Question

2. A search radar operates at 5 GHz by sending 3 MW pulses of 20 uus pulse duration. The gain of the radar antenna is 28 dB and the equivalent system noise temperature is 1400°K. The system loss is 1 dB. The radar cross section of a typical airplane viewed from the front is 30 mp. If the minimum signal-to-noise ratio (SNR) needed for detection is 20 dB, what is the maximum detectable range of the search radar?

Answer 1

Answer Griven; no:1 Page search radar operates at frequency, f = 5 6 Ha. By sending a mw pulses of 20 us pulse duration. Grain radar antenna = 28 dB. Equivalent system noise temperature, T = 1400° K. ४० System doss -IdB. 30 m2 Radar cross section The is to determine the maximum detectable range of search radar. If the minimum to - noise BNR) = 20 dB objective signal-to-noise We know; follows 14. Rmax t = The maximum detectable range ; Rmax és calculated as Pamo (iik1.38 1.38 x10-23) (470)FK To BL (SNR) min o where; f = Receiver noise figure. det us calculate calculate all the terms and substitute them in this equation where; x = 0 espeed of light (C) = 3 x 103 8 Then 3 X 10 i la 5*109 - 0.06 m. Р. = 3 Mw t = 3000W We have Grain; G = 28 dB Loss :|: 100 1,25% : 630.95

.. The receiver noise ne-2 figure is Page f. 1+ To To take: To: 290 Let us By substituting values get. F. + 14 00 290 : 5.829 And we know; B=1/4 ''T = 20 lis. Then; B= 20us. - 54104.Ha (SNR) min = 20 dB 2.0 -10 = 100 Now, Substitute all these values in equation ©, we get Rmax (3000)(630,96)? (0.06)?(30) (47) *(5.827)(1.38X 10^23)(290)(50000) (1.26)(100) 1/4 1/4 128.98 X 106 -10 2.9153 X10 = 25,790 km Maximum detectable range of search radar = 25.790 km