Kolesnikov D. Static aperture synthesis method in remote sensing and non-destructive testing problems

The dissertation research is devoted to the statistical optimization of the method of radio image formation of surfaces in radio systems using aperture synthesis technology, under the condition of investigating a static surface area and the sensor's ability to move along a non-linear trajectory. Based on the analysis of the main operations of spatio-temporal signals in the developed optimal method of radio vision of a static surface, the dissertation research developed a structural scheme of a radio system for non-contact measurement of parameters of test surfaces and objects in laboratory conditions. Such systems are proposed for solving issues of remote sensing (creating test images of surfaces, ground structures, aircraft, and various equipment) and non-destructive testing (nodes, devices, aggregates through radio-transparent windows in the bodies, etc.). Thus, the author achieved the goal of the dissertation research – improving the resolution of radar images of test surfaces and objects through statistical optimization of the method of their formation in radio systems with aperture synthesis, moving over a static scene along a non-linear trajectory. The object of the research is the process of forming radar images of a static scene by a radio system moving along a non-linear trajectory. The subject of the research is statistically optimal methods and algorithms of spatio-temporal signal processing in radar systems with aperture synthesis. The need for the research is due to the fact that modern systems for obtaining images of the Earth or space have several disadvantages in relation to the tasks of obtaining high-precision radar images of specific static scenes: large size, significant weight, dependence on orbits and Earth's rotation, inability to obtain images of small scenes, etc. At the same time, existing solutions for obtaining radar images of objects located relatively close to the antenna were based on engineering ideas and experience, rather than on the result of solving optimization problems of radio systems. Therefore, a number of tasks were solved to achieve the goal of the dissertation research. First of all, the mathematical models of coherent and incoherent radar images in systems with aperture synthesis for the case of non-linear movement of the carrier were developed. These models take into account the features of building radio images in the Fresnel and Fraunhofer zones. Models of probing and surface-reflected signals, observation equations, and their correlation properties were developed and studied. According to the criterion of maximum likelihood functional, an optimal algorithm for the formation of coherent radio images of surfaces with the technology of static aperture synthesis was synthesized. The features of the synthesized algorithm include the decorrelation of received oscillations, matched filtering of received signals, and the possibility of using continuous signals without modulation. Optimal and quasi-optimal algorithms were studied. The verification of the obtained algorithm for the formation of radio images was carried out through simulation modeling. As a result, the overall operability and efficiency of the obtained algorithm for the formation of radio images were shown.