Expert Advice: The Strategic Significance of Compass

December 1, 2010By

On November 1, 2010, China’s state news agency reported that the sixth Compass satellite was launched from the Xichang Satellite Launch Center. This was the fourth Compass satellite put into orbit this year, following launches in January, June, and August. Joining the United States, Russia, and the European Union, China is deploying is own global navigation satellite system of five geosynchronous satellites, 27 in medium Earth orbit (MEO) and three in highly inclined geosynchronous orbits (IGSO). Sometimes referred to as Beidou-2, Compass is a global RNSS (radio-navigation satellite system) that broadcasts one-way precision time signals to enable receivers to calculate their position. An earlier Chinese satellite navigation system, Beidou-1, was an RDSS (radio-determination satellite system) that provided regional coverage and required two satellites to get a position fix using two-way communications with a centralized ground station. read more

This article is tagged with and posted in BeiDou/Compass, Expert Advice & Leadership Talks, GNSS, Opinions

The System: QZSS Puts L1C on the Air

December 1, 2010By

QZSS Puts L1C on the Air JAVAD Receivers Track the First Truly Interoperable Signal JAVAD GNSS engineers in Moscow have released plots of the C/A, L2C, L5, SAIF, and the new L1C signals broadcast by Japan’s QZSS Michibiki, the first satellite to transmit L1C. The company stated that all of its current GNSS receivers can track QZSS signals with a... read more

This article is tagged with , and posted in BeiDou/Compass, Galileo, GLONASS, GNSS, The System

GNSS RF Compatibility Assessment: Interference among GPS, Galileo, and Compass

December 1, 2010By

A comprehensive methodology combines spectral-separation and code-tracking spectral-sensitivity coefficients to analyze interference among GPS, Galileo, and Compass. The authors propose determining the minimum acceptable degradation of effective carrier-to-noise-density ratio, considering all receiver processing phases, and conclude that each GNSS can provide a sound basis for compatibility with other GNSSs with respect to the special receiver configuration. read more

This article is tagged with and posted in BeiDou/Compass, Galileo, GNSS, Signal Processing

The System: Galileo PRS Delivery in Question

November 1, 2010By

Once envisioned to orbit 30 satellites, Galileo’s constellation has over time been reduced to a planned, though still not space-borne, four initial satellites plus 14 operational satellites for a total of 18. The European Space Agency (ESA), under direction of the European Commission (EC), confirmed at the October 19–21 European Navigation Conference (ENC) in Germany that it plans to declare... read more

This article is tagged with and posted in BeiDou/Compass, Galileo, GNSS, The System

The System: Michibiki Takes Up Station and Other GNSS Constellation Updates

September 1, 2010By

As this issue goes to press in late August, the first Japan Aerospace Exploration Agency Quasi-Zenith Satellite System (QZSS) space vehicle, nicknamed Michibiki, holds steady for a September 11 launch. QZSS will use multiple satellites in inclined orbits, placed so that one satellite always appears near zenith above Japan, well known for its high-rise cities. The design provides high-accuracy satellite... read more

The System: Vistas from the Summit

April 1, 2010By

“This is an event where one gets one’s goals for the next year.” Paul Verhoef, program director for satellite navigation programs of the European Commission, may have exaggerated for effect, and for the benefit of his audience and hosts at the Munich Satellite Navigation Summit in March. But not by much. The conference, now in its eighth year, has assumed... read more