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An object at height h above the ground and slant range R forms an angle α that can be calculated through sin α = h / R.By re-arrangement, R = h / sin α, or R = h csc α. The radar equation states that the signal received from an object, P e, varies inversely with the 4th power of range and directly as the square of the antenna gain, G, such that P e ~ G 2 / R 4.
A typical UWB system might use a bandwidth of one-third to one-half of its center frequency. For example, some systems use a bandwidth of about 1 GHz centered around 3 GHz. The two most common methods to increase signal bandwidth used in UWB radar, including SAR, are very short pulses and high-bandwidth chirping.
A simple calculation reveals that a radar echo will take approximately 10.8 μs to return from a target 1 statute mile away (counting from the leading edge of the transmitter pulse (T 0), (sometimes known as transmitter main bang)). For convenience, these figures may also be expressed as 1 nautical mile in 12.4 μs or 1 kilometre in 6.7 μs.
The civilian microwave landing system uses PESA transmit-only arrays. A PESA contrasts with an active electronically scanned array (AESA) antenna, which has a separate transmitter and/or receiver unit for each antenna element, all controlled by a computer; AESA is a more advanced, sophisticated versatile second-generation version of the ...
Radar systems operating at extremely high frequency offer enhanced Doppler resolution for a given coherent processing interval. [18] This increased resolution allows access to micro-Doppler signatures (MDSs), where micro-Doppler refers to Doppler modulations caused by the oscillatory movement of a target's structural components, in contrast to ...
The Hughes AN/ASG-18 Fire Control System was a prototype airborne radar/combination system for the planned North American XF-108 Rapier interceptor aircraft for the United States Air Force, and later for the Lockheed YF-12. The US's first pulse-Doppler radar, [4] the system had look-down/shoot-down capability and could track one target at a time.
However, since humans reflect far less radar energy than metal does, these systems require sophisticated technology to isolate human targets and moreover to process any sort of detailed image. Through-the-wall radars can be made with Ultra Wideband impulse radar, micro- Doppler radar , and synthetic aperture radar (SAR).
The radar can be mounted on an aircraft's fuselage or on the top inside a small dome. Either position gives the radar 360-degree coverage. Either position gives the radar 360-degree coverage. The phased array radar allows positions of aircraft on operator screens to be updated every 2–4 seconds, rather than every 20–40 seconds as is the ...