The authors consider the principle of geodetic definitions using inertial systems in the absence of signals from satellite radio navigation systems and insufficient density of the initial geodetic base. A technique of improving the coordinates’ accuracy determining using inertial geodetic systems is proposed. Compensation of these systems’ errors is performed through joint equalization of data received from the inertial system, gyrotheodolite and rangefinder. In order to test the methodology, a mathematical model of the ground object movement with an inertial geodetic system was compiled. The simulation results confirm the suitability of the developed methodology. A full-scale experiment was conducted to test the efficiency of the technique. Its results are consistent with those of the simulation. The analysis of the data obtained enables concluding that the developed technique provides an increase in the accuracy of determining coordinates using inertial geodetic systems in the absence or distortion of signals from satellite radio navigation systems and insufficient density of the initial geodetic base. That is why it can be used in operational geodetic training under conditions of autonomy.