The System

The System: eLoran Operational on Eastern UK Coast

December 1, 2014By
Bridge of the Galatea, a GLA vessel that carries a eLoran receiver and conducted tests of the new system.

Back-up to Vulnerable GPS Signals Required for Busy Shipping Lanes The General Lighthouse Authorities (GLAs) of the UK and Ireland announced October 31 the initial operational capability of UK maritime eLoran. Seven differential reference stations now provide additional position, navigation, and timing (PNT) information via low-frequency pulses to ships fitted with eLoran receivers. The service will help ensure they can... read more

The System: Fregat Design Ambiguity Steered Galileo Wrong

November 1, 2014By

Cross-Installed Hydrazine, Helium Lines Froze Thrusters The root cause of the anomaly that sent two Galileo satellites into the wrong orbit on August 22 was a shortcoming in the system thermal analysis performed during stage design, and not an operator error during stage assembly, according to findings by an independent inquiry board. The independent inquiry board was created by Arianespace,... read more

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The System: One Step Back, Three Steps Forward

September 1, 2014By
Galileo-MASTER-2014-W

Galileo IOV Bird Mute; New Draft ICD; CS Proved; Late August Launch Orbiting in silence since an onboard power mishap on May 27, troubled E20 emitted cheeps from space on August 6, 7,  and 8, broadcasting on the L1 frequency. Nothing has been heard since.  Meanwhile, the European Commission (EC) published a new draft version of the Galileo Open Service... read more

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The System: GPS III, Always a New Horizon

July 30, 2014By

First, Lockheed Martin began investigating options for its GPS III payload supply line last year.  Then in June of this year, the U.S. Air Force opened a “sources sought”  initiative for a production-ready GPS space vehicle, equipped with an alternate payload, for consideration alongside the Lockheed Martin-built GPS III vehicle. Grumman and Boeing have responded to the U.S. Air Force... read more

The System: GLONASS in April, What Went Wrong

June 24, 2014By
Figure 1. Affected broadcast messages for each GLONASS satellite. Colors indicate the different orbit planes.

By Gerhard Beutler, Rolf Dach, Urs Hugentobler, Oliver Montenbruck, Georg Weber, and Elmar Brockmann What Happened: On April 1, 2014, at 21:15 UTC, all GLONASS satellites started to transmit wrong Broadcast Messages (BM) as previously reported by GPS World. The satellite positions derived from these BM were wrong by up to ± 200 kilometers in each of the three coordinates... read more

The System: Sixth GPS IIF Launched into Orbit

June 1, 2014By
Photo credit: United Launch Alliance.

A sixth GPS IIF satellite was launched aboard a United Launch Alliance Delta 4 rocket from Cape Canaveral at 8:08 p.m. EDT May 16. The satellite, designated GPS IIF-6 and built by Boeing, is one of the next-generation GPS satellites, incorporating improvements to provide greater accuracy, increased signals, and enhanced performance for users. According to Boeing, each GPS IIF satellite... read more

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GPS/GLONASS Dispute: CEO Clarifies Misunderstandings

May 23, 2014By
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“Use any opportunity to create friendship and peace,” urged Javad Ashjaee, president and CEO of JAVAD GNSS, in a May 23 conversation with journalists. He decried the recent controversy about monitoring stations on both U.S. and Russian soil, saying it was based in misinformation and misinterpretations, inflated by a political crisis in a completely different area. “This [GNSS] is a... read more

The System: GLONASS Fumbles Forward

May 1, 2014By
GLONASS PLOT from the Roscosmos GLONASS Information-Analytical Centre, showing the 12-hour outage, with full service eventually restored on April 2.

Two April Disruptions Furnish Fodder for Multi-GNSS Receivers and Alternative PNT In an unprecedented total disruption of a fully operational GNSS constellation, all satellites in the Russian GLONASS broadcast corrupt information for 11 hours, from just past midnight until noon Russian time (UTC+4) on April 2 (or 5 p.m. on April 1 to 4  a.m. April 2, U.S. Eastern time).... read more