Magazine Section Archives - Page 17 of 66 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

Urban Localization and 3D Mapping Using GNSS Shadows

It is by now well known that GNSS-based localization in built-up urban environments can be extremely inaccurate. This is a fundamental problem that hardware enhancements cannot solve.

A GNSS receiver estimates 3D location and timing from pseudoranges from four or more satellites, assuming that these pseudoranges correspond to direct line-of-sight (LOS) paths from each satellite. In urban canyons, however, the signal from a satellite to the receiver suffers from multipath propagation and shadowing.

By Inside GNSS

GLONASS for Precise Navigation in Space

Figures and Tables

The current stage of GLONASS evolution is aimed at meeting future user requirements of which the most important is the improved accuracy of positioning.

During the implementation of the GLONASS Space Segment Modernization Program (2012–2015), the GLONASS team is facing the situation in which it is not feasible to launch new navigation satellites because the existing constellation is comprised of GLONASS-M satellites operating beyond their guaranteed design lifetime. Nine more GLONASS-M satellites are in ground storage.

By Inside GNSS

Single Antenna, Dual Use

A GNSS single-antenna system can be compared to a single-pixel camera. Electromagnetic waves traveling 20,000 kilometers from every overhead direction can reach us. Yet once at the antenna, this diverse set of information is collapsed into a single magnitude and phase value, then sent off to the receiver so that value can be extracted.

By Inside GNSS

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New Fiscal Year Begins with Unfinished GPS Business

Most folks look to a new year as an opportunity for fresh starts and new projects. For the GPS community, however, the October 1 start of the 2016 federal fiscal year (FY16) will likely be more about the hangover — that is, the issues that are hanging over into the next 12 months, unresolved.

At the top of that list of unfinished business are two system decisions: a go/no-go determination on whether the United States will build eLoran as the U.S. backup to GPS and deciding whether or not to choose a new contractor for the GPS III program.

By Dee Ann Divis

July 22, 2015

Figures 2 – 5: More Than We Ever Dreamed Possible

Return to Working Papers article: "More Than We Ever Dreamed Possible"

By Inside GNSS

Tables 1 – 5: More Than We Ever Dreamed Possible

Return to Working Papers article: "More Than We Ever Dreamed Possible"

By Inside GNSS

July 20, 2015

Premature Farewell to GPS

There is nothing wrong with provocative, even disruptive, speech or ideas. Turning the world upside down every now and then can shake loose useful innovation along with the shopping lists and pocket change.

But U.S. Secretary of Defense Ashton Carter’s recently revealed comments on GPS (see 360 Degrees article) seem more in the category of “Loose lips sink ships.”

By Inside GNSS

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GNSS Hotspots | July 2015

One of 12 magnetograms recorded at Greenwich Observatory during the Great Geomagnetic Storm of 1859

1996 soccer game in the Midwest, (Rick Dikeman image)

Nouméa ground station after the flood

A pencil and a coffee cup show the size of NASA’s teeny tiny PhoneSat

Bonus Hotspot: Naro Tartaruga AUV

Pacific lamprey spawning (photo by Jeremy Monroe, Fresh Waters Illustrated)

“Return of the Bucentaurn to the Molo on Ascension Day”, by (Giovanni Antonio Canal) Canaletto

The U.S. Naval Observatory Alternate Master Clock at 2nd Space Operations Squadron, Schriever AFB in Colorado. This photo was taken in January, 2006 during the addition of a leap second. The USNO master clocks control GPS timing. They are accurate to within one second every 20 million years (Satellites are so picky! Humans, on the other hand, just want to know if we’re too late for lunch) USAF photo by A1C Jason Ridder.

Detail of Compass/ BeiDou2 system diagram

Hotspot 6: Beluga A300 600ST

1. RUM DEAL
Moscow, Russia, and Havana, Cuba

By Inside GNSS

Can you list all the properties of the carrier-smoothing filter?

Q: Can you list all the properties of the carrier-smoothing filter?

A: Carrier-smoothing filters, also known as Hatch filters, are commonly used to reduce (“smooth”) the noise and multipath errors in pseudorange measurements by exploiting the high-precision relative distance information from carrier phase measurements. However, carrier-smoothing filters operate on more than just noise and multipath, and this article summarizes the response of such filters to all relevant inputs.

By Inside GNSS

Officials Delay First GNSS Authorization Request; Light-Squared Tries to Leverage Issue

The U.S. stance on satellite navigation has long supported international cooperation and a degree of interoperability. In 2010 the Obama administration even adopted a space policy that said foreign satnav services could be used “to augment and strengthen the resiliency of GPS.”

That was easier in the abstract, however, when the only fully functional GNSS was GPS. Now, with other GNSS services coming online, American officials want to think things through again.

By Dee Ann Divis

ESA and EC at Odds (Again) over Space Governance

At the European Economic and Social Committee’s Space & Society Conference, from left, Daniel Calleja Crespo, director general of European Commission’s DG Growth; EESC Space and Society Project Coordinator Edgardo Maria Iozia, and Giulio Bartolani di Montauto, European Space Agency’s Brussels office.

Reporting from Brussels last year, we explained that the then–brand new EU GNSS Regulation had effectively put to bed years of wrangling over who does what in Europe’s GNSS programs. But the issue reared its head again in Brussels recently, in a highly charged discussion hosted by the European Economic and Social Committee (EESC).

By Peter Gutierrez

Valérie Renaudin’s Compass Points

Renaudin’s children, Satine and Kylian (left); Irish dancing keeps Renaudin on her toes (right).

Return to main article: "Valérie Renaudin: Navigating a Life with GNSS"

COMPASS POINTS

Engineering specialties

Geomatics engineering, design of dynamic position estimation algorithms, GNSS and other sensors, including inertial MEMS, UWB Tx, hybridization filters for navigation, low-cost sensor error modeling and calibration, and magnetic field processing.

By Inside GNSS