Abstract: The article presents the results of the analysis of the error in calculating the coordinates of a mobile subscriber using three Wi-Fi access points, based on measuring the received signal power. The purpose of the study was to develop a geographic system for large storage facilities and a preliminary assessment of the accuracy of calculations in conditions close to real ones. The principles of local and global positioning based on the measurement of various physical characteristics of signal propagation were considered, a method was selected for the implementation of a positioning system. The authors developed a test bench layout of a map on the IEEE 802.11 standard mobile network and software for solving this problem using the trilateration mechanism. To simulate the surrounding electromagnetic environment, a parameter imitating additive white Gaussian noise was added to the calculation formulas. In the course of the work, graphical dependences of the error of measuring the coordinates of the object on the signal / noise ratio in the channel and on the distance from the reference access point are obtained. The results showed that even in the worst operating conditions, the developed system surpasses most systems on the market in terms of measurement accuracy.