suite 104B, Bothell WA 98011
Tel: (206) 588-1691
Email: zhangwei.ning@sixense-
group.com
Marc Fish
WSDOT Geotechnical Office
1655 S. 2
nd
Ave, Tumwater WA
98512
Tel: (360) 709-5498
Email:
