Principles of Modern Radar - Volume 2 1891121537

12.14 Problems 585[9] Stimson, G.W., Introduction to Airborne Radar, 2d ed., Part VIII, Radar in Electronic Warfare,SciTech Publishing, Raleigh, NC, 1998.[10] Skolnik, M., Ed., Radar Handbook, 2d ed., Chapter 9, Electronic Counter-Countermeasures,McGraw-Hill, New York, 1990.[11] Adamy, D., EW 101: A First Course in Electronic Warfare, Artech House, Norwood, MA,2001.12.14 PROBLEMS1. A coherent repeater is programmed to produce a RFT that is 1200 m farther in rangefrom the radar than the jammer platform itself. What is the time delay that must begenerated by the jammer’s coherent RF memory to achieve this apparent range delay?What is the rate of variation of this delay, in μs per second, if the RFT is to be perceivedas moving farther away in range at a rate of 300 m/s?2. What is the Doppler offset required to make the RFT motion in Problem 1 appearkinematically consistent to a radar at 10 GHz RF?3. You are assigned to select one of two jamming pods for a specific mission of countering aknown, fixed frequency radar from a SOJ platform. The radar has a waveform bandwidthof 5 MHz. Your two choices of EA pods are a 10-kW, 500-MHz barrage noise jammer,and a 1-kW, 20-MHz responsive spot noise jammer. Which jammer provides the greaterpower spectral density and by how much (in dB)?4. In Problem 3, assume the radar operates at 10 GHz and has an antenna gain toward thejammer of –5 dBi and a system noise figure of 6 dB. What is the JNR of the selectedjammer if it is operating in the sidelobe at a range of 50 km with an ERP at the radarpolarization of 40 dBW?5. Equation 12.10 shows the JSR for a noise jammer from a SSJ platform against amonostatic radar. What would the equation be for a bistatic radar, where R t is the rangeto the target from the transmitting radar platform, and R r is the range to the target fromreceiving radar platform?6. A coherent SSJ operating as a linear repeater must generate a 20-dB JSR RGPO techniqueover a 20-m 2 target against a 10-GHz radar. How much net repeater throughputgain must the jammer have to accomplish this assuming all of its power is going in asingle range-Doppler cell? Assuming the jammer HPA has a peak power of 20 W andis transmitting 5 W at range 100 km, at what range would the HPA be likely to go intocompression, changing the jammer from a linear repeater to a saturated repeater?7. A 10-GHz radar has a peak transmitter power of 10 kW, a main lobe antenna gainof 40 dBi, and a sidelobe gain of approximately –10 dBi. What system sensitivity, indBmi, would the jammer need to detect the radar in the main lobe from 100 km? Whatsystem sensitivity would it need to detect the radar in the sidelobe from 50 km?8. An SSJ repeater has a delayed response of 167 ns relative to the leading edge of thetarget skin return. What is the minimum range resolution needed by the radar, eitherthrough a narrow pulse or pulse compression to be able to resolve the target returnfrom the jammer? What approximate waveform bandwidth does this correspond to?