A Next Generation Self- Locating Datum Marker Buoy€¦ · 5/13/2011 Clearwater Instrumentation,...

5/13/2011 Clearwater Instrumentation, Inc. 1

A Next Generation SelfA Next Generation Self--Locating Datum Marker BuoyLocating Datum Marker Buoy

A smaller, more easily deployed A smaller, more easily deployed and faster reporting SLDMBand faster reporting SLDMB

Gary Williams and Eugene Gary Williams and Eugene ZeygerZeygerClearwater Instrumentation, Inc.Clearwater Instrumentation, Inc.

www.clearwaterinstrumentation.comwww.clearwaterinstrumentation.com


OutlineOutline•• Why do we need SLDMBs? Why do we need SLDMBs?

•• Considerations in specifying and SLDMB.Considerations in specifying and SLDMB.

•• SLDMB dynamics on the ocean surface.SLDMB dynamics on the ocean surface.

•• Making an AMaking an A--size SLDMB.size SLDMB.

•• GPS data and data collection.GPS data and data collection.


Why an SLDMB?Why an SLDMB?•• Finding missing people or assets in the ocean is a Finding missing people or assets in the ocean is a

daunting task.daunting task.

•• The first location reported by a distress call or The first location reported by a distress call or emergency beacon is soon outdated when attempting to emergency beacon is soon outdated when attempting to predict the location of floating objects.predict the location of floating objects.

•• Winds, currents and waves will move and disperse them.Winds, currents and waves will move and disperse them.

•• Without specific knowledge of in situ ocean surface Without specific knowledge of in situ ocean surface conditions, predicting dispersion is next to impossible.conditions, predicting dispersion is next to impossible.


Design Approaches to the SLDMBDesign Approaches to the SLDMB

•• There are at least two ways to specify an There are at least two ways to specify an SLDMB:SLDMB:–– By similarity. Make the SLDMB resemble the By similarity. Make the SLDMB resemble the

objects being tracked. For example, by objects being tracked. For example, by varying the drag shape below the waterline.varying the drag shape below the waterline.

–– Measure the surface current. The SLDMB is Measure the surface current. The SLDMB is designed to accurately follow the part of the designed to accurately follow the part of the water column it inhabits. Drift characteristics water column it inhabits. Drift characteristics are inferred by superimposing special shape are inferred by superimposing special shape considerations upon the current field.considerations upon the current field.


The CurrentThe Current--Following SLDMBFollowing SLDMB•• Surface current circulation models assimilating Surface current circulation models assimilating

tides, meteorology and current offer our best tides, meteorology and current offer our best approximations for dispersion on the ocean surface.approximations for dispersion on the ocean surface.

•• An accurate current following SLDMB can provide a An accurate current following SLDMB can provide a calibrating response for circulations and accurate calibrating response for circulations and accurate information on site conditions.information on site conditions.

•• FVCOM Mass Bay ModelFVCOM Mass Bay Model


Forces Applied to Drifting ObjectsForces Applied to Drifting Objects•• Above the sea surface winds Above the sea surface winds

blow against a floating object. blow against a floating object. Exposed surface area and Exposed surface area and shape (drag coefficient) shape (drag coefficient) determine the strength of those determine the strength of those forces.forces.

•• Any object extending into the Any object extending into the ocean surface layer will be ocean surface layer will be dragged by them. These dragged by them. These currents arise from tides, wind currents arise from tides, wind stress and long term, large stress and long term, large scale circulations.scale circulations.

•• Superimposed on those Superimposed on those currents are the cycloidal, currents are the cycloidal, periodic motions of surface periodic motions of surface waves.waves.


Dynamics of a Floating ObjectDynamics of a Floating Object

•• Physical attributesPhysical attributes–– Shape, drag areaShape, drag area–– Mass distribution, inertiaMass distribution, inertia–– Fluid densityFluid density–– Drag coefficientsDrag coefficients

•• Expression of forcesExpression of forces–– Above the surface: wind drag forcesAbove the surface: wind drag forces–– Below the surface: buoyancy, water drag forces and Below the surface: buoyancy, water drag forces and

wave pressurewave pressure


Dynamics of a Floating ObjectDynamics of a Floating ObjectStatic EquilibriumStatic Equilibrium

•• If the surface is If the surface is absolutely still and the absolutely still and the object is motionless, object is motionless, the object is in static the object is in static equilibrium. The equilibrium. The center of buoyancy is center of buoyancy is directly above the directly above the center of mass. center of mass.


