C+S February 2021 Vol. 7 Issue 2 (web)

Since the introduction of civil GPS in the 1980s, the technol- ogy has had a huge impact on the surveying profession. The expansion of the global satellite system, which we now refer to as GNSS, along with ongoing technology developments, have made the GNSS rover one of the most valuable tools in Taking full advantage of the rapidly increasing number of satellites and multifrequency signals requires dynamic surveying technology. How to Truly Benefit from GNSS Modernization

a surveyor’s toolbox for its ability to quickly cover large areas while providing accurate real-time positioning. But tak- ing full advantage of these developments requires more than simply having a GPS or GNSS rover. While the number of global satellites continues to increase, along with the availability and usability of multifrequency GNSS signals, only those surveyors using rovers with a high channel count and sufficient signal acquisition speed and sensitivity are able to benefit from these improvements. “GNSS technology has advanced significantly in response to GNSS modernization,” says Bob Kilburn, surveying and engineering product and applications manager for Leica Geosystems in the U.S. and Canada. “Using a rover that is de- signed to adapt to the highly dynamic changes of GNSS can provide substantial gains in efficiency and productivity.” Today’s satellite constellation is global and includes GPS, Glonass, Galileo and BeiDou, as well as modernizations in the systems themselves. Even Small GNSS Upgrades Make a Big Difference

In a webinar that is now available on-demand, Kilburn walked through a test scenario that demonstrates the value of using a rover that can take advantage of L5 signal capabilities; adaptive, on-the-fly satellite selection; and real-time correction data in remote areas. The test evaluated the difference in performance between the Leica Viva GS14 GNSS smart antenna, introduced in 2012, and the Leica GS16 GNSS smart antenna, introduced in 2016. Where the GS14 was able to track four satellite constellations with 120 channels, the GS16 was “fu- ture-proof” with 550 channels and the intelligence to adapt to chang- ing conditions through self-learning and selecting the optimal signals to deliver the most accurate positions (a capability Leica Geosystems calls RTKplus). The GS16 was also the first Leica Geosystems rover to enable the ability to use the global SmartLink service, which provides corrections even in remote areas where no reference data is available. The test crew took the two sensors into a wooded area where they had previously done a traverse with manual total stations for control. They captured the same points with the GS14 and GS16 to get an idea of where they could get initialization and how each solution would work in the field. The crew captured the first few points in the morning when there were very few L5 signals. Although the initialization time with the GS16 was slightly faster, the overall performance of both rovers was similar. How- ever, when the crew returned in the afternoon when more L5 signals were available, the difference in performance between the two rovers was significant. The advanced capabilities of the GS16 enabled the crew

This image illustrates the number of satellites available in around 2006, when GPS was the primary system.

Today’s satellite constellation is global and includes GPS, Glonass, Galileo and BeiDou, as well as modernizations in the systems themselves.




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