The statement below quoted from User satellite geometry seems to be incompatible with the navigation equations The time for receiver clocks is synchronized with the satellite clocks as a part of the solution process It is certainly true that the receiver location is at the intersection of 3 spheres since it is at the intersection of n spheres where n is greater than 3 It is sometimes incorrectly said that the user location is at the intersection of three spheres While simpler to visualize this is only the case if the receiver has a clock synchronized with the satellite clocks i e the receiver measures true ranges to the satellites rather than range differences There are significant performance benefits to the user carrying a clock synchronized with the satellites Foremost is that only three satellites are needed to compute a position solution If this were part of the GPS system concept so that all users needed to carry a synchronized clock then a smaller number of satellites could be deployed However the cost and complexity of the user equipment would increase significantly Licensed Professional Engineer