ProblemSet7_2011 - ES3 00 Principles of Naval Weapon...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ES3 00 Principles of Naval Weapon Systems Problem Set 7 — AY2011 1 NAME: {‘3 6% i Instructor/Section / 1) Given the following information: Own ship: Target: Source level: 158 dB Source Level: 122dB Frequency: 3.8 kHz Frequency: 300 Hz Self Noise: 62 dB Broadband Target Strength: 15 dB Directivity Index: 15 dB Range: 8000 m Detection Threshold: -2 dB Environment: Biologics: 67 dB broadband Reverberation level: 45 dB Operating Area: Shipping Lanes Absorption Coefficient: as calculated Seismic Activity: 55dB earthquake (broadband) Transmission Loss Anomaly: 3 dB Wave height: 2 FT 0 Pitfall Prevention: When calculating NL, make sure you pay attention to the frequency of interest. a) For Passive Operations := 5a“ ‘1 2 C} i) Calculate FOMP: ; = #4 ,/ 7c. 7 1, [/4 WU), 5L an, +01 -~oT _———-1 F: i” ‘1’“5‘“) ii) You desire to conduct Passive ASW operations against the target at the given range. Calculate the Passive Transmission Loss estimate: 7;}, (010301) +30 th2 + A c (only $00.) H50 r 5 r5 a 7 ._ 0):] fnJO (01'3’74 iii) Use your info above to determine the Pro a 1 1ty of detection for Passive SONAR Ops: F044? : 4g Q 12 :77? 000 (N’W‘Sgu ‘l’hwh 50X! JetPc‘it‘dfi f,— ~——— b) For Active SONAR operations, ., i) Prove if you are Noise limited or Reverberation limited: ,— 2, L k H; 4/0» A é Z 7) ,_ z (i l’L‘DI—“st’wS-‘S‘fl'fi ‘2 #54; a ‘ I ; 0L0 A/J’Qg Ii ’0 1' f i >/ ii) Calculate the Active FOM: lib/l)! =5L+f§ My; rDJ/‘ID'T fi £153r13 ‘ (335 + iS ~61)? 1'2/.§c1l;) iii) Calculate the Active Transmission loss estimate: : k “ 1 (113 :, , . ., “638) "‘75 ’0 a [Lk T 10 (Of) tSO POI/Z +A> .5 [o (gunk) r ’3'; L 1V5“, fidnf) .1 $ t ‘54? r be .. ,, 2 ,,g.- 7’5 LAQ iv) Use the info above to determine the Probability of detection for Active SONAR Ops: FartT < 12 I. 5 < M 6.4 L m" “00 W0 x- tilt“ (JP'iPC: 'i CO \ c) As the ASWO, which mode of SONAR ops would you recommend and My? pqsgmcl Wmhideifi-t et‘fl'le.“ way, ,mjlt 13 W 8“ 5 My (0.x 0r ES3 00 Principles of Naval Weapon Systems 2) Given the following information: Ownship / Equipment: Active Passive Target Parameters: Source Level 142 dB ------- -- Radiated Acoustic Source Level: 1 17 dB Frequency 3500 Hz 50-1200 Hz Frequency: 400 Hz Self Noise 60 dB :55 dB Target Strength: 17 dB Directivity Index 18 dB l0 dB Max Torpedo Range: 7500 m Detection Threshold -5 dB l5 dB Environment: Snapping Shrimp: 75 dB @ 2.3-3.5 kHz Reverberation Level 60 dB Dolphins: 67 dB Broadband Scattering Loss (A): 8 dB Operational Area: Shipping Lanes Sea State: 4 a) Calculate your passive FOM: fl? ;- Hog Z Ag: : n t “ : é /' .— A l‘ ‘ ' v’) pomp/5L ML 0101 0 fie «~70gd5 b) d) :1 — opsriou-é 5 :0 C9 ' 141.1413 P "at For Active SONAR, are you Noise limited or Reverberation limited? j .77 S [Ark/g It > ' " 01’733482518 < to 4“ Waste -\ 1‘26'7 "s : V l ’3,J®t<3;73g49 J a (26.);(‘13 LAM“ 94 H / Calculate the Active FOM: Pom: 3; ms 4 1H : ’42 H7 «60 {-5, ‘ 10‘! ll“) Given an active 2-way TL of 96dB, show using your answer from c what is your active probability of detection? , . PM »/0 a 7 94 r W» 0 o c EcH‘er ll?