Global Navigation Satellite Systems Engineering, Policy, and Design
Though the United States has been working on a backup for GPS for years, and was actually close to completing an equipment update to that end in 2009, Europe may be the first to put in place a fully independent alternative for positioning and timing data — an economic insurance policy against satellite navigation signals being jammed or disrupted.
By Dee Ann DivisLooking over the initial budget of the Trump administration, we can safely say that the president and his timorous collaborators on Capitol Hill have a maximalist concept of providing for “the common defense” and a minimalist one for promoting “the general welfare,” two of the six missions enshrined in the preamble of the U.S. Constitution.
By Inside GNSS
Q: Would you prefer to have more signals or more satellites?
A: This is somewhat of a classic GNSS question, but before getting to the answer, let’s seek some clarity about what is being asked. First, by definition, “more” signals or “more” systems must be referenced against some baseline configuration. This is commonly assumed to be a GPS L1 C/A solution, and this assumption is also used herein.
By Inside GNSS
Speakers at the 9th Annual Conference on European Space Policy wasted no time in addressing the somewhat worrying failure of several Galileo onboard clocks, as revealed by European Space Agency Director General Johan-Dietrich Woerner at a press briefing earlier in January in Paris. He made clear at the time that the clock failures, while indeed troubling, had had no effect on the operational integrity of the Galileo system.
By Peter Gutierrez
Figures and ChartsThe GPS community and Virginia-based Ligado are weighing new and upcoming test results as the standoff over interference with satellite navigation services enters its seventh year.
The dispute centers on the company’s now modified proposal to build a terrestrial wireless network supported by frequencies originally allocated for satellites. Though there had been a move some years earlier to augment the satellite services with ground stations the company’s first plan envisioned some 30,000 high-powered ground terminals.
By Dee Ann Divis
EquationsWorking Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.
By Günter W. Hein
The Federal Communications Commission is being asked to choose between the immediate benefits of officially improving U.S. satellite navigation receivers and the possibility that, in doing so, it may raise interference levels in a neighboring band or make it harder to develop alternative uses for those adjacent frequencies.
By Dee Ann DivisAs with the notion of “disruption,” unpredictability can be useful. A move in chess or go, for instance. Or in the case of cuisine — say, when usurping Taco Thursday with chicken tagine. Even in negotiations, an unanticipated gambit can change the outcome positively.
Sometimes, of course, unpredictability is in the immanent nature of things. Despite advances in meteorological technology and science, weather continues to prove fickle. Foreknowledge of earthquakes remains difficult to pin down in space and time.
By Inside GNSS
The BeiDou Navigation Satellite System (BDS) is China’s contribution to the world in the domain of Global Satellite Navigation System (GNSS). The BDS is being developed by the Chinese government, mainly through military departments, with key considerations for China’s national security, economic interests and social progress.
By Ingo Baumann
Q: Is it possible to build a low-cost system to detect and locate a single GNSS jammer in near-real time?
A: GNSS jammers are an ongoing threat to the reliable use of GNSS. The problem of geolocating GNSS jammers can be addressed using a time-difference-of-arrival (TDOA) processing technique; however, this problem is quite different than geolocating jammers in other radio frequency systems. The two main differences are:
(1) No GNSS are available to use as a timing reference.
By Inside GNSS
Washington has seen a lot of transitions, so even amidst political controversy it’s generally business as usual.
For the GPS community that business, at least in the near term, will likely center on changes in federal leadership — with many key appointments, like a new Secretary of the Air Force, still to be determined. In addition — even at this early stage when new lawmakers are still trying to find their offices — there are issues and opportunities worth watching in emerging legislation.
By Dee Ann Divis
Equations
EquationsWorking Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.
By Günter W. Hein
