In the detailed mode of operation of the synthetic aperture radar (SAR), an improved level of geometric resolution of the terrain in a small frame is achieved. If, however, the frame length exceeds the size of the bottom trace in the azimuthal direction, then it is necessary to use a sliding spotlight operation mode (SSL), in which antenna pattern is scanned in the swath along the azimuth angle. To increase the width of the swath, ScanSAR mode is used. In the traditional implementation of this mode, image serration occurs. This effect can be eliminated by using terrain observation by progressive scans mode (TOPS)). In this mode, when shooting a frame, the antenna pattern runs quickly and alternately through all the specified partial swath bands. Despite the presence of a large number of publications in domestic and foreign literature devoted to the analysis of the main parameters of SAR operating in SSL and TOPS modes, there is a need to clarify calculation methods and increase the number of system parameters issued by them, which generally determine the basic appearance of the equipment. The purpose of the work is to clarify and detail the presentation of the methodology for a priori estimation of an increased number of parameters describing the main system characteristics of space SAR operating in SSL and TOPS. The paper develops and describes in detail a methodology with an exhaustive list of calculation ratios for a priori estimation of parameters describing the main system characteristics of space SAR operating in SSL and TOPS. Based on it, algorithms and software modules have been developed that allow you to perform calculations and display the results in a visual graphical form. Examples of computer calculations of 12 system parameters dependencies on the angle of sight of space radars operating in these two modes are given. The application of the developed methodology makes it possible to quickly perform an a priori assessment of a variety of basic system parameters of space radars operating in SSL and TOPS modes, which facilitates the selection of the most acceptable basic appearance of the equipment for practical implementation.
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