Indeed, in 1979 I was a brand new 2nd Lt and Electrical Engineering graduate and found myself in the GPS Joint Program Office at Los Angeles Air Force Station and understudied a protégé of Col Parkinson's in the systems engineering directorate. I suspect the accuracy concerns the Colonel mentioned (see article) were resolved by use of a sophisticated [Kalman] software filter which neutralizes, for example, real-world atmospheric, electromagnetic, gravity/magnetic fluctuations and relativistic effects. Effectively, a kind of Rosetta Stone for GPS triangulation mechanics. It was truly an honor to have worked with some of these brilliant scientists and engineers.