“ Given a passive one-way TL of 47 dB, sfiow usmg your a'fl'sWers from a what is your passive robabilit of detection? _ p y Fons” 4/.747‘7:TLP L y , .» D c) («J 6’ SQ MM 50 What mode of SONAR operations do you rm Ark“; ‘5 beiie" of: de lecifom (‘Lmlwe E53 00 11“ CD (I) 0") ca _ C) 06 a“. 3) 4) Principles of Naval Weapon Systems TWO-WAY PROPAGATION LOSS FREQUENCY 3“ 1 500 . HZ ’\ git SOC : {,5 [KYDSfl g) Using the active two—way propagation loss curve above, what is the active Direct Path range and active convergence zone inner and outer ranges (if any). Show all chart work: Direct path 30 kyds lSt Convergence Zone 5 2 inner 4‘3 outer kyds 2“d Convergence Zone lV/t inner IVA outer kyds When using sonobuoys or Variable Depth SONAR (VDS): a) What type of noise is significantly reduced? SELF NOISE b) What does this reduction do to your operational SNR? r 5.:3’L‘. S ‘ N ‘ Ni; [V lMPtovas c) What does an increase in operational SNR do to your probability of target detection? D7” : s - A] La; (may? g alts/I? I2 To meg:- DT; '4’" p E‘DV’ PDEIECT. d) What does VDS allow that a hull-mounted surface SONAR does not? I, KEDuc‘ [3 55L]: NOISE. 2" fl>éLUW Sclulc [a For bi-static SONAR operations: a) Draw a picture showing bi-static operations between a DDG and SH60R (specify which is active/passive): NOISE Di:er [04/ (23%” 126 w [ . l . , a i Cu>c t) law; OUR, 4/1554: j 3 ES3 00 Principles of Naval Weapon Systems 5) For a 2000m long TASS with 401 elements and a frequency response of 30 Hz to 3000 Hz: a) What is the average spacing of the elements in this array? A ‘ L, $000 fr «we —‘ M' I b) How closely spaced must some of the elements be to achieve the high end of the frequency response? If a C 1505. 'g g l / : / o‘sm V’M" Lmax "5000 rrz c) What is the directivity index (DITASS) at the high end of its designed frequency range? : 10 /03 ‘: IO i'qj 1“ ISCUV V / ,_ I, A, ,1 r gomfnz— ’b d) What is the theoretical lowest frequency for the array given its length? Q, ’ I S 00 ;\ from: 1 /. 7 O! lL’ L L 2500 3 e) What is the directivity index (DITASS) at the low end of its designed frequency range? , V - Z a 1 out) : . DI :,Olo\j(%f),10/OJ / /) I‘HB) k Sr) C _ 05".b ' / I i) If a 20 Hz signal is received with a time delay of 0.5 seconds across the entire array, what is the angle off the array axis (0)? L ~ _ = ” ’3 9 1‘ a A5)”:- ,. ' K ’11) x - 0 At- CV (c (A (r),/1P(o> , ACOBCOZSOCJFL >236 g) If you are headed on course 228T, what are the two possible true bearings to the target? 3, = 16067 or 293% 12841“ L937 ,”_—‘—— h) How do you resolve this bearing ambiguity? MCI/Imam la; jLif. Oflc o‘l~ i‘rc, no "\ I, K ’ I. C {‘ 0J7) LV Céomj C. {at 0(17 eh I '7— ‘NW'H 51%27 411‘: ficwkjk 7ch, 0A 6; 7’ f5 (0 AS {‘ch I5 “07 he I. // (QCCJ‘U‘I ...
View Full Document

This note was uploaded on 02/09/2012 for the course WEAPONS AN ES300 taught by Professor Blood during the Summer '11 term at Naval Academy.

Page1 / 4

ProblemSet7_2011 - ES3 00 Principles of Naval Weapon...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online