Dynamics of a Floating ObjectDynamics of a Floating Object•• The sea surface is The sea surface is

never in this ideal never in this ideal state: the wind blows, state: the wind blows, waves disturb the waves disturb the surface and currents surface and currents flow.flow.

•• Perturbed away from Perturbed away from static equilibrium, the static equilibrium, the object is vertically object is vertically accelerated by accelerated by buoyancy forces.buoyancy forces.


Dynamics of a Floating ObjectDynamics of a Floating Object•• The volumetric shape The volumetric shape

of the object of the object determines the determines the buoyancy force as a buoyancy force as a function of function of submergence.submergence.

•• For a vertically For a vertically symmetrical object symmetrical object the buoyancy varies the buoyancy varies as the volume along as the volume along the axisthe axis


BuoyancyBuoyancy--Volume RelationshipVolume Relationship


Responses to Displacements from Static Responses to Displacements from Static Equilibrium: Heave (and Heave Frequency)Equilibrium: Heave (and Heave Frequency)

•• Displaced from static equilibrium the floating Displaced from static equilibrium the floating object is acted upon a buoyancy force, heave.object is acted upon a buoyancy force, heave.

•• For a simple volume such as a cylinder, For a simple volume such as a cylinder, buoyancy changes linearly moving away from buoyancy changes linearly moving away from equilibrium (either positively or negatively). The equilibrium (either positively or negatively). The restoring force gradually changes and yields a restoring force gradually changes and yields a slower return toward equilibrium. The heave slower return toward equilibrium. The heave frequency is low. For realistic cylindrical drifters, frequency is low. For realistic cylindrical drifters, spar buoys, the natural heave frequency is often spar buoys, the natural heave frequency is often in the spectrum for wind waves. Consequently, in the spectrum for wind waves. Consequently, wind waves often excite heave in these drifters wind waves often excite heave in these drifters leading to rectification of wave energy into buoy leading to rectification of wave energy into buoy translation.translation.


Responses to Displacements from Static Responses to Displacements from Static Equilibrium: Heave (and Heave Frequency)Equilibrium: Heave (and Heave Frequency)

•• For a complex shape such as a sphere For a complex shape such as a sphere floating at its equator at equilibrium, floating at its equator at equilibrium, buoyancy changes are maximum near the buoyancy changes are maximum near the equator. Small displacements are subject equator. Small displacements are subject to strong restoring forces; for realistic to strong restoring forces; for realistic spherical drifters the heave frequency is spherical drifters the heave frequency is high compared to the wind wave high compared to the wind wave spectrum. Spherical drifters generally spectrum. Spherical drifters generally exhibit damped response to wind waves.exhibit damped response to wind waves.


Some Adverse Consequences of Some Adverse Consequences of HeaveHeave

•• Wave energy rectification.Wave energy rectification.•• Variability of wetted surface. Water drag force Variability of wetted surface. Water drag force

varies as wetted surface varies. Vertical currents varies as wetted surface varies. Vertical currents shear and wave pressure will act differently as shear and wave pressure will act differently as the wetted areas changes. Since the net effect the wetted areas changes. Since the net effect will not sum to zero over a wave cycle, the drifter will not sum to zero over a wave cycle, the drifter will be accelerated or retarded relative to current will be accelerated or retarded relative to current motion.motion.

•• If the drifter closely follows the surface, it will If the drifter closely follows the surface, it will favor minimizing the average force over a wave favor minimizing the average force over a wave period. period.


Drag Area and InertiaDrag Area and Inertia

•• A drifter is propelled along with a current by the A drifter is propelled along with a current by the drag force it exerts; this force is proportional to drag force it exerts; this force is proportional to the wetted crossthe wetted cross--sectional area and its sectional area and its characteristic drag coefficient.characteristic drag coefficient.

•• It is desired that the drag forces be large It is desired that the drag forces be large compared to drifter inertia.compared to drifter inertia.

•• Drift is the extent to which a drifter lags behind Drift is the extent to which a drifter lags behind the average current. This usually is stated to be the average current. This usually is stated to be oneone--half the depth of the drifter.half the depth of the drifter.


