Principles of Modern Radar - Volume 2 1891121537

530 CHAPTER 12 Electronic Protectionin which superior knowledge of an opponent’s capabilities is paramount to the ultimateoutcome.The purpose of this chapter is to provide a brief introduction to the topic of EP withprimary emphasis to its application to countering active EA. The field of EP is broad andcomplex and well beyond the scope of this chapter, even in an introductory form. Specificdetails associated with fielded EW capabilities are necessarily sensitive and thereforeexcluded from open publication. It is possible, however, to gain insight into the diversityof the topic through exposure to some of the fundamental concepts and examples presentedin this chapter. Several books available in the public domain, listed at the end of the chapter,provide a very thorough treatment of the field of EW in general as well as EP in particular.12.1.1 OrganizationThe subsequent sections of this chapter are organized as follows. Section 12.2 presentsa brief overview of EA. Section 12.3 presents formulas for analyzing relative strength ofjammer energy to target signal energy for different types of jammers. Section 12.4 providesa top-level overview of EP. Sections 12.5 through 12.10 present a sampling of common EPconcepts, categorized based on their most closely associated radar subsystem—antenna,transmitter, exciter, receiver, signal processor, and data processor. Section 12.11 summarizesthe various EP concepts described and lists examples of applicable EA techniques.Sections 12.12 and 12.13 provide recommendations for further reading and specific referencescited in the text. Section 12.14 provides exercises that reinforce some of the keyconcepts presented in the chapter.12.1.2 Key Points• Electronic attack is intended to degrade or deny radar measurements in range, Doppler,and angle dimensions through noise and deceptive interference.• Noise jammers reduce radar sensitivity, while coherent jammers, by preserving radarphase information, inject false targets and erroneous track information.• An important measure of the jammer effectiveness is the ratio of jamming energy totarget signal energy in the radar detection cell—the jam-to-signal ratio.• Radar EP is potentially implemented anywhere in the radar system including the antenna,transmitter, exciter, receiver, signal processor, and data processor.• Radar EP techniques generally attenuate or separate the jamming relative to the targetsignal in various signal domains, including spatial, temporal, and spectral.• Common EP features include sidelobe attenuation, waveform diversity, high averageradiated power, wide dynamic range, range resolution, and track consistency tests.• The diversity and complexity of EW requires careful consideration of the anticipatedEA and ES operational conditions in selecting the appropriate EP design for a radar.12.1.3 NotationKey variable names and symbols used in this chapter are defined in the following list.Symbol DefinitionB radar waveform bandwidthjammer noise bandwidthB j