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ECEN5633 Radar TheoryECEN5633 Radar TheoryLecture #28 23 April 2015Lecture #28 23 April 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-eng/scheets/ecen5633www.okstate.edu/elec-eng/scheets/ecen5633
ECEN5633 Radar TheoryECEN5633 Radar TheoryLecture #28 23 April 2015Lecture #28 23 April 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-eng/scheets/ecen5633www.okstate.edu/elec-eng/scheets/ecen5633
Read 6.4Read 6.4 Problems 6.1, Web 15 & 16Problems 6.1, Web 15 & 16 Design Problem ReworkDesign Problem Rework
Due by midnight, 28 April (Live)Due by midnight, 28 April (Live) Due by midnight, 29 April (DL)Due by midnight, 29 April (DL)
Quiz ReworkQuiz Rework Due by midnight, 29 April (Live)Due by midnight, 29 April (Live)
Final Exam Final Exam 0800 – 0950, Thursday, 7 May0800 – 0950, Thursday, 7 May No Later than Thursday, 14 MayNo Later than Thursday, 14 May
Winning DesignWinning Design Replogle & WashbourneReplogle & Washbourne 5.35 GHz center frequency5.35 GHz center frequency 93 element phased array, G = 17,51793 element phased array, G = 17,517 LNA with lowest Temp & Gain = 1,300LNA with lowest Temp & Gain = 1,300 Single Pulse, Coherent DetectionSingle Pulse, Coherent Detection
.9486 of pulse energy captured.9486 of pulse energy captured ChirpChirp
Sweep range of 1.154 MHzSweep range of 1.154 MHz $12.73 Million$12.73 Million
Spread Spectrum RadarSpread Spectrum Radar
Uses > minimum required BWUses > minimum required BW Chirp Radar is a formChirp Radar is a form
PPrr still valid (RF power out of antenna) still valid (RF power out of antenna)
Reduce PReduce Prr by 3 dB prior to calculating P(Hit) by 3 dB prior to calculating P(Hit) Direct Conversion ReceiverDirect Conversion Receiver
Example) Direct Conversion ReceiverExample) Direct Conversion Receiver
2 μwatt
Mixer&
Matched Filter
1/4 watt signalA watts noise
Detector
Standard
2 μwatt
Mixer&
Matched Filter
1/16 watt signalA/2 watts noise
Detector
Chirp
F-22 RaptorF-22 Raptor
Uses Frequency Hopping
Source: Wikipedia
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
X
X
X
X
X
X
Original Clone Overlap
Time
Fre
quen
cy
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
X
X
X
X
X
X
Original No Shift Overlap
5
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
X
X
X
X
X
X
Original 1 Shift Right Overlap
5 0
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
XX
X
X
X
X
Original 1 Shift Right1 Shift Up
Overlap
5 04
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
XX
X
X
X
X
Original 1 Shift Right1 Shift Up1 Shift Left
Overlap
5 040
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
XX
X
X
X
X
Original 1 Shift Right1 Shift Up2 Shifts Left
Overlap
5 0400
Estimating FH AmbiguityEstimating FH AmbiguityContinuingwith this process…(Need 4 more columns & 4 more rows tocomplete).
5 04000 00000
0 0000 0 0
00
00
34
3
X
X
X
X
X
Original
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
X
X
X
X
X
X
Original Clone Overlap
Estimating FH AmbiguityEstimating FH Ambiguity
Original No Shift Overlap
5X
X
X
X
X
X
X
X
X
X
Estimating FH AmbiguityEstimating FH Ambiguity
Original 1 Shift Right Overlap
5 0X
X
X
X
X
X
X
X
X
X
Estimating FH AmbiguityEstimating FH Ambiguity
Original 1 Shift Right1 Shift Up
Overlap
5 00X
X
X
X
X
X
X
X
X
X
Estimating FH AmbiguityEstimating FH Ambiguity
Original 1 Shift Right1 Shift Up1 Shift Left
Overlap
5 000X
X
X
X
X
X
X
X
X
X
Estimating FH AmbiguityEstimating FH Ambiguity
Original 1 Shift Right1 Shift Up2 Shifts Left
Overlap
5 0000X
X
X
X
X
X
X
X
X
X
Estimating FH AmbiguityEstimating FH Ambiguity
Original Overlap
5 00000 20030
3 0000 0 0
02
00
00
0X
X
X
X
X
Continuingwith this process…(Need 4 more columns & 4 more rows tocomplete).
Estimating FH AmbiguityEstimating FH Ambiguity
X
X
X
X
X
Original Overlap
5 01001 01001
0 1010 0 1
00
00
01
0Costas Signal(Need 4 more columns & 4 more rows tocomplete).
Costas Signals FH AmbiguityCostas Signals FH Ambiguity
Overlap(EstimatedAmbiguityFunction)
FH Sequences with 1 FH Sequences with 1 coincidencecoincidence
5*4*3*2 = 120 sequences5*4*3*2 = 120 sequences With 5 hops per pulseWith 5 hops per pulse 1 hop to each frequency1 hop to each frequency
40 possible Costas sequences40 possible Costas sequences Best ChoiceBest Choice
Example: Frequency Hopping Ambiguity Function
Example: Frequency Hopping Ambiguity Function
source: Levanon,, RADAR PRINCIPLESWiley Interscience,, 1988
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