More Compass Points: Tracking China’s MEO Satellite on a Hardware Receiver
Launch of a Compass Satellite
On April 14 China launched its first medium-Earth-orbit (MEO) satellite code-named Compass-M1, the first in a planned constellation with global coverage based on the same principles as GPS and Galileo. In order to investigate the space vehicle’s characteristics and data structure, researchers modified a GPS/Galileo hardware receiver so as to track the Compass MEO satellite. This article tells how they did it and presents the first results of their efforts.
In 2000 China deployed the Beidou-1 navigation system. Originally this S-band system provided ranging information via geostationary satellites that operate as transponders. This system design required bulky two-way radios, had a limited capacity, and coverage was restricted to East Asia.
Currently, China is developing the successor to this system, called Beidou-2 or Compass. The Compass Navigation Satellite System (CNSS) will consist of 30 medium-Earth-orbit (MEO) satellites broadcasting code division multiple access (CDMA) signals in the L-band. Unlike the relatively large user equipment of Beidou-1, Compass will support global navigation by means of small handheld receivers.
This explains the burst of research activity after launch of the first Compass satellite (Compass-M1) in April this year, particularly because China didn’t disclose any details about its operation. In an article published in the May/June issue of Inside GNSS, researchers at CNES, the French space agency, presented dish-antenna measurements of the Compass-M1 signal and unveiled the main code properties. Subsequently, a Stanford University (SU) team undertook complementary measurements and worked out the spreading code parameters.
(For the rest of this story, please download the complete article using the PDF link.)
ManufacturersThe GeNeRx1 GPS/Galileo receiver used to track the Compass-M1 signals is manufactured by Septentrio N.V., Leuven, Belgium. The choke ring antenna is from Orban Microwave Products (OMP), Leuven, Belgium.
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