The CODE DrifterThe CODE Drifter•• The CODE drifter design The CODE drifter design hashas so far so far

been the best design to optimize been the best design to optimize requirements for minimizing adverse requirements for minimizing adverse forces and thus reduce slip.forces and thus reduce slip.

•• A slightly negatively buoyant hull A slightly negatively buoyant hull contains electronics and battery.contains electronics and battery.

•• Dihedral drag planes provide a large Dihedral drag planes provide a large wetted area; the shape is wetted area; the shape is approximately axially symmetric.approximately axially symmetric.

•• Positive buoyancy is imparted by floats Positive buoyancy is imparted by floats connected by flexible lines to the end connected by flexible lines to the end of the upper spars supporting the drag of the upper spars supporting the drag planes. Hull and drag planes are planes. Hull and drag planes are suspended from these floats.suspended from these floats.


The CODE DrifterThe CODE Drifter

•• Distributed buoyancy keeps drifter parallel Distributed buoyancy keeps drifter parallel to the surface by providing large righting to the surface by providing large righting torque.torque.

•• Since the float lines are flexible, they stay Since the float lines are flexible, they stay on the surface when tilt might raise them on the surface when tilt might raise them off the surface.off the surface.

•• Large effective surface are for large drag Large effective surface are for large drag force compared to inertia. Shape is close force compared to inertia. Shape is close to symmetric.to symmetric.


CODE DriftersCODE Drifters


Littoral Drifter Littoral Drifter –– Variety of CODE Variety of CODE ––Close UpClose Up


Littoral Drifter Littoral Drifter –– Variety of CODE Variety of CODE ––DistanceDistance


ClearSatClearSat--1 in Water1 in Water


First USCG SLDMB SpecificationFirst USCG SLDMB Specification

•• “7/10” CODE drifter. “7/10” CODE drifter. The CODE drifter has The CODE drifter has 1 m square drogue 1 m square drogue planes.planes.

•• To reduce the size of To reduce the size of the drifter the drogue the drifter the drogue planes are .7 mplanes are .7 m

•• GPS locationGPS location•• Argos data Argos data

transmissiontransmission


The Deployment ChallengeThe Deployment Challenge•• This is a good drifters This is a good drifters

but do you want this on but do you want this on the deck in the wind or the deck in the wind or to throw out of aircraft to throw out of aircraft at 150 at 150 ktskts??

•• The challenge is to The challenge is to accomplish selfaccomplish self--reversing reversing oragamioragami: fold : fold the drifter into a the drifter into a compact shape that self compact shape that self deploys into its original deploys into its original form.form.


Clearwater SLDMBClearwater SLDMB

•• Compact form achieved Compact form achieved by articulating drogue by articulating drogue spars and spring spars and spring mounting the antenna.mounting the antenna.

•• Air deployment system to Air deployment system to decelerate after drop and decelerate after drop and ensure vertical entry into ensure vertical entry into the water.the water.


SLDMBSLDMB--II

•• Large size takes up space in storage Large size takes up space in storage areas of restricted size.areas of restricted size.

•• NonNon--standard deployment package. Each standard deployment package. Each deployment venue requires a deployment deployment venue requires a deployment method and certification for safe handling.method and certification for safe handling.

•• Argos Argos


SLDMBSLDMB--III GoalsIII Goals

•• Standard package size and deployment. Standard package size and deployment. This is achieved by a deployment system This is achieved by a deployment system that uses an Athat uses an A--size sonobuoy launch size sonobuoy launch system. system.

•• Elimination of data latency: receive data a Elimination of data latency: receive data a soon as it is available. Iridium SBM soon as it is available. Iridium SBM messaging can deliver SLDMB location messaging can deliver SLDMB location information within minutes. information within minutes.


