Global Navigation Satellite Systems Engineering, Policy, and Design
The navigation sensors for location-based services (LBS) are complex technical systems. Modern technical science can answer most questions about the optimality of particular position determination methods, signal processing algorithms, electronic circuits or similar well-defined problems, but the rigorous answer to the questions concerning the optimal LBS positioning sensor are still a big problem.
By Inside GNSSAmerican Election 2016 — now that was something, wasn’t it?
A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.
Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?
So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?
Well, the tea leaves are a little unclear.
By Dee Ann Divis
With the Republican Party now entirely in charge of Washington’s prime policy real estate the neighborhood is going to change. The current residents are warily watching the newcomers take measurements for a major remodel of agencies, lobbying rules, national priorities, and international relationships, and everyone is assessing the implications of the new landscape.
By Dee Ann Divis
GNSS & The Law delves into the debates and developments around the new area of global satellite navigation system law.
This occasional feature by guest writers is coordinated by Ingo Baumann, co-founder and partner of BHO Legal in Cologne, Germany. His practice focuses on European high technology projects mainly in the space sector.
By Ingo Baumann
GPS seems to have come out of nowhere. There was no progression like eight-track tape to cassette to CD to MP3 player. One day we were driving around clueless of where we were, struggling with roadmaps bought as gas stations that couldn’t be folded back neatly once opened and — suddenly — there was an amiable female voice coming out of the dashboard offering directions to our destination and showing no signs of impatience when we made wrong turns.
From the author’s introduction to GPS for Everyone
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
Q: What are the challenges of ray-tracing for GNSS applications?
A: Simulating the propagation and reception of GNSS signals in complex environments is a challenging task. Indeed, the user always has to trade off between the computation time and the reliability of the output. Moreover, the motion of GNSS satellites, atmospheric effects, and building geometry are always difficult to model.
By Inside GNSS
This year India entered the club of nations operating their own satellite navigation system. The Indian Regional Navigation Satellite System (IRNSS) has a constellation of seven satellites – three in geostationary orbit and four in geosynchronous orbit — that are currently functioning satisfactorily from their designated orbital positions.
By Ingo Baumann
EquationsThe advent of multiple constellations provides the opportunity to eliminate geometry weakness as a source of satellite-based augmentation system (SBAS) unavailability. GPS users occasionally encounter areas where an insufficient density of satellites exists to support all desired operations. This most often occurs when a primary slot satellite is out of service. However, adding one or more constellations easily compensates for this geometric shortcoming. In fact, we may now experience the opposite problem of having more satellites that can be tracked by a receiver.
By Inside GNSS
Figures 1 & 2Spacecraft in low Earth orbit (LEO), at altitudes below 3,000 kilometers, remain within the main Global Positioning System (GPS) signals’ Earth coverage. Spacecraft employing GPS at these altitudes enjoy signal availability and navigation and timing performance emulating that of terrestrial users.
By Inside GNSS
Combined GPS + Galileo constellation. Image source: Nottingham Scientific Ltd., UKExperts working on standards for airborne equipment using GPS, Galileo, and a satellite-based augmentation system (SBAS) appear to have found a way to deal with an unusual problem — too many satellites.
By Dee Ann Divis
Park rangers in Death Valley National Park have begun calling it “death by GPS.” Visitors faithfully following their navigation devices turn down the wrong road or hike away from help and die before rangers can reach them.
But it really isn’t the GPS, it’s the maps in their navigation system’s database.
By Dee Ann DivisHow do you win when you are really losing?
Play a different game, move the goalposts, change the rules.
For several years now, a series of would-be wireless broadband service providers have been attempting to convince the Federal Communications Commission (FCC) to repurpose radio frequency spectrum near the GPS L1 band.
Past efforts have failed because of the transmissions’ demonstrated harmful effects on GPS and other GNSS signals. Now a new contender is trying to gain FCC’s approval by changing the way that those effects are measured.
By Inside GNSS
