During the process of manufacture or measuring large components, position and orientation are needed thus; a method based in surveying the surface can be used to describe them. This method requires an ensemble of measurements of fixed points whose coordinates are unknown. Afterwards resulting observations are manipulated to determinate objects position in order to apply surface metrology. In this work, a methodology to reduce uncertainties in surface measuring is presented. When measuring large surfaces, numerical methods can reduce uncertainties in the measures, and this can be done with instruments as such as the Laser Tracker (LT). Calculations use range and angles measures, in order to determinate the coordinates of tridimensional unknown positions from differents surveying points. The purpose of this work, is to solve problems of surface metrology with given tolerances; with advantages in resources and results, instead of making time sacrifices. Here, a hybrid methodology is developed, combining Laser Tracker with GPS theories and analysis. Such a measuring position system can be used in applications where the use of others systems are unpractical, mainly because this kind of measuring instruments are portables and capable to track and report results in real-time, it can be used in virtually anyplace. Simulations to measure panels for the Large Millimetric Telescope (LMT/GTM) in Mexico were done. A first benefit from using this method is that instrument is not isolated from its measuring environment. Instead, the system is thought as a whole with operator, measuring environment and targets. This solution provides an effective way, and a more precise measurement, because it does optimize the use of the instrument and uses additional information to strength the solution.