SLDMBSLDMB--III Design ChallengesIII Design Challenges•• CODE design must fit into a much smaller CODE design must fit into a much smaller

package that weighs less and have a weight package that weighs less and have a weight distribution similar to an Adistribution similar to an A--size sonobuoysize sonobuoy

•• Air deploy safely then unfold once in the waterAir deploy safely then unfold once in the water•• Begin operating immediatelyBegin operating immediately•• Iridium GPS location and SBD data transmissionIridium GPS location and SBD data transmission•• Limited volume for electronics and batteriesLimited volume for electronics and batteries


Data RequirementsData Requirements

•• 10 minute GPS locations sent by SBD for 10 minute GPS locations sent by SBD for the first 24 hours (rapid SAR mode)the first 24 hours (rapid SAR mode)

•• 30 minute GPS locations sent by SBD for 30 minute GPS locations sent by SBD for the next 24 hours (standard SAR mode)the next 24 hours (standard SAR mode)

•• 30 minute GPS locations sent by SBD 30 minute GPS locations sent by SBD every 3 hours for the remainder of buoy every 3 hours for the remainder of buoy life (scientific mode)life (scientific mode)


Clearwater SLDMB SpecificationsClearwater SLDMB Specifications

•• Launch Launch –– Air launch from AAir launch from A--Size Sonobuoy tubeSize Sonobuoy tube–– Air launch from rotary wing aircraftAir launch from rotary wing aircraft–– Launch from any water craftLaunch from any water craft

•• FeaturesFeatures–– Iridium SBD messaging. Latency in minutesIridium SBD messaging. Latency in minutes–– Water activated electronic operation. Immediate notification of Water activated electronic operation. Immediate notification of

activation by SBDactivation by SBD–– 20 channel GPS20 channel GPS

•• DataData–– Day 1. GPS time and position and SBD every 10 minutesDay 1. GPS time and position and SBD every 10 minutes–– Day 2. GPS time and positions and SBD every 30minutesDay 2. GPS time and positions and SBD every 30minutes–– Day 3 and beyond. GPS time and position every 30 minutes, Day 3 and beyond. GPS time and position every 30 minutes,

SBD message every 3 hours.SBD message every 3 hours.


A Smaller, Lighter SLDMBA Smaller, Lighter SLDMB

•• SLDMB II is a CODE SLDMB II is a CODE drifterdrifter

•• The SLDMB II fully The SLDMB II fully deployeddeployed

•• Deployed weight: 8.5 Deployed weight: 8.5 lbs. (3.9 Kg)lbs. (3.9 Kg)


Clearwater SLDMB FeaturesClearwater SLDMB Features

•• Size A Sonobuoy compatible. Fits ASize A Sonobuoy compatible. Fits A--Size Size sonobuoy launch container.sonobuoy launch container.

•• Iridium SBD data transmission for near Iridium SBD data transmission for near real time data return and data latency of real time data return and data latency of minutes.minutes.

•• WaterWater--sensitive electronics activation.sensitive electronics activation.•• Life: 1 weekLife: 1 week


SLDMB is lightSLDMB is light

•• Hull including Hull including electronics and electronics and antenna.antenna.

•• Weight: 8.3 lbs.Weight: 8.3 lbs.


SLDMB is RuggedSLDMB is Rugged

•• All components and battery mechanically All components and battery mechanically secured for shock and vibration protection.secured for shock and vibration protection.


SLDMB SelfSLDMB Self--deploysdeploys

•• Clearwater Clearwater technology developed technology developed for the first SLDMB for the first SLDMB has been perfected in has been perfected in Mod II. SLDMB II selfMod II. SLDMB II self--deploys from compact deploys from compact form to CODE form to CODE configuration.configuration.


SLDMB Packed ConfigurationSLDMB Packed Configuration

•• Drogue panels and antenna collapse for Drogue panels and antenna collapse for compact packaging.compact packaging.


SLDMB Air Deployment SystemSLDMB Air Deployment System

•• During launch from aircraft Sonobuoy tube During launch from aircraft Sonobuoy tube SLDMB II is contained within the Deployment SLDMB II is contained within the Deployment System Cylinder.System Cylinder.

•• Air speed is diminished and entry angle is Air speed is diminished and entry angle is managed by deployment parachute on the DSC.managed by deployment parachute on the DSC.

•• SLDMB II is ejected from the DSC by a waterSLDMB II is ejected from the DSC by a water--activated COactivated CO2 2 life preservation inflation system.life preservation inflation system.

•• The ADS fits inside a standard Sonobuoy The ADS fits inside a standard Sonobuoy Launch Container.Launch Container.


