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Radar equation review

Radar equation review. 1/19/10. Radar eq (Rayleigh scatter). The only variable is h, the pulse length Most radars have a range of h values. Rewrite the radar eq as:. Convert to log form:. Radar equation, Mie scatter. Uses of the radar equation. Convert P r to Z

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Radar equation review

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  1. Radar equation review 1/19/10

  2. Radar eq (Rayleigh scatter) The only variable is h, the pulse length Most radars have a range of h values. Rewrite the radar eq as: Convert to log form:

  3. Radar equation, Mie scatter

  4. Uses of the radar equation • Convert Pr to Z • Used for specifications, such as minimum detectable signal (minimum detectable reflectivity at some standard range) • The general form of the radar equation also applies to sodars and lidars

  5. Important radar parameters • Wavelength (cm vs mm) • Peak transmit power • Pulse vs. continuous wave (CW) • Pulse length • Pulse repetition frequency • Beam width • Minimum detectable signal • Duty cycle: PW/PRT or Pavg/Ppeak • Receiver bandwidth • Antenna size (gain) • Scan rate

  6. Lidar equation • But, additional terms representing absorption and extinction are important.

  7. Beam width estimate For D = 8 ft (2.44 m): if = 3.2 cm, then  = 1.27(0.032)/2.44 * 57.3 = 0.95 deg if  = 8.6 mm, then  = 1.27(0.0086)/2.44 * 57.3 = 0.26 deg For D = 2 ft (0.61 m): if  = 3.2 mm, then  = 1.27(.0032)/0.61 * 57.3 = 0.38 deg 3.2 cm 9.4 GHz 8.6 mm 35 GHz 3.2 mm 94 GHz These are estimates; need to conduct test on antenna range to get actual value

  8. Radial profile of Zmin for WSR-88D Range (km) r = 2 km At 50 km: Z = 58.4 dB + (-107 dBm) +20 log10(50) = -20.6 dBZ. At 10 km: Z = 58.4 +(-107) + 20log10(10) = -28.6 dBZ. end

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