Abstract
<jats:p>В статье рассмотрена проблема обеспечения требуемой радиометрической чувствительности бортового радиолокационного комплекса с активной фазированной антенной решёткой, размещаемого на космическом аппарате для дистанционного зондирования Земли, в условиях снижения срока службы приёмо-передающих каналов. Предлагается введение коэффициента коррекции количества работоспособных приёмо-передающих каналов в математическое представление радиометрической чувствительности. Предлагаемое решение направлено на совершенствование существующих подходов к проектированию бортовых радиолокационных комплексов. Применение модернизированного математического представления позволит не только прогнозировать возможное ухудшение радиометрической чувствительности в течение срока активного существования бортового радиолокационного комплекса, но и оценить снижение вероятности правильного обнаружения объектов на радиолокационном изображении.</jats:p> <jats:p>Introduction. Spacecraft equipped with Earth remote sensing (ERS) systems are employed to address a range of tasks, including environmental change monitoring, disaster surveillance, security and defense applications. Such spacecraft acquire information by recording electromagnetic radiation using specialized sensors onboard. An onboard radar system (ORS) can serve as one such sensor. A critical component of a spacecraft's ORS is its antenna device, for instance, an active phased array antenna (APAA). The operation of an ORS in the space environment exposes the equipment to high stress levels due to external factors, including mechanical and thermal loads, as well as climatic and weather conditions. These factors degrade equipment reliability, reducing, among other things, the operational lifetime of transmit/receive modules (TRMs). This study aims at improving existing design approaches for spacecraft ORS with APAA to ensure that specified radiometric sensitivity is maintained throughout the system's operational lifetime, even as TRM service life degrades. Problem Statement. The reliability characteristics of an ORS fundamentally determine its operational performance. A key operational parameter governing the success of an ERS mission is the probability of correct object detection in radar images. This probability depends on image quality metrics, such as radiometric sensitivity and radiometric contrast. This paper proposes an improvement to the existing mathematical representation of radiometric sensitivity by introducing a correction factor for operational TRMs, which varies over the system's operational lifetime. This approach reduces the potential range of radiometric sensitivity deviation throughout the spacecraft's operational lifetime, thereby helping to maintain the required probability of correct object detection in radar images, even as TRM failures occur. Results. An enhancement to the mathematical expression for radiometric sensitivity is proposed, enabling the degradation of TRM service life during spacecraft ORS operation to be accounted for. The introduction of a correction factor for operational TRMs allows for more accurate prediction of radiometric sensitivity degradation and, consequently, the probability of correct object detection in radar images. This approach refines existing spacecraft ORS design principles.</jats:p>