TAG: John Lavrakas

Expert Advice: Managing GPS, Take Two

December 1, 2014By

By John Lavrakas, Advanced Research Corporation What a difference eight years can make! My September 2006 GPS World article “Managing the GPS Constellation for Today’s Needs” dealt with GPS performance issues many high-precision users then faced. Demanding applications of real-time precision positioning, such as precision agriculture and machine control, did not find enough satellites in view to support their needs. I... read more

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Expert Advice: BeiDou, How Things Have Changed

February 1, 2013By

Economically, the System Differs Significantly from Its GNSS Cousins John W. Lavrakas In May 2007, I authored an article in GPS World looking ten years into the future and envisioning how the GNSS field would operate at that then-distant time. Reviewing my assessments, I see that I was both accurate and wide of the mark with my predictions. The prediction... read more

GPS Transmitter Frequencies

January 16, 2007By

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 frequencies for the L1 and L2 signals shall be coherently derived from a common frequency source within the... read more

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