D.D. Gabrielyan, V.I. Demchenko, A.A. Kosogor, D.Ya. Razdorkin

Currently the construction of radio systems designed for providing data received from the spacecraft (SC) and for high precision measurements of spacecraft trajectory is widely used monopulse method, based on the use of a corrugated horn for generating sum and difference patterns. The purpose of this paper is implementing systematic analysis of errors arising in determining the position of the spacecraft relative to the electrical axis of the antenna in the monopulse systems high-precision measurements of the angular coordinates associated with the deviation of the parameters of individual devices from the desired values. The main factors affecting the accuracy of the angular coordinates of the spacecraft, in addition to the noise in the sum and difference channels additionally include:  distortion of the pattern sum and difference channels, due to manufacturing errors of the mirror system and the mismatch of phase centers of the corrugated horn on the sum and difference patterns focus reflector antenna;  signal flow channel in the total difference associated with the construction of the coupler fashion and its parameters;  the amplitude and phase mismatch of transmission of sum and difference channels, determined by the parameters of antenna waveguide channel as a whole unit and low-noise amplifiers and frequency converters;  amplitude and phase deviations in the formation of partial channels patterns. In an article in the linear approximation, the relationship components of the measurement errors deviations from the spacecraft equisignal areas with abnormal parameters in the mentioned devices. It is shown that the currently implemented setting accuracy of the amplitudes and phases of the devices discussed in monopulse systems and manufacturing with the feed reflector antenna and horn contribution to the error in determining the angular position of the spacecraft associated with the deviation of the values of the phases of the nominal values equals about of 50%, the contribution to the error associated with the deviation values of the amplitudes of the nominal values equals about of 45% and the contribution to the error due to the deviation of the difference parameters patterns equals about of 5 %. It is noted that in some cases the effect of various errors in devices monopulse system errors in the measurement of the angular coordinates can be mutually compensated. This provides additional possibilities when designing devices monopulse system to reduce measurement errors.