A method and system is provided for determining a location for each of a plurality of units, which is selected from one of multiple sets of locations, which are each estimated based upon different initial location estimates. The selected set of locations includes the set which has the minimum error value, where the error value is based on the aggregate of the differences between the range determined from the estimated locations and the measured range. By using different sets of initial location estimates, there is a greater chance that at least one of the sets of initial location estimates will avoid any local minimums and produce a more accurate estimate of unit locations.