Now here you Siafu go misquoting me again I did not describe the solution of the navigation equations as the intersection of three spheres I said I clearly understand that the GPS navigation equations consist of n n greater than 3 equations for the surfaces of n spheres and that the solution of these n equations consists of a clock bias and a point at the intersection of these n sphere surfaces This of course implies that the position part of the solution is at an intersection of any three of the n spheres but this is not a description of the solution but instead an implication of the solution Kendall credentials certainly do matter since if you don t have the proper education then you can t understand the material and are certainly unqualified to write Also Kendall pride is a virtue I am very proud that I have received a superior quality of education and that I have had a highly successful engineering career The fact that I have the great virtue of pride does not mean that I do not treat others with respect and civility DVdm you start your post with the word That s This usage of the word that is very vague and ambiguous in this context Also you need to say what you are talking about rather than make some reference