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LOGO John W. Franklin 1 "Bistatic radars have fascinated surveillance and tracking researcher for decades. Despite evolution from the early Chain Home radars in Britain to today's coherent multimode monostatic radars, there remains a rich research in bistatic and multistatic applications. The promise of quite receivers, aspect angle diversity, and improved target tracking accuracy are what fuel this interest.“ Mark E. Davis Defense Advanced Projects Research Agency (DARPA) (2007) 2 Presentation Flowchart Bistatic Radar Passive Bistatic Radar Objective: Explore the use of ATSC (HDTV) as a Passive Illuminator via Simulation ATSC (HDTV) Signals Practical Passive Radar Systems 3 Outline Overview Properties of Bistatic Radar Geometry Range Equation Doppler Cross Section Properties of Passive Bistatic Radar The Concept and How it Works Why Passive Radar? Applications Performance Evaluation Signal Processing Practical System Examples FM Digital Video Broadcast High Definition Television Signals ATSC Terrestrial Transmission Standard Research Objective 4 Overview-Bistatic Radar Concepts Bistatic radar may be defined as a radar in which the transmitter and receiver are at separate locations as opposed to conventional monostatic radar where they are collocated. The very first radars were bistatic, until pulsed waveforms and T/R switches were developed Bistatic radars can operate with their own dedicated transmitters or with transmitters of opportunity Radars that use more than one transmitter or receiver or both are referred to as multistatic 5 LOGO 6 Geometry Geometry of a Bistatic Radar is Important - it determines many of the operating characteristics Radar Range Equation Doppler Velocity Equation Radar Cross Section Coverage area Bistatic Angle: Angle between the illumination path and echo path Bistatic Angle vs. Radar Mode β<20 degrees – (Monostatic) 20<β<145 degrees – (Bistatic) 145<β<180 degrees – (Forward/Fence) 7 Monostatic and Bistatic Geometry Monostatic Radar Geometry Bistatic Radar Geometry β<20 degrees 20<β<145 degrees 8 Forward/Fence Geometry Forward/Fence Radar Geometry (limiting case) 145<β<180 degrees 9 Bistatic Radar Range Equation 2 2 2 1 44 r A G r PP e t B tr [ [ Fraction of transmitted power that is reflected to receiver Fraction of reflected power that is intercepted by receiving antenna 2 2 2 1 3 2 )4( rr GGP P Brtt r (Bistatic Radar Equation) where P r is the received signal power P t is the transmit power G t is the transmit antenna gain r 1 is the transmitter-to-target range b is the target bistatic RCS r 2 is the target-to-receiver range G r is the receive antenna gain is the radar wavelength 4 2 r e G A Using: then: Transmitted Power 10 123doc.vn