15 January 2014 N. de Hilster, The Inverted Heading Calibration: a field case 1/18

N. de HilsterE. Gaikhorst

HSB Workshop Vessel Geometry and Calibrations15 January 2014

The Inverted Heading Calibration:a field case

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Project OutlineProject Outline

Create a copy of the reference Create a copy of the reference marble on the aft weather deck.marble on the aft weather deck.

Required heading accuracy: 3' Required heading accuracy: 3' (0.05°)(0.05°)

While being afloat!While being afloat!

N. de Hilster, The Inverted Heading Calibration: a field case

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Traverse?Traverse?

N. de Hilster, The Inverted Heading Calibration: a field case

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Or direct?Or direct?

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Project SolutionProject Solution

No direct line of sightNo direct line of sightTraversing not possibleTraversing not possibleSolution: the invertedSolution: the invertedheading calibrationheading calibration

N. de Hilster, The Inverted Heading Calibration: a field case

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ImplementationImplementation

dFOG (Geovisie)dFOG (Geovisie)autocollimation set (Starmountain)autocollimation set (Starmountain)

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Autocollimation SetAutocollimation Set

Tilting base for T2Tilting base for T2Groove for FOG pinsGroove for FOG pinsAlignment accuracy: 0.002°Alignment accuracy: 0.002°

N. de Hilster, The Inverted Heading Calibration: a field case

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Autocollimation SetAutocollimation Set

2D prism target2D prism targetAlignment accuracy: 0.002°Alignment accuracy: 0.002°

N. de Hilster, The Inverted Heading Calibration: a field case

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AutocollimationAutocollimation

Rotating bases for FOG and T2Rotating bases for FOG and T2

N. de Hilster, The Inverted Heading Calibration: a field case

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ProcedureProcedure

dFOG for initial pitch and rolldFOG for initial pitch and roll

AABB

N. de Hilster, The Inverted Heading Calibration: a field case

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Physical heading alignmentPhysical heading alignment

ProcedureProcedure

N. de Hilster, The Inverted Heading Calibration: a field case

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dFOG for final pitch and rolldFOG for final pitch and roll

AABB

ProcedureProcedure

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dFOG on the weather deckdFOG on the weather deck

ProcedureProcedure

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Create Master Training Datum Create Master Training Datum MarkersMarkers

ProcedureProcedure

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Repeated on the other side Repeated on the other side

ProcedureProcedure

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ResultResult

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Post Alignment Check with dFOGPost Alignment Check with dFOGIndependent survey of all six markersIndependent survey of all six markersCalculation of parallelism (target: 3')Calculation of parallelism (target: 3')

Vessel dHeading dRoll

1 2.5' (0.72mm/m) 1.0' (0.29mm/m)

2 0.1' (0.02mm/m) 1.5' (0.44mm/m)

3 0.9' (0.25mm/m) 2.1' (0.61mm/m)

Average 1.1' (0.33mm/m) 1.5' (0.45mm/m)

Quality ControlQuality Control

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ConclusionConclusion

Accurate gyro's (FOGs) can be used Accurate gyro's (FOGs) can be used to transfer heading on dynamic to transfer heading on dynamic objectsobjects

Sensors of the highest accuracy are Sensors of the highest accuracy are requiredrequired

Achievable accuracy approximately a Achievable accuracy approximately a third of the FOG specificationthird of the FOG specification

N. de Hilster, The Inverted Heading Calibration: a field case