SURVEYING FOR AEC initial investment worthwhile. “We have big plans for our rovers,” said Brian Cortese, Engineering Tech/Inspector for the City of Ellensburg Public Works & Utilities. Ellensburg is a vibrant town that is attracting a lot of new development and it is being proactive in surveying and mapping assets as they are added or replaced. “We’re recording manholes and valves, sewer systems, storm water systems, irrigation, hydrants — everything that gets built in the city gets as-built surveyed,” Cortese said. “Precise, real-time positioning, it’s been a benefit to us already. We can go out before they work on the subgrade for new developments and take measurements, and then when they finish the subgrade and pave it, we can go back and locate those exact positions.” Ellensburg uses corrections from the statewide cooperative RTN. In fact, one of the RTN reference stations —also part of the NOAA National CORS Network — is right in the center of town atop the science building of Central Washington University. While the city does a wide variety of surveying and mapping, with the Flex and RTN corrections surveyors get the same centimeter-precision for everything they measure in the field. “We’ve done design projects with it,” Cortese said. “For instance, we recently took measurements in an area of downtown for a proposal by recording positions and elevations to develop a new park and entertainment area for the community. We are also marking Americans with Disabilities Act (ADA) ramps to meet federal specs out in the field — it’s been really handy for so many things.” Brian Cortese FULL CONFIGURATION. Brian Cortese works for the City of Ellensburg, where he uses the FLEX Extreme Bundle for multiple field applications. Survey-Grade Rover To serve the full range of precision needs, the Flex had to be designed as a survey-grade rover. It has a full-constellation GNSS and RTK engine: GPS, GLONASS, Galileo, BeiDou, and support for other regional constellations. With more satellites in view, it can perform in sky-view-challenged locations, such as around buildings and under tree canopy. “Ellensburg is on the Tree City, USA list; our streets are very well lined with a variety of trees, which is also where a lot of our utilities are and development is going on,” Cortese said. “We have been able to get good precisions in and around those trees. Actually, someone on our staff is taking an inventory of the trees with the Flex and loading the data directly into ArcGIS.” Even in the more rural areas of Grant County that enjoy a lot of open sky, Schilling said, some areas planned for mapping are along upper tributaries and in the hills with a lot of tree coverage. He said the Flex has performed well in those areas. Choices The Flex offers these options and combinations: ■ Flex Extreme. Full survey-grade rover that can use a variety of correction types. ■ Base-Rover RTK. Two Flex Extreme units connected via radio. ■ External RTN/RTK corrections via NTRIP. ■ Bad Elf RTK Service. Single-tap access to a nationwide RTK corrections service. ■ PPP service. Atlas PPP corrections via L-band geostationary satellites. ■ Flex Standard. Pay-as-you-go high-precision-enabled service using tokens. ■ Static Logging. Observation file logging for post-processing (supported by Flex Extreme). ■ Compatibility with multiple field-mapping software applications. While many modern GNSS rover systems support one or more options similar to those listed above, Bad Elf’s Flex supports all of them, making it capable of a wide variety of applications. 24 GPS WORLD WWW.GPSWORLD.COM | FEBRUARY 2023
GPS World February 2023: Page 24
