Issues in Signal Design to Lower Probability of Classification and Identification

Passive Classification and Identification (C/I) depends on the ability of signal processing at an unintended receiver to extract signal features or parameters on which basis objects, emitters or signals may be grouped or differentiated. While several papers in this session concern the types of processing available to extract such features, this paper focuses on the several strategies and techniques available to the designers of signals who wish to lower the probability of successful classification and identification. The design of signals to avoid C/I is shown to involve the judicious use of spread spectrum modulation, encoding controlled by pseudo-random noise codes, adaptivity, signal commonality, selection of frequency band and propagation modes and distortion, among a number of other disciplines listed.