SLDMB Air Deployment SystemSLDMB Air Deployment System

•• SLDMB deployment system with parachute on SLDMB deployment system with parachute on top end of DCS tube.top end of DCS tube.

•• Parachute is packed into the top of the DSC and Parachute is packed into the top of the DSC and is pulled out after it exits the SLC by extractor is pulled out after it exits the SLC by extractor flaps attached to the parachute.flaps attached to the parachute.


SLDMB ParachuteSLDMB Parachute

•• SLDMB parachute is SLDMB parachute is securely fixed to the securely fixed to the outside of the DSC.outside of the DSC.


SLDMB CO2 Extraction SystemSLDMB CO2 Extraction System•• Safety floatation Safety floatation

system actuator for system actuator for COCO22 pressure pressure release. Actuator is release. Actuator is enclosed to prevent enclosed to prevent accidental activation accidental activation from mist, rain, from mist, rain, splashing.splashing.

•• COCO22 gas pressure gas pressure expels wrapped expels wrapped SLDMB from DSC. SLDMB from DSC.


SLDMB Compatible with SLCSLDMB Compatible with SLC


SLDMB Easy to HandleSLDMB Easy to Handle


SelfSelf--DeploymentDeployment


Air DeploymentAir Deployment


Air Deployment Air Deployment -- 11


SLDMB DataSLDMB Data

•• Drifter TracksDrifter Tracks•• Data latencyData latency

–– ArgosArgos–– Iridium SBDIridium SBD


NewfoundlandNewfoundland


Day 1 10 min. GPS and SBDDay 1 10 min. GPS and SBD


Day 1 and 2 Day 1 and 2 -- 30 min. GPS SBD30 min. GPS SBD


All Including 30 min GPS 3 hr. SBDAll Including 30 min GPS 3 hr. SBD


Argos Data LatencyArgos Data Latency


Iridium SBD Data LatencyIridium SBD Data Latency


CODE, SLDMB, SLDMB Next Gen CODE, SLDMB, SLDMB Next Gen CharacteristicsCharacteristics

•• CODECODE–– Mass, 10 kgMass, 10 kg–– CrossCross--sectional area, 1 msectional area, 1 m22

–– Inertia:dragInertia:drag, 10:1, 10:1–– Drogue center, .5 m + .3 mDrogue center, .5 m + .3 m

•• SLDMB (7/10ths CODE)SLDMB (7/10ths CODE)–– Mass, 8 kgMass, 8 kg–– CrossCross--sectional area, 0.7 msectional area, 0.7 m22

–– Inertia:dragInertia:drag, 11:1, 11:1–– Drogue center, .35 m + .3 mDrogue center, .35 m + .3 m

•• SLDMB Next Gen (ASLDMB Next Gen (A--Size)Size)–– Mass, 4 kgMass, 4 kg–– CrossCross--sectional area, 0.4 msectional area, 0.4 m22

–– Inertia:drag,10:1Inertia:drag,10:1–– Drogue center, .3 m + .15 mDrogue center, .3 m + .15 m


ConclusionsConclusions•• A CODE type drifter has been reduced to fit into an AA CODE type drifter has been reduced to fit into an A--

size sonobuoy form factor. size sonobuoy form factor. •• The potential exists for an SLDMB congruent in form and The potential exists for an SLDMB congruent in form and

mass distribution that is certifiable for numerous aircraft. mass distribution that is certifiable for numerous aircraft. Storage and handling will be Storage and handling will be indenticalindentical..

•• Good rapid GPS locations are expected with today’s Good rapid GPS locations are expected with today’s technology.technology.

•• Iridium SBD provides nearly real time access to drifter Iridium SBD provides nearly real time access to drifter GPS locations.GPS locations.

•• Improvements in GPS satellite data transmitters allow Improvements in GPS satellite data transmitters allow enhanced performance (more data) with a smaller enhanced performance (more data) with a smaller package.package.


AcknowledgmentsAcknowledgments

•• CC--Core for funding supportCore for funding support•• Canadian Coast Guard for testing at seaCanadian Coast Guard for testing at sea•• Canadian Forces testing at sea and air Canadian Forces testing at sea and air

drop testing.drop testing.

A Next Generation Self- Locating Datum Marker Buoy€¦ · 5/13/2011 Clearwater Instrumentation,...

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