By Inder Jeet Gupta It is well known that the phase center of a GNSS antenna can vary with the satellite direction. This phase center movement leads to aspect dependent carrier phase and code phase biases in the satellite signal. For precise geo-location, one needs to characterize the antenna-induce...
Read More →Why are the two GPS Transmitter frequencies (1575.42 and 1227.6 MHz) coherently selected integer multiples of 10.23 MHz master clock? Question posted on CANSPACE on October 30, 2006, by Sivaraman Ranganathan. The document defining the GPS signal, IS-GPS-200, states that “The carrier frequencie...
Read More →Why are GLONASS satellites launched on Christmas Day? Question posted on CANSPACE on December 10, 2006, by Kerry Matthews The latest triple-satellite GLONASS launch occurred on December 25th at 23:18 Moscow Time. This launch is the sixth GLONASS December launch in a row. In fact, all 9 launches sinc...
Read More →Innovation: The International GNSS Service: Any Questions? (PDF) By Angelyn W. Moore Published: January 2007 GPS World In this month’s column, Angelyn Moore, the IGS Central Bureau’s deputy director, overviews the organization’s service, history, and future, demonstrating that the IGS is a mod...
Read More →Innovation: GNSS Radio: A System Analysis and Algorithm Development Research Tool for PCs (PDF) By J.K. Ray, S.M. Deshpande, R.A. Nayak, and M.E. Cannon Published: May 2006 GPS World In this month’s column, a team of researchers from India and Canada describe a GNSS radio and how they have used it...
Read More →Innovation: Satellite Navigation Evolution: The Software GNSS Receiver (PDF) By Glenn MacGougan, Peter Ludvig Normark, and Christian Stahlberg Published: January 2005 GPS World In this month’s Innovation, we look at a further evolution of the GNSS receiver which offers the promise of flexibility, ...
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By James R. Clynch, Andrrew A. Parker, Richard W. Adler, and Wilbur R. Vincent, Naval Postgraduate School; Paul McGill and George Badger, Monterey Bay Aquarium Research Institute “Mr. Holmes, they were the footprints of a giant hound!” Engineers-turned-sleuths in Moss Landing Harbor, Ca...
Read More →Innovation: Assisted GPS: A Low-Infrastructure Approach (PDF) By Jimmy LaMance, Javier DeSalas, and Jani Järvinen Published: March 2002 GPS World Have you ever tried to use a GPS receiver indoors? Chances are, unless you were on the top floor of a wood-frame house and using a receiver with ample a...
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