А.А. Volkov – Ph.D. (Eng.), Lecturer, Military Educational-Research Centre of Air Force «Air Force Academy Named After Professor N.E. Zhukovsky and Y.A. Gagarin» (Voronezh)
V.I. Karpuhin – Dr.Sc. (Eng.), Professor, Honored Scientist, Chief Research Scientist, Research Exploring Institute of Radio-Electronic Fight Of Military Educational-Research Centre Of Air Force «Air Force Academy Named After Professor N.E. Zhukovsky and Y.A. Gagarin» (Voronezh)
The major requirement imposed to radar stations with synthesizing of an aperture is high resolving power which defines detail and quality of prospecting information. For ensuring high resolving power various algorithms of autofocusing of a trajectory signal are used. One of the most prime algorithms in realization is the autofocusing algorithm on the basis of an assessment of average Doppler frequency of the accepted signal. This algorithm does not demand existence of dot reflectors in a review zone, and the principles of its work are described in the known literature. At the same time questions of influence of hindrances on effectiveness of autofocusing of this kind are not considered. The work purpose – a research of effectiveness of an algorithm of autofocusing on the basis of an assessment of average Doppler frequency of the accepted signal in the conditions of noise hindrances. As an autofocusing algorithm efficiency factor in the conditions of hindrances the probability of the exact detection of a signal of the purpose in processing devices is chosen. Such choice is caused by the fact that detection of the useful signal always precedes measurement of its parameters. Analytical expressions of probability of detection of the useful signal in channels of processing of the device realizing an algorithm of an assessment of coefficient of square phase distortions are received. Calculations of dependences of probability of detection on the relation a signal hindrance are carried out at various values of a phase mistake at edges of the synthesized aperture. It is established that phase distortions, as well as existence of hindrances, reduce probability of detection. Existence of noise hindrances can lead to failure of autofocusing and impossibility of achievement of high resolving power of the radar image even if their spectral density is lower than energy of the useful signal. At small phase distortions of a trajectory signal for realization of autofocusing the considerable metabolic cost on increase in the relation a signal hindrance is required. At increase in phase errors of costs of autofocusing decrease and become accepted at larger distortions of a phase.
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