Inside GNSS Media & Research

NOV-DEC 2017

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12 InsideGNSS N O V E M B E R / D E C E M B E R 2 0 1 7 www.insidegnss.com U sing multiple GNSS can signif- icantly enhance signal acquisi- tion, satellite visibility, spatial geometry and measurement redun- dancy," said Bernhard Richter, Leica Geosystems GNSS business director. "We have always been about multi- GNSS and multi-frequency. Our users are not asking what 'kind' of position we give them; they are saying 'Give us the best possible position', period." We spoke to Richter about his com- pany's habit of pushing technological boundaries in the service of its very real-world clients. "It was volatile technologies back in the 80s," he recalled, "back when it all started, when you had GPS and you had to work out how to track the L2P; that was a big job. And when you'd figured that out, here comes GLONASS, which wasn't a reliable system at that time— you couldn't fully rely on many things, the clocks, the orbits, etc. On top of that you had FDMA instead of CDMA and it was a hell of a job to solve all the biases." Understanding and incorporating GLONASS was not easy work, but it gave Leica Geosystems valuable experi- ence in how to combine different GNSS within a single functioning receiver sys- tem, to deliver better results than could be achieved with either system alone. Leica Geosystems, part of Hexagon along with NovAtel, has a long history as an industry leader in measurement technologies. Since 2009, the company has been exploiting multi-constellation and multi-frequency GNSS, including incorporating latest addition Galileo, to greatly improve the performance of high-precision real-time kinematic (RTK) positioning. Then Came Galileo "We brought GLONASS to market in 2006," Richter said. "After that, it was absolutely clear the next step was Galileo. The EU promised us a sys- tem, and there was a timeframe, so we wanted to be ready. We had prod- ucts on the market in 2009 that were Galileo-capable—E1, E5a, E5b and even Alt-BOC. We had the hardware. The only thing we didn't have was the E6. And most of our products that you've been buying since 2009 can be software upgraded for full Galileo-capability." For Richter and crew, it was a no-brainer. "We didn't even ask ourselves the question, 'Do we need Galileo or do we not need Galileo?'," he said. "It was always clear. Galileo helps you to deliver a better position, so if you want to play the high-precision game, you really have to support it." Everyone was on board, he said, at Leica Geoystems, at Hexagon, at NovAtel. One thing that surprises a lot of people, is that with comparable constellations, the Galileo-only positioning fares very well. "The thing is it's just more modern signals," he said; "So more signals, better multipath characteris- tics and all stronger than GPS L2 give you the better position at the end of the day. GPS is still considered the gold standard, for various reasons, but in terms of the Galileo signal structure, the code…the orbits are already very good, so when we look at a comparable situation—six Galileo satellites in view versus six GPS satellites in view—we have frequently a more precise posi- tion with Galileo." A powerful addition, then, to any- one's GNSS arsenal, but Galileo doesn't require a whole new skill set. "The Galileo project was really easy," Richter said. "We started in 2005, looking at the basic design of the first Galileo. From there, we pretty much understood our tasks and we finished on time. "It wasn't a finalized ICD (Interface Control Documents) but it's all clearly defined what they're doing, how the modulation looks, you know what to do. It really is a straightforward job, with fairly little risk around your investment decision. With GLONASS it was more or less the opposite." Richter also points out another key Galileo differentiator: "With multi-path mitigation, it has the best multi-path resistant output sig- Leica Geosystems bolstering its multi-GNSS arsenal BERNHARD RICHTER GNSS Opinion Leaders " The only thing we didn't have was the E6. And most of our products that you've been buying since 2009 can be software upgraded for full For Richter and crew, it was a no-brainer. "We didn't even ask ourselves the question, 'Do we need Galileo or do we not need Galileo?'," he said. "It was always clear. Galileo helps you to deliver a better position, so if you want to play the high-precision game, you really have to support it." Everyone was on board, he said, at Leica Geoystems, One thing that surprises a lot of people, is that with comparable constellations, the Galileo-only positioning fares very well. "The thing is it's just more modern signals," he said; "So more defined what they're doing, how the modulation looks, you know what to do. It really is a straightforward job, with fairly little risk around your investment decision. With GLONASS it was more or less the opposite." Richter also points out another key Galileo differentiator: "With multi-path mitigation, it has the best multi-path resistant output sig- The Leica GS18 T is described as the fastest and easiest-to-use GNSS smart antenna and RTK rover because users save time by no longer needing to hold the pole vertical to level the bubble. Photo courtesy of Leica Geosystems.

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