steve65@suddenlink.net said: > The phrase "over-determined clock solution" is used in the Trimble > Thunderbolt user manual in describing operation of the Thunderbolt GPS > receiver. > What does "over-determined clock solution" mean? You are trying to solve for X, Y, Z, and T. (or the polar equivalents) 4 unknowns takes 4 equations. You get one equation from each satellite, so you need 4 satellites to get an answer. If you have more satellites, you have more information than you need, hence the solution is over-determined. -- These are my opinions. I hate spam.