Study On Deep Water Exit Speed Prediction Of Torpedo Countermeasure - PDF document

UDT 2020 Study On Deep Water Exit Speed Prediction Of Torpedo Countermeasure Decoys UDT 2020 Paper Study on deep water exit speed prediction of torpedo countermeasure decoys Diren ABAT [1] , Ömer BATMAZ [2] Defense Systems Technologies Division Mechanical Technologies Design Department Naval Systems Mechanical Design Team ASELSAN Inc., Anakara, Turkey e-mail: dabat@aselsan.com.tr [1] , obatmaz@aselsan.com.tr [2] Abstract — Exit speed of a torpedo countermeasure decoys/jammers at all water depths is one of the most important parameter for successful launch and safe separation from submarines. Even though it is possible to test and determine this exit speed in shallow/medium depth, it is hard to test and eventually determine this value in deep water environment. Therefore computational and analytical methods with predetermined input parameters should be used for a successful exit speed prediction. Moreover determining this input parameters requires field tests and controlled measurements. In this paper an innovative and gas generator powered launcher design without gas release will be introduced. The field tests and measurements performed with special designed equipment will be presented. The computational and analytical methods to determine exit speed using the results of this tests and measurements are given as well. ZARGANA ™ , Submarine Torpedo Countermeasure 1 Introduction System ensures submarine survivability against torpedo Torpedoes are still the most threatening weapons for attacks by autonomous operation and quick reaction the submarines. They are very quiet and very fast. After capabilities. The main system components are: detection and classification of the threatening torpedo, it is very important to apply the correct countermeasure  Decision Support System and Firing Panel scenario against the torpedo by using countermeasure  Outboard Launchers decoys/jammers. Because of this reality, a countermeasure  Expendable Acoustic Jammers system should provide several chances to the defending  Expendable Acoustic Decoys ship by successful launches of the countermeasure decoys/jammers with high launching reliabilities. Launching reliability is directly dependent to launching The main features of the outboard launchers, which are the effectively programmed and confidently powered of a pre- main focus of this paper, are: assured working countermeasure decoy/jammer at minimum necessary launching speed (safe separation)  Instant reaction when required in a very short reaction time.  Separate launchers for port and starboard  Interface with decoys/jammers Programming effectiveness, powering scenario and  Automatic programming and powering of working assurance of decoys/jammers are not the subject decoys/jammers before deployment of this paper but a summary of the capabilities of  Does not release bubble/gas to environment during ZARGANA ™ [1] Submarine Torpedo Countermeasure System which ensure these reliability requirements launching (silent launch) deserves to be mentioned. The high launching reliability of pre-tested, programmed and powered decoy/jammer requires safe separation from the submarine can be guaranteed by minimum launching (exit) speed at all submarine speeds, maneuvers and depths. Even though it is possible to test and determine this exit speed in shallow/medium depth, it is hard to test and eventually determine this value in deep water environment. Therefore computational and analytical methods with predetermined input parameters should be used for a successful exit speed prediction. Moreover determining this input parameters requires field tests and controlled measurements. In this paper an innovative and gas generator powered launcher design without gas release Fig. 1. ZARGANA™ System

UDT 2020 UDT 2020 Paper Study On Deep Water Exit Speed Prediction Of Torpedo Countermeasure Decoys will be introduced. The field tests and measurements 3 Exit Speed Requirement Analysis performed with special designed equipment will be presented. The computational and analytical methods to For an affective soft-kill defense, the countermeasure determine exit speed using the results of this tests and decoys/jammer should exit the launcher safely (guaranteed measurements are given as well. activation and working) and have enough speed for safe separation from the submarine. The safe separation of the 2 Zargana TM Launchers decoys/and the jammer should be guaranteed at all submarine speeds, maneuvers and depth. In order to assure this safe separation, all submarine maneuvers are ZARGANA ™ Launcher has unique and innovative design investigated (Fig.4) and multiple numbers of 6DOF with gas generator powered launching mechanism. It is simulations are performed. composed of independently operating Launching Units (LU) with configurable number options (Fig.2) which is responsible for launching corresponding unit when The angle of launcher settlement according to the activated and Launcher Module (LM) which carries all the submarine movement axis is also investigated with this LU’s and have interface for submarine integration. simulations to understand the effect of launching angle on the launching safety (Fig.5). Fig. 2. Configurable LU Number Options for ZARGANA™ Launchers Number of LM’s can be configured according to the space available on the submarine outboard. The space available also determines the launching position of the launchers with respect to the submarine propellers which directly affects the launching effectiveness and safety of the system. The LU’s on the LM’s are responsible for launching the decoys/jammers inside when enabled at minimum launching speed at the existed launching depth. Thanks to its innovative and patented design, no bubble or gas is released during launching. Launching energy is obtained by the gas generators inside (the number and the type of the gas generators are not the concern of this paper). A sealed ram plate (Fig.3 (4)) is used to push the unit outside. The decoys/jammers can be programed and in-device test can be executed during operation. Fig. 4. Some Maneuver Alternatives Analyzed for Safe Separation Fig. 3. Single Launching Unit (LU)

UDT 2020 UDT 2020 Paper Study On Deep Water Exit Speed Prediction Of Torpedo Countermeasure Decoys The working principle of the test system is based on measuring the time steps between the two peaks of disturbed magnetic signal (Fig.7).by the magnets on the test decoy (Fig.8). The system is able to take measurements up to 300 m depth. The test system also includes cameras for successful launching observations (Fig.9). Fig. 8. A Sample Signal Data Obtained from the Test Fig. 5. An Example of a Launching Simulation Result from Different Point of Views With the results of similar many simulations, the minimum exit speed is determined and given as a design input for the Fig. 8. Test Decoy further design stages. After the detail design process, prototypes are manufactured and assembled for testing to assure that LU’s are abl e to launch decoys/jammers at predetermined minimum speed. 4 Exit Speed Measurements &Tests After the prototype integration phase, controlled test and speed measurements are put in to practice to determine the exit speed of the decoys/jammers. In order to measure the exit speed at sea water (even though at deep water), a carefully designed testing equipment is used (Fig.6) Induction Coil Magnets Signal Fig. 9. Speed Measurement Test System Fig. 6. Working Principle of the Speed Measurement System