Aerospace and Defense Archives - Page 53 of 59 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

U.S. Air Force Plans to Improve GPS Constellation Geometry for Military Forces in Afghanistan

U.S. Air Force officials are moving to reconfigure the GPS constellation to create a 27-satellite geometry that will improve the availability and accuracy of positioning, navigation, and timing (PNT) capabilities for U.S. military forces in Afghanistan and Iraq.

Although the constellation currently has 30 operational space vehicles (SVs), not including the SVN49/PRN1 that has still not been set healthy, a number of the spacecraft are located nearby other satellites — effectively creating a 24-SV geometry. (See accompanying figure.)

By Inside GNSS

October 23, 2009

The Top Ten in PNT

Since the dawn of humanity, the sky and stars have stimulated our imagination and curiosity. As our understanding about outer space increases, so does our passion and drive to explore beyond the reaches of our own planet — and to use space to understand our own planet.

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GNSS Milestones

Rome wasn’t built in a day, and neither was the Global Positioning System.

Nor will the emerging GNSS system of systems arising from the regional and global infrastructures being put in place or modernized today: GPS, GLONASS, Galileo, Compass (Beidou-2), QZSS, GAGAN, IRNSS, EGNOS, WAAS, MSAS, and undoubtedly other acronyms yet to be born.

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September 19, 2009

Fireside GPS

My history with GPS began during the time of the “Cold War” in what was then Czechoslovakia. In 1975, the ION Journal of Navigation was the only information available to me. Despite that, my team at the Czech Technical University developed a GPS receiver and measured the position of our faculty in 1984. In those relatively isolated years, we gained a good deal of experience with GPS signals.

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Growing Up with GNSS

As I pack my bags for the damply enticing venue of Savannah, Georgia, I’m reminded that this is my 21st consecutive journey to an ION GNSS conference. And the number 21 still has a lingering resonance as the age of majority, the harbinger of having reached adulthood — if not maturity.

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September 17, 2009

OCX budget Cut Could Slow Program; First IIF Might Launch by May 2010

An increasingly likely $97.4-million cut in the GPS OCX budget for fiscal year 2010 (FY10) would slow down work on modernization of the operational control segment, but the Air Force would try to recoup any reduction in the FY11 budget.

Meanwhile, technical problems that have delayed development of the follow-on generation of Block IIF satellites are largely resolved and a first launch is expected in May 2010.

By Inside GNSS

July 31, 2009

GPS SVN49 Signal Anomaly: USAF Ponders Plan B

(Updated August 4, 2009)

A GPS community consensus is emerging that the initial proposal for mitigating the L1 signal anomaly causing elevation-dependent ranging errors on the SVN49 satellite isn’t the best approach.

By Inside GNSS

July 26, 2009

Satellite Numbers Game

The recent GAO report and Government Oversight subcommittee hearing on GPS sustainability generated more heat than light, with some major news media outlets leaving the impression that the sky (or at least GPS satellites) would soon be falling.

Perhaps the only silver lining in the ensuing Chicken Little phenomenon was the crude measure it provided of just how familiar (but not necessarily knowledgeable) private citizens have become with GPS.

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July 23, 2009

U.S. House of Representatives Trims $97 Million from OCX Budget, Cites Contract Delays

(Updated 11 a.m. (PDT), includes additional details from the GPS Wing)

A $97.4-million reduction in the GPS program made by the U.S. House of Representatives would affect the modernization program for the operational control segment (OCX), not the GPS III satellite budget as reported earlier.

In adopting the action of its appropriations committee, the full House approved H.R. 3326, the Department of Defense (DoD) Fiscal Year 2010 (FY10) budget, on July 30. The bill was referred to the Senate Appropriations Committee on August 3. In its report on the bill, the House committee said it made the cuts because of contract delays in the OCX program.

By Inside GNSS

July 21, 2009

ISRO Extends Raytheon Contract for GAGAN GPS Augmentation System

The Indian Space Research Organization (ISRO) has awarded a new $82 million contract to Raytheon Company to modernize the Indian air navigation system.

Raytheon will build the ground stations for the GPS-Aided Geosynchronous Augmented Navigation System (GAGAN), and the Indian Space Research Organization will provide the space segment and additional ground equipment. GAGAN will provide satellite-based navigation for civil aviation over Indian airspace and adjoining areas in south and east Asia.

By Inside GNSS

July 8, 2009

Pendulum’s Adds Options for GPS-12 Portable Frequency Standard Family

Pendulum Instruments, Stockholm, Sweden, has introduced four new options for the company’s GPS-12 Portable Frequency Standard family.

First released in 2006, the GPS-12R, a portable GPS controlled rubidium Frequency Standard with battery backup power, supplies a variety of standard frequencies for general metrology (1, 5, and 10 MHz), base station test (13 MHz) and telecom (E1/T1 clock/data).

By Inside GNSS

July 4, 2009

Making Sense of GPS Inter-Signal Corrections

The downloadable PDF (above) contains bonus material not available in the print edition. Appendices and other information on this subject is available at the bottom of the page.

The current version of the master GPS Interface Specification document (IS-GPS-200 Rev D March 2006) contains a new dual-frequency ionosphere correction algorithm that is to be used with the modernized GPS space vehicles (SVs) and their next-generation modernized GPS signals.

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June 16, 2009

ESA Signs Galileo IOV Launch, FOC Satellite Contracts

On June 15, the European Space Agency (ESA) signed contracts for launch services on the Galileo in-orbit validation (IOV) satellites as well as two additional contracts for “long lead items” needed to build the full operational capability (FOC) Galileo constellation of satellites.

The first contract, with Arianespace, will provide launch services for the four IOV Galileo satellites that will be placed in orbit by the end of 2010. Two Soyuz rockets, each carrying two Galileo spacecraft, will launch from Europe’s Spaceport in French Guiana.

By Inside GNSS

Aerospace and Defense

GNSS Hotspots | November 2009...

Obama Signs Bills Cutting Funds for eLoran, HIGPS, GPS OCX...

U.S. Air Force Plans to Improve GPS Constellation Geometry for Military Forces in Afghanistan

The Top Ten in PNT

GNSS Milestones

Fireside GPS

Growing Up with GNSS

OCX budget Cut Could Slow Program; First IIF Might Launch by May 2010

GPS SVN49 Signal Anomaly: USAF Ponders Plan B

Satellite Numbers Game

U.S. House of Representatives Trims $97 Million from OCX Budget, Cites Contract Delays

ISRO Extends Raytheon Contract for GAGAN GPS Augmentation System

Pendulum’s Adds Options for GPS-12 Portable Frequency Standard Family

Making Sense of GPS Inter-Signal Corrections

ESA Signs Galileo IOV Launch, FOC Satellite Contracts