Editing Global Positioning System (section)

==== Iterative ====
Both the equations for four satellites, or the least squares equations for more than four, are non-linear and need special solution methods. A common approach is by iteration on a linearized form of the equations, such as the [[Gauss–Newton algorithm]].

The GPS was initially developed assuming use of a numerical least-squares solution method—i.e., before closed-form solutions were found.