1. ECEN5633 Radar Theory Lecture #28 23 April 2015 Dr. George Scheets www.okstate.edu/elec-eng/scheets/ecen5633 n Read 6.4 n Problems 6.1, Web 15 & 16 n Design Problem Rework u Due by midnight, 28 April (Live) u Due by midnight, 29 April (DL) n Quiz Rework u Due by midnight, 29 April (Live) n Final Exam u 0800 – 0950, Thursday, 7 May u No Later than Thursday, 14 May

2. Winning Design n Replogle & Washbourne n 5.35 GHz center frequency n 93 element phased array, G = 17,517 n LNA with lowest Temp & Gain = 1,300 n Single Pulse, Coherent Detection u.9486 of pulse energy captured n Chirp u Sweep range of 1.154 MHz n $12.73 Million

3. Spread Spectrum Radar n Uses > minimum required BW n Chirp Radar is a form u P r still valid (RF power out of antenna) u Reduce P r by 3 dB prior to calculating P(Hit) F Direct Conversion Receiver

4. Example) Direct Conversion Receiver 2 μwatt Mixer & Matched Filter 1/4 watt signal A watts noise Detector Standard 2 μwatt Mixer & Matched Filter 1/16 watt signal A/2 watts noise Detector Chirp

5. F-22 Raptor Uses Frequency Hopping Source: Wikipedia

6. Estimating FH Ambiguity X X X X X X X X X X OriginalClone Overlap Time Frequency

7. Estimating FH Ambiguity X X X X X X X X X X OriginalNo Shift Overlap 5

8. Estimating FH Ambiguity X X X X X X X X X X Original1 Shift Right Overlap 5 0

9. Estimating FH Ambiguity X X X X X X X X X X Original1 Shift Right 1 Shift Up Overlap 5 0 4

10. Estimating FH Ambiguity X X X X X X X X X X Original1 Shift Right 1 Shift Up 1 Shift Left Overlap 5 0 4 0

11. Estimating FH Ambiguity X X X X X X X X X X Original1 Shift Right 1 Shift Up 2 Shifts Left Overlap 5 0 4 0 0

12. Estimating FH Ambiguity Continuing with this process… (Need 4 more columns & 4 more rows to complete). 5 0 40 0 00 0000 000 0 0 00 0 0 0 0 3 4 3 X X X X X Original

13. Estimating FH Ambiguity X X X X X X X X X X OriginalClone Overlap

14. Estimating FH Ambiguity OriginalNo Shift Overlap 5 X X X X X X X X X X

15. Estimating FH Ambiguity Original 1 Shift Right Overlap 5 0 X X X X X X X X X X

16. Estimating FH Ambiguity Original 1 Shift Right 1 Shift Up Overlap 5 0 0 X X X X X X X X X X

17. Estimating FH Ambiguity Original 1 Shift Right 1 Shift Up 1 Shift Left Overlap 5 0 0 0 X X X X X X X X X X

18. Estimating FH Ambiguity Original 1 Shift Right 1 Shift Up 2 Shifts Left Overlap 5 0 0 00 X X X X X X X X X X

19. Estimating FH Ambiguity Original Overlap 5 0 00 0 02 0030 300 0 0 00 0 2 0 0 0 0 0 X X X X X Continuing with this process… (Need 4 more columns & 4 more rows to complete).

20. Estimating FH Ambiguity X X X X X Original Overlap 5 0 10 0 10 1001 010 1 0 01 0 0 0 0 0 1 0 Costas Signal (Need 4 more columns & 4 more rows to complete).

21. Costas Signals FH Ambiguity Overlap (Estimated Ambiguity Function) n FH Sequences with 1 coincidence n 5*4*3*2 = 120 sequences u With 5 hops per pulse u 1 hop to each frequency n 40 possible Costas sequences u Best Choice

22. Example: Frequency Hopping Ambiguity Function source: Levanon,, RADAR PRINCIPLES Wiley Interscience,, 1988