MARCH 2017 ANTARCTIC OASIS Thought Leader Product Review Economics Part 2 Death of the PLSS? JAVAD GNSS J-Tip Payroll and Revenue An Oasis in Antarctica » ERIK DAHLBERG Displayed with permission • The American Surveyor • March 2017 • Copyright 2017 Cheves Media • www.Amerisurv.com Adapting GNSS methods to scientific needs t first glance, the research station located in James Ross phrase “Antarctic Island’s unique post-glacial environment. oasis” seems to be The scientific program at Mendel is an oxymoron. But an ongoing effort supervised by the MU that’s how polar Faculty of Science. The Czech Republic Aresearchers refer to the north end of has been involved in polar research for James Ross Island. The largest island roughly three decades. Scientists from in the James Ross archipelago at the MU have conducted studies in the extreme northern tip of the Antarctic Antarctic since 1994, including multina- Peninsula, James Ross Island is shielded tional research programs and expeditions. from storms by the Trinity Mountains. A major part of the research at While glaciers cover 80 percent of its Mendel focuses on glaciology and land area, the island has large regions permafrost. The work also includes that are free of year-round ice. Until earth sciences of geology, geomorphol- it collapsed in 1995, a large ice shelf ogy, geochemistry, climatology and connected the island to the peninsula hydrology; biological disciplines such mainland. The exposed rock and tundra as botany, ecology, microbiology and provide important opportunities for soil biology; and paleontology. Yes, research and scientific activities. dinosaurs. Scientists have uncovered One of the newest scientific facilities dinosaur fossils in two separate geologi- is the Johan Gregor Mendel Research cal formations on James Ross Island. Station located on the Ulu Peninsula at In late 2015, a team of 11 MU scientists the far north end of the island. Named conducted the 10th expedition to the after the Czech scientist known as the station. They would continue the work of father of modern genetics, it is the Czech observation and data collection and follow Republic’s first permanent Antarctic up on the activities of earlier visitors. research facility. The station formally opened in 2007 after several years of Positioning at the planning and construction. Commonly Antarctic Circle referred to as the Mendel Polar Station, Like many scientific efforts, position the facility is owned by Masaryk information is an essential part of David Jindra collects GNSS data near the University (MU) in Brno. The station, routine data collection. Researchers Mendel Polar Station. Scientists use GNSS to which is built on permafrost, is the only need to map the location of specimens support a variety of research projects at the Czech facility in Antarctica. Displayed with permission • The American Surveyor • March 2017 • Copyright 2017 Cheves Media • www.Amerisurv.com A group of penguins “supervise” David Jindra and a group of Jindra as he collects GNSS observations. curious penguins on a beach at James Ross Island. and samples to correlate the data and to For research in this enable them to return to the exact same “ location for future work. And investigations region, accuracy of to characterize the behavior of the island’s glacier surfaces require the ability to make a few centimeters is accurate position measurements over time. However, the time and resources generally sufficient. available for accurate positioning are ” limited. Working under tight budgets, the researchers at the Mendel Polar Station generally sufficient,” Jindra said. “The effort must share duties that extend beyond their and time to achieve millimeter precision scientific roles. Necessary tasks such as could not be justified. The scientists have cooking, cleaning and maintenance occupy other things to worry about.” a significant portion of the time. Therefore, The need for small, simple equipment the processes to capture positions must be led the Czech researchers to select Trimble® simple, efficient and combine readily with GeoExplorer® series GNSS handhelds for the scientific activities. the project. In addition to convenient size According to David Jindra, a GNSS and and low power consumption, the onboard positioning expert and Trimble Geospatial Trimble Terrasync software was well-suited processing for geospatial data including distribution partner who accompanied the for the attribute-intensive data collection GNSS, total stations, digital levels as well 2016 expedition, the sparse geodetic control work. The handhelds could provide the as image management and processing for and lack of any real-time GNSS network durability and easy workflows needed terrestrial and aerial photogrammetry. near the station further hampered the for the work and Jindra’s methodology The software also produces a variety of positioning efforts. As he spent time with would increase productivity and accuracy. deliverables for use in GIS, CAD and other the researchers and began to understand For data processing, the