Lecture_4_Radar_Principles(1)

Suckedmerightin returningechoesarereceivedby

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Unformatted text preview: onizer aka the Timer Supplies signals that determine the timing of the transmitted pulses and coordinates action among all circuits in system Establishes PRF of the system Duplexer Duplexer Most radar sets use single antenna for transmission and reception aka the TR switch Allows antenna to be sequentially connected to the transmitter and the receiver Antenna Antenna Receives radio frequency energy from transmitter and radiates it in the form of a highly directional beam – Beamforming – "Tractor beam... Sucked me right in.“ Returning echoes are received by antenna and passed to receiver Display Display Visual indications of the received pulses displayed to operators – Range, azimuth/bearing, elevation – Difference between azimuth and bearing Radar Cross Section Radar Cross Section Radar Cross Section Radar Cross Section Defined as the area intercepting that amount of power which, when scattered equally in all directions, produces an echo at the radar Denoted σ Strictly a characteristic of the target Affects strength of radar return Generally, the larger the object, the larger the cross section Radar Cross Section Radar Cross Section Incident energy – Some gets absorbed as heat – Remainder is reradiated (scattered) in many directions Determined by target size, shape, skin material, aspect angle, polarization, radar carrier frequency Different shapes create different backscatter The Radar Range Equation The Transmit/Receive Capability Transmit/Receive Capability Simplex – one or the other – i.e. – car radio Half­Duplex – both, but not at the same time. – i.e. – “walkie­talkie” or BTB Full­Duplex – both and at the same time – i.e. – telephone system and most shipboard communications. Noise Noise Noise is bad on a communic...
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This document was uploaded on 03/28/2014.

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