B: Applications Archives - Page 128 of 156 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

January 16, 2012

FIG /IAG Technical Seminar: Reference Frame in Practice

Monte Mario, the highest hill in Rome

A special seminar for geodesists will take place in Rome, Italy on May 4 and 5, just before the 35th FIG general assembly and working week.

The conference venue is the Cavalieri hotel on Monte Mario near the Vatican.

It is organized by the International Association of Geodesy (IAG), the surveyors’ international association (FIG) and the UN’s International Committee on GNSS (ICG).

By Inside GNSS

January 13, 2012

Optimal Aligning of the Sums of GNSS Navigation Signals

Working 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 Inside GNSS

Code Tracking and Pseudoranges

FIGURE 2: Pseudorange computation based on transmission. On the left side, the satellites are transmitting mes¬sages synchronously. On the right side, the four subframes are received asynchronously, due to the different propagation time. The TLM word is taken as a referene. The time differences ?i are computed on the basis of the relative arrival times of the front of the first bit of the TLM word.

Q: How can pseudorange measurements be generated from code tracking?

A: Every GNSS receiver processes the received signals to obtain an estimate of the propagation time of the signal from the satellites to the receiver. These propagation times are then expressed in meters to solve for the user position using trilateration.

By Inside GNSS

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New Austerity Squeezes GPS as DoD Tightens Its Belt

Embracing the need for debt-driven discipline, the White House has revised its strategy for the nation’s defense, taking a more fiscally constrained approach that reduces the number of troops and future spending on defense systems.

The new plan, formally announced January 5, was already being put into effect last summer. “The strategic guidance was the compass by which we steered the budget review leading to the president’s budget for fiscal year ‘13 and the years thereafter,” Deputy Secretary of Defense Ashton B. Carter told reporters.

By Dee Ann Divis

Winging It

FIGURE 1: Competitive group skydiving is currently judged by overlaying a grid on a photo and evaluating location of divers within its cells. Photo by Mark Harris.

»NovAtel Inc. wingsuit video

In 1589, at the age of 25, Galileo Galilei toiled up the 294 steps of a 55-meter bell tower in Pisa, Italy, where he was tutoring math students at the time.

According to his pupil and later biographer, Vincenzo Viviani, Galileo carried with him two cannonballs, one twice the weight of the other. When he reached the top of the tower, he went to the lower balcony of the tilted structure and dropped the two balls simultaneously.

By Inside GNSS

Raytheon Gets New Contract for GPS OCX Launch and Checkout System

In the latest in a series of GPS modernization contracts, the U.S. Air Force Space and Missile Systems Center has awarded Raytheon Company a $27.4 million contract to develop a GPS Launch and Checkout System (LCS), which will provide early launch and checkout of GPS III satellites starting with the first GPS III launch in 2014.

By Inside GNSS

January 12, 2012

USAF Awards Lockheed Additional GPS IIIA Satellite Buy

The U.S. Air Force has awarded Lockheed Martin a $238 million contract for production of the third and fourth satellites in the next-generation GPS constellation, known as GPS III. The acquisition of the next two GPS IIIA satellites at one time will allow the Lockheed Martin-led team to maximize efficiencies in satellite manufacturing.

By Inside GNSS

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January 11, 2012

Lockheed Gains GPS III Launch & Checkout Contract

GPS III satellite. Lockheed Martin illustration

The U.S. Air Force has awarded Lockheed Martin a $21.5-million contract to provide a launch and checkout capability (LCC) to command and control all GPS III satellites from launch through early on-orbit testing.

By Inside GNSS

December 27, 2011

China Publishes Compass /BeiDou “Test Version” of ICD; Key Data Missing

[Updated January 3, 2012] China released a long-awaited “test version” interface control document (ICD) for its Compass (BeiDou-2) GNSS system today (December 27, 2011). The 11-page publication covers its open B1 civil signal centered at 1561.098 MHz.

By Inside GNSS

December 26, 2011

Spirent Launches Data Sets of World City Environments to Aid GNSS Receiver Testing

Spirent Communications has launched of a subscription service for live GNSS (GPS, GLONASS, and QZSS) environmental-capture data set samples, recorded at major locations worldwide, in challenging urban and suburban conditions.

The data sets are designed for use with the company’s GSS6400 GNSS Record and Playback test System. They encompass a variety of recorded scenarios ranging from drive-through multi-level roads, tunnels, and car parks to drive-throughs in downtown areas with high-rise buildings.

By Inside GNSS

December 13, 2011

Lockheed Delivers GPS III Pathfinder Spacecraft

GPS III pathfinder satellite testbed. Lockheed Martin photo

The Lockheed Martin team developing the U.S. Air Force’s next-generation GPS satellites (GPS Block III) has delivered the program’s pathfinder spacecraft to the company’s Denver, Colorado–area facility.

The program remains on schedule for a 2014 launch of the first Block III space vehicle (SV).

By Inside GNSS

November 22, 2011

Figures 1, 2 & 3: Network RTK and Reference Station Configuration

Return to main article: “Network RTK and Reference Station Configuration”

By Inside GNSS

November 21, 2011

GNSS Hotspots | November 2011

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.