Space-time diversity for active antenna systems
In this chapter, different techniques for improving radar performance in detection, location and classification of targets, through simultaneous transmission of radar signals in different directions, are analysed and discussed. After a brief introduction to the benefits and limitations of wide instantaneous angular coverage, the principles of space-time coding - i.e. sending simultaneously different signals through the different subarrays of a phased-array antenna - are described and illustrated by a few examples, e.g. intra-pulse scanning, circulating pulse or interleaved scanning. Generic techniques for codes optimization are then examined and shown to open the way to space-time adaptivity. A quantitative analysis of diversity gain demonstrates the benefits of high resolution inherent to wideband space-time radar systems, and a tentative classification of space-time codings is proposed. The conclusion emphasizes the benefits to be obtained from those space-time techniques, which will become accessible in near future, taking advantage of the current evolution towards agile front-ends and smart mode management systems for future radars.
Space-time diversity for active antenna systems, Page 1 of 2
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