In late March, I conducted a webinar titled "A Closer Look at L5: The Future of High-Precision GNSS," in which I discussed the impact that the new GPS L5 signal/frequency may have on high-precision users. Then, in April I was part of a discussion panel-format webinar titled "LightSquared: Our Story So Far." Many questions and comments arose from both webinars, and I'll attempt to address those in this column. read more
In the past 20+ years, I’ve seen a lot of really fantastic GIS technology in many parts of the world. However, during my trip to the Denver, Colorado, area last week, I saw something that was truly mesmerizing. My concern is that I won’t be able to adequately describe it for you. Before the cool stuff, I want to briefly... read more
Interference, detection, and mitigation — these have become topics of paramount importance to the GNSS community recently, surpassing at times even those old familiar standards accuracy, availability, and integrity. In March, a large expert audience attended a GNSS Interference, Detection, and Mitigation (IDM) conference at the United Kingdom’s National Physical Laboratory near London. My conclusions first, followed by reportage of the details. read more
To illustrate the fix we’re in, Logan Scott offered this analogy for out-of-band interference during the April webinar, “LightSquared and GPS: Our Story So Far.” We’re driving at night and come upon a bicylist with one of those little flashing lights. That’s the GPS signal. So far, so safe. We know the bicyclist’s position. Then around the bend comes a truck with its headlights on high-beam, in the adjacent lane, but brights set at our eye level. That’s the LightSquared signal. Where’s the bicyclist? Uh oh. read more
Improving Single-Frequency RTK in the Urban EnviornmentA look at how Doppler measurements can be used to smooth noisy code-based pseudoranges to improve the precision of autonomous positioning as well as to improve the availability of single-frequency real-time kinematic positioning, especially in urban environments. read more
Plus: GLONASS CDMA Tracked, Third Beidou-2 Launched The second report from non‐governmental members of the LightSquared/GPS Technical Working Group (TWG) was filed with the Federal Communications Commission (FCC) on April 15. For those anxious to see actual results of interference/desensitization of GPS receivers by the proposed LightSquared terrestrial signal — or, conversely, absence of said results — the report does not contain... read more
The Fehmarnbelt Positioning System between Denmark and Germany includes a geodetic basis, four permanent GNSS stations, and a real-time kinematic (RTK) service for construction of a road and rail causeway between the islands of Fehmarn, Germany, and Lolland, Denmark across the Fehmarnbelt, a 20-kilometer stretch of open water in the Baltic Sea. This homogeneous, consistent, coherent, highly accurate GNSS-based positioning system exemplifies comparable systems and services that can be established for any major construction site or infrastructure project. Now in use for environmental, geotechnical, and geophysical investigations, it provides cost-efficient operations and facilitates the precise navigation of large, costly offshore equipment. read more
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