NavList:

I wish I’d read Frank’s explanation before pondering my own, which effectively comes to the same conclusion.  It’s probably the ‘firmware’.  GNSS receivers find their position by calculating the intersection of range spheres emanating from the satellites.  The don’t use elevation and azimuth.  These are ‘back-calculated, if you like, from the receiver’s position and the satellite’s ephemeris primarily for the benefit of researchers seeking explanation of anomalies in the quality of satellite ranges.  E.g., the satellite might be low on the horizon, or temporarily be hidden behind a building.  The receiver might be in the ideal position to temporarily receive signals bounced off a building in addition to the direct signals.  For most of us, such additional information is more for entertainment than strictly necessary.   Even researchers probably don’t need super accuracy in azimuth and elevation.  If they do, they’ll be using specialist analysis tools from the likes of Spirent.  This being so, calculating such additional information gets no more priority within the ‘firmware', than it deserves.  I've seen similar things while calculating the size of the Earth with school kids.  Distance gone on a handheld GNSS receiver odometer rarely exactly matches the accompanying trundle wheel value.  So, was it the sweet little thing reading the handset upside down or the cute kid determined to beat the world trundle wheel racing record. DaveP