Underwater Detection and Tracking Systems

1. Underwater Detection and Tracking Systems Naval Weapons Systems

2. Format for Lecture • Terms, systems • Pictures, slide recognition • BG Operations

3. Basic Sonar Systems • Active • Echo Ranging Systems • Passive • Listening Systems

4. Transducer Theory • Transducer: Device for converting one form of energy into another. • In sonar, electrical energy is transformed into acoustic energy (oscillation of water molecules through which sound travels) • Three ways to change electrical energy into acoustic energy....

5. Searchlight SONAR • SLOW Search • Easily Saturated • Have to TRAIN the transducer • Old Knox class FF’s and before

6. Scanning Echo Ranging SONAR • 360 degree search on each transmission • Range and Bearing on a number of targets • No Mechanical rotation, electronic • Greater Power

7. Advantages & Disadvantages of Sonar Types • Limitations of sonar due to the physical properties of sound travel in water • Active vs Passive sonar in detection • Active vs Passive sonar in tracking

8. Other Sonar Equipment • Tactical Towed Array Sonar (TACTAS) • Sonobouys • Passive • Active • Special purpose • Dipping Sonar • Sound Surveillance System (SOSUS) • VISUAL!

9. Magnetic Anomaly Detection(MAD) • Principle: A metallic submarine disturbs the magnetic lines of force of the earth. • The magnetic distortion - or anomaly - caused by a sub below the surface can be detected from the air above the sub. • P-3, SH-60B

10. Underwater Communications • AN/WQC-2 • Short range • Most of the time, they just surface and use RF

11. Doppler Shift • Oh no, not again!!! • Same principles apply to sound in water • Doppler shift not as great as in the air • Varies with the speed of sound • Increased frequency? • Decreased frequency?

12. EMCON • EMCON for USW! • Similar to RADAR and RF • Set quiet ship • Reduce self noise!

13. Introduction (Platforms) • Surface Ships (DDG, CG, DD, FFG) • Advantages: • more available manpower • greater time on station • variety of detection equipment • variety of available weapons and better fire control systems • ability to operate in foul weather • embarked LAMPS aircraft

14. Introduction (Platforms) • Surface Ships • Disadvantages: • NOT “in” the submarine’s environment • Relatively Slow • Noisy • ASW prosecution is protracted

15. Introduction (Platforms) • Aircraft Carriers • Advantages: • NONE • Disadvantages: • Same as for Surface Ships • Aircraft Carrier is a High Value Target, its importance to naval operations requires many assets to be employed to protect it.

16. Introduction (Platforms) • Aircraft (S-3, P-3, SH-60B) • Advantages: • Speed • ability to deploy sensors over a large area • Surprise through use of passive detection systems • Not in submarine’s environment • Altitude increases radar horizon.

17. Introduction (Platforms) • Aircraft • Disadvantages: • Low time on station • Limited weapons capacity • Limited range • Vulnerable to weather

18. Introduction (Platforms) • Submarines • Advantages: • Shares the advantages of the target • passive detection • concealment • less distracted by sound refracting properties of water • Speed vs. Surface Ships • Nuke subs can stay submerged for months

19. Introduction (Platforms) • Submarines • Disadvantages: • To detect targets, subs must run deep • To communicate, subs must be in shallow water • Capable of high speed, but at the expense of increased noise levels • Diesel subs must “snorkel” to recharge batteries

23. Questions?