Global Navigation Satellite Systems Engineering, Policy, and Design
Equations 1 – 11Q: How does a GNSS receiver estimate velocity?
A: Stand-alone single-frequency GNSS receivers represent the largest slice of the commercial positioning market. Such receivers operate mainly in single point position (SPP) mode and estimate velocity either by differencing two consecutive positions (i.e., approximating the derivative of user position) or by using Doppler measurements related to user-satellite motion.
By Inside GNSS
Arlington, VirginiaNOAA’s National Geodetic Survey (NGS) Geospatial Summit will be held at the Crystal City Hilton in Arlington, Virginia on April 13-14, 2015.
Registration is now open. Early registration ends March 13, 2015.
NGS will be hosting three events, each one providing a venue for NGS to share information about its products and services as well as hear from its customers across the public and private sectors.
By Inside GNSS
Kauna’oa Bay and Beach, with Mauna Loa in the backgroundThe 2nd IEEE International Symposium on Inertial Sensors and Systems will be held at the Hapuna Beach Prince Hotel on the Big Island of Hawaii on March 23 – 26, 2015.
Online registration is open.
This event covers the latest developments in the area of modern inertial sensors and emerging applications.
Invited Speakers:
By Inside GNSS
The annual Space Weather Workshop will take place on April 13 – 17 2015 at the Millennium Hotel in Boulder, Colorado, U.S.A.
Registration will be open soon.
This meeting will bring together customers, forecasters, vendors, government agencies and researchers of space weather information.
By Inside GNSS
Lisbon CastleThe INSPIRE – Geospatial World Forum 2015 and industry exhibition will be held at the Lisbon Congress Center in Lisbon, Portugal on May 25 – 29, 2015.
The call for abstracts has closed. Early registration is open until March 10, 2015. Spot registration will be available.
This year’s theme is "CONVERGENCE: Policies + Practices + Processes via PPP" Plenary and thematic sessions include:
By Inside GNSS
Washington D.C. at sunsetThe eleventh annual GEOINT Symposium and exhibition will take place on June 22 – 25, 2015 at the Walter E. Washington Convention Center in Washington D.C., U.S.A.
Registration for the GEOINT Symposium will open in February 2015.
The event will feature keynote speakers, breakout sessions, and provide attendees an opportunity to learn from leading experts, share best practices, and uncover the latest developments from government, military and private-sector leaders.
By Inside GNSS
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. SLAVE TRADE
Bangkok, Thailand
These days getting the United States, Russia, China, and Europe to agree on a common policy seems to be an increasingly rare event.
That’s why the long-standing comity among system operators in the GNSS sphere is particularly notable and welcome. “Interoperable and compatible” is the first principle espoused by the four nations under the aegis of the International Committee on GNSS.
By Dee Ann Divis
A decade has passed since the first GNSS system-level authentication protocols were proposed, and yet the current ongoing discussion is still, “Do we really need GNSS signal authentication?” Indeed, the current argument is whether we need authentication at the system level (the satellite broadcast service) or whether user-based authentication (anti-spoofing) is sufficient for a number of application requirements.
By Inside GNSS
No reality show contestant ever neared the finish line without the producers serving up another challenge. And so it is for would-be multi-GNSS users in the United States.
After dodging budget cuts, thwarting other teams’ attempts to grab critical frequencies, and dealing with jamming and technical problems, members of the U.S. GNSS community were thrown another curve late last year when they learned that signals from GLONASS and other international constellations must be authorized for use in the United States.
By Dee Ann Divis
It is well known that carrier phase ambiguities are integer values. Intuitively, this is hard to understand with a common counter-argument progressing along these lines: even if the receiver measures the instantaneous phase of the incoming signal (thus removing any fractional cycle component at the receiver end), the phase of the signal at the satellite cannot be guaranteed to be zero, so how can the ambiguity be integer?
In this article we explain why the carrier phase ambiguities are indeed integer.
By Inside GNSS
Figure 1; Tables 1 & 2After some years of concept studies and simulations, the Galileo Commercial Service is taking off. The journey has started toward what can be the most accurate and secure worldwide satellite-based navigation services for civil use.
By Inside GNSS
