Selection of the bandwidth of the «raised cosine» shaping filter for navigation meander signals

Abstract

Problem statement. One of the ways to reduce the level of out-of-band radiation when generating navigation signals is to use a "raised cosine" type filter. However, the issues of the formation of meander navigation signals using the "raised cosine" filter have not been fully investigated. In particular, the question of choosing the frequency band of the "raised cosine" type filter remains open. Purpose. Evaluation of the influence of the bandwidth of the "raised cosine" forming filter on the spectral and temporal characteristics, the energy efficiency of the transmitter, as well as the integrity of the structural and temporal parameters of navigation meander signals. Results. Analytical expressions for the pulse characteristic of the "raised cosine" type filter are obtained, taking into account the parameters of meander signals. The influence of the frequency band of the "raised cosine" filter on the distortion of meander signals in the frequency and time domain is estimated by mathematical modeling. It is shown that for the formation of meander signals in the "raised cosine" filters, it is advisable to choose the maximum frequency band, which ensures minimal distortion in the frequency and time domains, the minimum value of the peak factor and the best characteristics of the integrity of the structural and temporal parameters of the signals. Practical significance. The results can be used by specialists in the field of satellite radio navigation in the modernization of global navigation satellite systems.