Modern radar systems face numerous challenges due to requirements of robust, high performance across multiple missions and multiple functions in the face of dynamically changing environments. Cognitive radar has emerged over the past 15 years through synergy of cybernetics, waveform diversity, and knowledge-aided signal processing as a new vision for the future of radar systems that can address these challenges. This article provides an overview of the historical context and mechanisms for cognitive processing in engineering systems, which have driven an evolution in the definition, analysis, and design of cognitive radar. A survey of cognitive radar research trends is given to provide insight on applications and techniques, while technical and practical challenges to future progress are discussed.
