Asset Management Made Easier SonarBell Passive Acoustic Marker Speaker : John Pepper

Transcription

1 Asset Management Made Easier SonarBell Passive Acoustic Marker Speaker : John Pepper

2 SonarBell Provenance SonarBell developed by UK MoD Defence Science Technology Laboratories (DSTL) to provide: A highly efficient & non magnetic sonar target Easy to handle Minimal maintenance Can be tuned to resonate at a specific frequency - or multiple frequencies Multiple Echo Response Better value than alternatives

3 SonarBell Technology The SonarBell works through the constructive interference of sound waves when they meet after transiting the shell and core It is totally passive and omni-directional. Maximum target strength varies from -3dB to -10dB across the range of 4kHz to 700kHz for a 200mm sphere The frequencies at which this phenomena occurs depends on the thickness of the shell The range depends on the size of the SonarBell and the frequency of the sonar

4 Requirement Sonar Reflector Ability to see at range 0 2km Ability to detect over and above reverb Very distinctive echo structure not found naturally Environmentally inert / stable Limited acoustic energy in the water Quick / easy to measure Accurate Ability to locate in absolute coordinates Import locations in to a GIS Unique acoustic signature Manage position of asset throughout life cycle (up to 25 years)

5 Ampliude (V) SonarBell Measurements 6 4 Point A Point B How to Measure distance with SonarBell SonarBell has a two echo response See graph (Time history) First echo (Point A) o o Front face of unit Low level Second Echo (point B) o o Inside shell face High level focused return Use second echo because :- Higher levels detectable over longer distances E E E E E E Time (s) 200mm

6 Ampliude (V) Distinguishing between different diameters Distinguishing between different SonarBells acoustically, is made easier by changing the outer diameter of the SonarBell E E E E E E Time (s) The acoustic diameter can be found by measuring the time difference between the front and back echo. 50mm 200mm

7 Detecting SonarBells unique echo Sonar data structure Process feature 1 SonarBell characterised by unique features Process feature 2 Process feature 3 Process feature 4 Searches for unique features to label SonarBell and geo-reference it Process feature n SonarBell locations

8 Raw sonar data Detection software in use Detection Software Raw data turned off; detections left on

9 SonarBell frequency response Each SonarBell unit can be customised to give the following results: Calibrated to a target strength at a required frequency A broadband frequency response A single / multiple frequency response peaks Coated to only respond at certain frequencies Top Image: Indicates the ability to have a general broadband signal response. Bottom Image: (red- front reflection / blue is rear echo) designed to provide peak response.

10 Target Strength (db) Target Strength (db) SonarBell Calibrations Frequency (khz) Front Echo Back Echo

11 Target Strength (db) Independent validation 0 200mm SonarBell Target strength validated by Frequency (khz) PhD student: Alan Islas Cital PhD supervisor: Philip Atkins

12 Case Studies

13 Defence and Security applications SonarBell Underwater Mine Marking System (SUMMS) A totally passive device with a very low non-acoustic signature - ideal device for marking mines or other objects for destruction. SonarBell Performance and Training System (SPATS) Knowing the effective range of a swimmer detection sonar is vital if interception teams are to be effective - SonarBells as range markers provide that knowledge. SonarBell Equipment Tracking System - (SETS) Passive tracking of underwater vehicles for in-service position monitoring and asset recovery. SonarBell Entry, Exit And Recovery System - (SEEARS) Supporting combat swimmers during the entry, exit and recovery operational phases and marking the location of equipment.

14

15 Commercial Market applications cont... Fishing: 1.4 million commercial (<12m LOA) fishing vessels Supports fishing operations, net / pot and trap recovery Plans to make SonarBell a legal requirement for commercial fishing gear in EC Sensor Calibration: Accurate target strength up to -3dB target strength Simple calibration of MBES systems without need for reference site Supporting major manufactures e.g. Kongsberg, Reson, Atlas Wreck Marking: 116,880 wrecks listed worldwide Accurate location ofvaluable artefacts (including GPS positioning) Supporting UK listed wrecks management, conservation and recreation

16

17 Marine Archaeology Countess of Erne SonarBell

18 Commercial Market applications cont... Scientific instrument location: Marking and identifying scientific environmental equipment During deployment e.g. BAS, GHD and Oceaneering Aids through project management and future recovery of asset Subsea pipes and cables: Site selection, planning, deployment, maintenance, retrieval and disposal of assets Operational support for seismic, geo-physical and hydrocarbon related projects

19 Monitoring the Movement of Subsea Cables Initial Survey Subsequent survey

20 SALT s Customer Portfolio

21 Questions?