B.A. Lifanov

At the present time the use of signals with pulse-to-pulse frequency hopping in order to improve range resolution is a perspective on-board development of radar engineering. One can receive a detailed range target portrait when processing such signals, which resolution interval of elements is inversely proportional to the range of frequency tuning. It is very important that the high resolution range when using signals with frequency tuning offers an opportunity to select some air objects from the group, and even to separate some elements of these objects. Since the processing of signals with frequency tuning is directly connected with spectral analysis of complex readings reflected from the signal targets, we can also apply the methods of digital spectral analysis of short data sequences besides the classical discrete Fourier transformation. So as it is possible to use mathematical tools for processing signals with pulse-to-pulse frequency tuning. The purpose of this work is to analyze the possibilities to process short samples of the signals with carrier frequency tuning by the methods of spectral estimation for receiving range portraits. The response reduction process received from the aircraft object is described in this article. It is shown analytically how the distance resolution is changing depending on the frequencies tuning range and their quantity. A mathematical model of the reflected signals and its following processing by spectral estimation methods is represented. The linear-prediction technique for the short-sequence of pulses is described. The investigations result shows that super resolution depends on various factors distorting the estimates of correlation matrices. It is necessary to know what factors bias quantities lead to loss of distance resolution within the directional lobe of Fourier transform so that to receive range portrait. For the signals with frequency tuning factors affecting the possibility of super-resolution are the receivers internal noise. To working out the methods of constructing range portrains in radar systems and the methods of constructing radar systems it is necessary to conduct further investigations of digital methods of the spectral analysis applied to signals with frequency tuning. In the final part of the article the results, obtained for different signal-to-noise are lead, by with the super resolution of signals by the spectral function of a linear prediction is provided