Investigation of algorithms for preliminary frequency synchronization in a satellite communication receiver in the conditions of a non-geostationary orbit of a spacecraft

The work is devoted to a comparative study of various algorithms for compensating for frequency shift in a single-frequency radio channel under conditions of varying Doppler frequency shift. The resulting characteristics of frequency offset compensation algorithms based on the Fitz method and the least squares method were studied. Using the method of numerical experiment, the accuracy characteristics of the operation of the studied algorithms in situations of constant and changing frequency shifts were obtained. The best accuracy characteristics of the algorithm based on the Fitz method were revealed in comparison with those built on the basis of the least squares method. At the same time, the algorithm based on the least squares method showed satisfactory accuracy characteristics of operation under conditions of changing frequency shift, under which the algorithm based on the Fitz method turns out to be ineffective.