MICROWAVE METHODS OF EARTH REMOTE SENSING AND THE PROSPECTS FOR THEIR USE

Abstract

Microwave remote sensing (RS) allows one to obtain information at any time of day, regardless of solar illumination and in a wide range of meteorological conditions, which gives it an advantage over Earth RS methods using the optical and thermal ranges of electromagnetic radiation. At the same time, the potentialities of microwave methods are not fully utilized in commercial RS spacecraft. This paper analyzes trends in the development of microwave RS aimed at identifying the prospects for the use of these methods in commercial RS satellite constellations. Microwave radiometry, altimetry, scatterometry, and radar imaging are considered. It is shown that, due to government contracts, microwave radiometers will be massively used onboard U.S. small commercial weather satellites in the next few years. On-orbit testing of hyperspectral microwave radiometers, which are also of interest for national security and defense applications, may be expected in the coming years. The use of radar altimeters and scatterometers onboard small satellites is currently technically possible, but not in demand. These instruments are designed primarily for monitoring the ocean surface. The onboard use of altimeters and scatterometers may be caused by the needs of military meteorology and the need to improve the quality of weather forecasts in maritime theaters of war. The most actively developing line of microwave RS is space imagery using synthetic aperture radars. In the last decade, single large-size reconnaissance radar satellites have been replaced by multi-satellite constellations of small spacecraft. Of special interest is the development of operational digital models of the Earth's surface as one of the new areas of radar data application. A transition to higher-frequency bands for imaging, which has been outlined in a number of Chinese companies, will make it possible to achieve a higher spatial resolution at a lower cost.

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