ECEN5633 Radar Theory Lecture #22 2 April 2015 Dr. George Scheets n Read 4.3 n Problems 4.10, Web 8 & 9 n Design Problem due 7 April (Live), 9 April (DL) u Late turn in fee = -1 per working day n Reworked exams due 14 April (Live) n Quiz #2 Results Hi = 13.6, Low = 6.50, Ave = 11.33, σ =2.71

2015 OSU ECE Spring Banquet n Hosted by Student Branch of IEEE n Wednesday, 15 April, at Meditations n Doors open at 5:30 pm, meal at 6:00 pm n Cash Bar n Sign up in ES202 to reserve your seat(s) u $5 if pay in advance (< 8 April) & resume submitted to u $10 on 9 & 10 April. (A $20 value.) n Speakers: Ron Sinnes (Level3, Director IP) & Eric Miller (VYVX, Sports Manager) n Dress is Business Casual n Many door prizes available! u Known best: 8.4" Samsung Galaxy Tab S, two Fluke Multimeters u +6 points extra credit n All are invited! Sponsored in part by:

Coherent Detection n RCVR Local Oscillator PLL seeks echo frequency & phase lock t p = 1 μsec, f c = 10 GHz → 10,000 cycles n Will take some time Some echo energy is lost Matched Filter fed sinusoid until lock F Area around zero n Locked → Matched Filter fed baseband pulse n Best Potential Performance

Non-coherent Detection n RCVR Local Oscillator at transmitted f c n Stationary target with respect to radar Zero doppler, baseband pulse to Matched Filter n Moving target with respect to radar Wide variety of signals fed to Matched Filter n May get almost nothing when sampled n Quadrature Detection If energy not in I channel, it's in Q channel

Ambiguity Function n X(τ,ν) = g(t)g*(t - τ) e j2πνt dt n X(τ,0) = Autocorrelation of complex envelope g(t) = Matched Filter output envelope u at Zero doppler n X(0,ν) = F.T. of signal's magnitude (AM) ∫ -∞ +∞

Ambiguity Function n X(τ,ν) = g(t)g*(t - τ) e j2πνt dt n For most accurate range estimates u Want narrow width along τ (time) axis n For most accurate radial velocity estimate u Want narrow width along ν (frequency) axis n Since X(0,0) = 1 & Volume of |X(τ,ν)| 2 = 1 (if complex E = 1) May not be able to do both ∫ -∞ +∞

Selected e Integrals

Gaussian Pulse Ambiguity Function n t p = 1.0 source: west 5633 notes

Matched Filter Outputs as f d ↑ f d = 1 f d = 2 f d = 3 f d = 5

Rectangular Pulse Ambiguity Function source: skolnik, Introduction to Radar Systems