team would use downstream systems. Pathfinder Office is their workflows and requirements for Trimble Business Center (TBC) and Trimble focused on GNSS post processing primarily accuracy, Jindra developed a strategy that GPS Pathfinder® Office software. Developed for mapping and GIS applications. would streamline the work. “For research in to support surveying and engineering One of the first tasks was to establish this region, accuracy of a few centimeters is applications, TBC provides analysis and suitable control at the Mendel Polar Station. Displayed with permission • The American Surveyor • March 2017 • Copyright 2017 Cheves Media • www.Amerisurv.com A GNSS handheld on a tripod serves as a reference station for positioning at the Mendel Station. A mark on the boulder provides a stable reference point. The nearest precise control point was at the the Chilean station to point 4003. Jindra positioning into their daily activities. With Chilean General Bernardo O´Higgins station compared the long-duration observations the Geo7X collecting data at the reference on the Antarctic Peninsula more than 50 with measurements taken during past cam- station, scientists carried Trimble GeoXH™ km (30 mi) away. Using a Trimble Geo7X paigns and confirmed that 4003 was indeed 6000 series GNSS handhelds to more GNSS handheld mounted on a tripod, Jindra stable. The dual-frequency, carrier-phase remote locations, ranging up to 15 km (9 mi) created a new reference point named “4003.” results reinforced the plans to use 4003 as from the base. All of their GNSS data could After collecting dual-frequency data over a reference station for the 2016 campaign. It be processed against the data from 4003. several days, Jindra downloaded the data will also provide a reference point for use by Because the baselines were in 15-km range, from the Geo7X and acquired corresponding future expeditions. they produced better accuracy than earlier data from the Chilean station. He then used When the local control was in place, expeditions that tied points to the distant TBC software to compute the baseline from the researchers could incorporate GNSS O´Higgins station. In addition to the shorter Displayed with permission • The American Surveyor • March 2017 • Copyright 2017 Cheves Media • www.Amerisurv.com year (6.5 to 10 ft), position accuracy of a few centimeters is sufficient. Following a process that is repeated every year, the team measured several hundred points on the glaciers to quantify changes in position at the bamboo rods. Data from the recurring measurement of coordinates is combined with remote sensing and climatology data to develop information about the glaciers’ evolution, motion, trends and shrinking volume. While more complex data analyses are conducted after the Tight quarters at Mendel Station combined sleeping areas and expeditions return home, they rely heavily workspaces. Team members on accurate GNSS data. Jindra said because shared common tasks of cooking, the teams could work quickly and confirm cleaning and station maintenance. each day’s data, the researchers came away with a high level of confidence in their results. They could also use TBC and lines, the ability to collect dual-frequency produce accurate positions at the bamboo Pathfinder Office to produce output and data reduced the time needed for GNSS rods with just three minutes of occupation reports formatted for use by other software observation at each location. time. Each day’s data was processed and analysis tools. in Pathfinder Office to produce 3D Because permafrost represents a Science in the Antarctic coordinates. “As you would expect, working continuously fluctuating material, another One of the most important uses of GNSS at on the glaciers was a good environment goal of the research was to better understand the Mendel Polar Station is for monitoring for GNSS,” Jindra said. “There are no the behavior and evolution of the ground at glaciers. Scientists are studying four glaciers obstructions and the satellite availability the station. For their studies on permafrost, on the island within 15 km of the station. was always quite good.” Because the glacial the team used GNSS approaches similar to On three glaciers, networks of bamboo rods motion could be on the order of 2-3 m per the glacier measurements. They identified are installed into the ice at regular intervals. Researchers use GNSS to measure the 3D position at the base of each rod. They also measured the distance from the top of the bamboo to the ice surface. To streamline the GNSS portion of the work, Jindra trained the scientists to use the stop-and-go kinematic method (SGK). The SGK approach is used to obtain precision similar to RTK but without the need to have a base station or other source of real-time corrections. The GNSS receiver collects satellite data continuously while in motion between points of interest. It is held stationary at a point for a few minutes. The in-motion and stationary data is down- loaded to post-processing software, which can then produce centimeter results.