AbstractThe precise methods applied to adjust plane trilateration nets employ least squares techniques. The observation equations or the condition equations in these known methods are, without exception, non-linear. The linearisation is done by using Taylor's expansion and neglecting all second and higher order terms. The coefficients of the corrections in the condition equations methods are lengthy and complicated.This paper presents a new method in which the condition equations are linear and the coefficients of the corrections are simple and can be easily calculated and checked. In this method the measured distances in trilateration nets are considered as elastic members in an internally redundant framework. Known distances between fixed points are treated as very stiff members in the same framework so that their lengths remain unchanged during the process of the adjustment. If the redundant members have fabrication (i.e. measuring) errors, axial forces must be applied to fit them in the framework. As a result axial forces will develop in all other members causing changes in their lengths. By applying minimum work techniques one can determine these changes in length which are in fact the required corrections of the measured distances.