Estimates of the error in setting the angular position of the apparent center of radiation by a matrix simulator, which are, in fact, its systematic error, are considered. It is shown that the cause of the error is the replacement of the simulated point emitter by several points. Analytical relations have been obtained that allow calculating the magnitude of the systematic direction fin-ding error based on the characteristics of the matrix simulator and the radiation pattern of the receiving antenna operating with the matrix simulator of the radio engineering system. It is shown that the considered error is completely determined by the nonlinearity of the direction finding characteristic of the antenna. It is established that the error is most significant when simulating the apparent center of radiation outside the matrix. For the area inside the matrix, the dependences of the maximum error values and their angular positions on the shape of the antenna pattern and the specified position of the radiation point are obtained. The relations allowing to estimate errors depending on the ratio of the angular dimensions of the matrix, the width of the antenna radiation pattern and the coefficients of approximation of its radiation pattern are obtained. The reliability of the obtained results is confirmed by comparison with the results obtained by numerical simulation. The results of the work can be used to solve applied problems related to the development of matrix simulators and simulation complexes based on them, as well as to predict their accuracy characteristics.