K.Y. Gavrilov - Dr.Sc. (Eng.), Director of Educational Research and Production Center (ERPC), Faculty of Flying Vehicles Radio Electronics, Moscow Aviation Institute (National Research Uneversity). E-mail: gvrk61@mail.ru O.N. Linnikov - Ph.D. (Eng.), Director of Research and Production Center «Designingradar systems», Faculty of Flying Vehicles Radio Electronics, Moscow Aviation Institute (National Research Uneversity). E-mail: olinmai@yandex.ru N.S. Panyavina - Head of the Department of Reliability and Testing, CNIRTI named after academician Berg (Moscow). E-mail: n.reznichenko@gmail.com V.N. Trusov - Ph.D. (Eng.), Vice-Director ofResearch and Production Center «Designingradar systems», Faculty of Flying Vehicles Radio Electronics, Moscow Aviation Institute (National Research Uneversity). E-mail: tvn@radiytn.ru

A method of coherent accumulation of signals with steppedfrequency modulation (SFM) is described. Coherent accumulation of signals assumes compensation of the relative phase shifts of individual SFM pulses when they are totaled in each repetition period. The relative phase shifts of SFM signals can be associated with the movement of the target or the radar,for example, in the case of the synthetic aperture antenna. The method of coherent accumulation of signals is the use of reference filters that provide compensation for the known phase changes of the signals in each pulse repetition period. Presents an example of coherent accumulation of pulses in the case of slowly moving targets (e.g. people) and it is shown that such an accumulation should be carried out before performing the discrete Fourier transform. The algorithm for constructing the reference filter for the case of coherent accumulation of pulses in the synthetic aperture is presented. On the basis of the algorithm is carried out synthesizing radar image of the point reflectors by computer simulation of the path signal. Characteristics of the radar and the parameters of its movement through a rectilinear trajectory is allowed to provide a resolving power in oblique and track the ranges of about 0.08 m. Conducted field experiment with the radar prototype, which resulted in the recording of the trajectory of complex digital signal when the length of the interval synthesizing 56.7 m and the band of the slant range 100 m. The algorithms used to obtain a synthesized radar image of the area of the earth surface. Comparison of the obtained image with a photo of the same area allowed us to analyze the quality of the radar image, i.e. the estimation of the real resolution and image contrast.

 

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