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The radar "looks" with the looking angle θ (or so called off-nadir angle). The angle α between x-axis and the line of sight (LOS) is called cone angle, the angle φ between the x-axis and the projection of the line of sight to the (x; y)-plane is called azimuth angle. Cone- and azimuth angle are related by cosα = cosφ ∙ cosε.
Nadir also refers to the downward-facing viewing geometry of an orbiting satellite, [2] such as is employed during remote sensing of the atmosphere, as well as when an astronaut faces the Earth while performing a spacewalk. A nadir image is a satellite image or aerial photo of the Earth taken vertically.
Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antennas can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions (multiple boresights). [1]
Diagram of AN/SPY-3 vertical electronic pencil beam radar conex projections. X band functionality (8 to 12 GHz frequency range) is optimal for minimizing low-altitude propagation effects, narrow beam width for best tracking accuracy, wide frequency bandwidth for effective target discrimination, and the target illumination for SM-2 and Evolved Sea Sparrow Missiles (ESSM).
Once the radar can "look down", it is subsequently desirable to "shoot down". Various weapons systems (including guns and missiles) are then employed against designated radar targets, either relying on the aircraft's radar employing the "look down" capability (as in semi-active radar homing) or the weapon's own active radar to resolve the indicated target (as in active radar homing).
USA TODAY map details how much snow has accumulated over the past 24, 48, and 72 hours as well as seasonal totals across the US.
With daily themes and "spangrams" to discover, this is the latest addicting game to cross off your to-do list before a new one pops up 24 hours later.
Radar echoes, showing a representation of the carrier. Pulse width also determines the radar's dead zone at close ranges. While the radar transmitter is active, the receiver input is blanked to avoid the amplifiers being swamped (saturated) or, (more likely), damaged.