Turovsky O. Models and methods for increasing the accuracy of operation of phase synchronization systems of satellite telecommunications in the mode of carrier frequency tracking

In the dissertation work the actual scientific and technical problem of development of models and methods of increase of accuracy of work of systems of phase synchronization of satellite telecommunications in a mode of tracking on a carrier frequency is solved. Models and methods of synthesis of the combined system of phase synchronization of coherent demodulators in the mode of monitoring of the carrier frequency in constant and transient modes of operation of satellite telecommunications which allow to synthesize the combined systems of synchronization with essential advantages on speed and accuracy closed type synchronization. To determine the quantitative values of the minimum variance of the carrier frequency estimation of the input signal by coherent demodulators of satellite telecommunications, the criterion of the lower Kramer-Rao boundary is substantiated and the method of its calculation is presented. To estimate the carrier frequency for coherent demodulators in the continuous mode of signal reception by satellite telecommunications, the corresponding method is presented. This technique takes into account the influence of "adjacent" channels of input signals and, with a significantly reduced observation interval, increases the accuracy of carrier frequency estimation by the rule of maximum likelihood using the fast Fourier transform function and the method of phase multiplication of the input signal. taken continuously The method of two - stage carrier frequency estimation for coherent demodulators in the packet mode of signal reception by satellite telecommunications is developed in the work. This technique provides a simple procedure for calculating the first stage of approximate frequency estimation using sliding fast Fourier transform and, thanks to an iterative dichotomous procedure, allows, in the second stage, to significantly increase the accuracy of carrier frequency estimation by reducing observation intervals taking into account the uncertainty of all parameters. received in batch mode. It is shown that the application of the carrier frequency estimation method for a coherent demodulator when receiving a signal in continuous mode for modulation methods FM-2 and FM-4 provides an estimate of the carrier frequency with a variance that is not more than 3 times higher than the corresponding conditions. -Rao in the range of signal / noise from 1 to 6 dB. The proposed method of estimating the carrier frequency by a coherent demodulator when receiving a signal in batch mode provides an estimate with a certain variance at a small observation interval equal to 27 clock intervals and the variance of the frequency estimate almost coincides with the defined lower Kramer-Rao boundary. Hardware implementation of the algorithm for estimating the carrier frequency in the packet mode of signal reception is proposed to perform on modern computing devices, which together with their capabilities and capabilities of the proposed algorithm provide real-time calculations.