patch test hypack ® multibeam course. roll: - f lat / smooth deep bottom - o pposite / reciprocal...

PATCH TESTPATCH TEST

HYPACK ® MULTIBEAM COURSE

ROLLROLL: - : - FFlat / Smooth deep bottomlat / Smooth deep bottom - - OOpposite / Reciprocal linespposite / Reciprocal lines - - SSame / Equal speedsame / Equal speeds

PITCHPITCH: : - Flat bottom to an object or - Flat bottom to an object or - Sloped bank feature- Sloped bank feature

- - OOpposite / Reciprocal linespposite / Reciprocal lines - - SSame / Equal speedsame / Equal speeds

YAWYAW: - Flat bottom to an object or : - Flat bottom to an object or - Sloped bank feature- Sloped bank feature

- Parallel offset lines that are - Parallel offset lines that are run in the Same direction run in the Same direction - Same / Equal speeds- Same / Equal speeds

LATENCYLATENCY: - Flat bottom to an object or : - Flat bottom to an object or - Sloped bank feature- Sloped bank feature

- Same direction lines- Same direction lines - Unequal speeds- Unequal speeds

How is a Patch Test performedHow is a Patch Test performed

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Patch Test LinesPatch Test LinesSingle HeadSingle Head

• Latency: Line C DLatency: Line C D– Same line and directionSame line and direction– Differing speed, sloping bottomDiffering speed, sloping bottom(Watch for settlement differences.)(Watch for settlement differences.)

• Pitch: Line C DPitch: Line C D– Reciprocal lines, sloping bottom. Reciprocal lines, sloping bottom.

Same Survey speed.Same Survey speed.

• Roll: Line A BRoll: Line A B- Reciprocal lines, flat bottom. Reciprocal lines, flat bottom. - Same Survey speed.Same Survey speed.

• Yaw: Lines C D, E FYaw: Lines C D, E F– Offset lines, sloping bottom. Offset lines, sloping bottom. – Same Survey speed.Same Survey speed.

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HYPACK® 2012 Training Seminar

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• This may be more difficult than it seems.This may be more difficult than it seems.

• Try to find existing hydrographic charTry to find existing hydrographic charts

• Locate the Locate the FlatFlat area needed for the area needed for the Roll Test Roll Test

• Locate the Locate the SlopedSloped area for the for the Latency, Pitch, and Yaw Tests. Latency, Pitch, and Yaw Tests. If known, If known, locate an object locate an object (sunken boat or car, old bridge (sunken boat or car, old bridge

pier, rock pile, etc.) and use it. pier, rock pile, etc.) and use it.

• Once you have located an area for your Patch Test, collect Once you have located an area for your Patch Test, collect some some data with your multibeam, over this area , in order that you data with your multibeam, over this area , in order that you

can can properly orient your Patch Test runlines properly orient your Patch Test runlines with the with the bottom bottom features needed. It won’t matter that your offsets are still features needed. It won’t matter that your offsets are still

zero, this is only for your runline setup.zero, this is only for your runline setup.

Finding Area to perform a Patch TestFinding Area to perform a Patch Test

Patch Test LinesPatch Test Lines• Typical Slope ‘Shift’ feature for YawYaw, PitchPitch, and LatencyLatency Runlines


Patch Test LinesPatch Test LinesPitch TestPitch Test

• Because the Pitch Test runs lines in opposite directions, a SquatSquat issue may come into play, due to a strong current, so be sure to extend each Runline well into the ‘Flat’ ‘Flat’ Area

• This will allow you to verify whether a ‘‘vertical’ vertical’ adjustment will need to be made during the Pitch’s Patch Test

• NOT compensating for this ‘vertical’ offset will cause significant errors in the Pitch Test values

Vertical Separation


Patch Test LinesPatch Test Lines• If Possible, Find areas similar to these for YawYaw, PitchPitch, and LatencyLatency Runlines

Two Slopes help to better define the Correction Value for the Test being Two Slopes help to better define the Correction Value for the Test being performedperformed


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Also keep in mind Also keep in mind that your Boat Operator that your Boat Operator will make or will make or BREAKBREAK your Patch Test. your Patch Test.

The more precise The more precise that the Boat Operator that the Boat Operator can run the Patch Test can run the Patch Test lines, the better the lines, the better the results will be. results will be.

Therefore, the Boat Therefore, the Boat Operator should run the Operator should run the Latency, Pitch, and Latency, Pitch, and Roll lines as close to Roll lines as close to Nadir beam over Nadir Nadir beam over Nadir beam, from one passbeam, from one passto the next.to the next.

Yaw LinesYaw Lines• Yaw Yaw Runlines are meant to be Parallel to one another, however, in order to achieve 50% overlap throughout the entire Runline, the Boat Operator should follow the outside edge of the 1st Runline (As shown with the Yellow Line)



Roll AreaRoll Area

Latency & Pitch AreaLatency & Pitch Area

Yaw Area

Patch Test ProcessingPatch Test Processing


In MBMAXIn MBMAX

•Load survey lines in Load survey lines in pairspairs (the two pitch lines for (the two pitch lines for example).example).

•Edit through to Edit through to Area Based Editing. Auto cell size Area Based Editing. Auto cell size in Matrix Setup usually works well.in Matrix Setup usually works well.

Starting the Patch TestStarting the Patch Test

•The patch test works against a The patch test works against a cross cross section section cut through the survey lines.cut through the survey lines.

•Use Tools menu to Use Tools menu to AutomaticallyAutomatically cut a cut a section or,section or,

•Use “Wrench” icon to Use “Wrench” icon to ManuallyManually cut the cut the section. section. (Preferred)(Preferred)

““Manually” cut Cross Sections Manually” cut Cross Sections Roll TestRoll Test Latency TestLatency Test

Pitch TestPitch Test Yaw TestYaw Test

Dat

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Dat

a C

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Cut Perpendicular to RunlineCut Perpendicular to Runline

Cut On Top of TracklineCut On Top of Trackline

Cut On Top of TracklineCut On Top of Trackline

Cut Parallel to and Between the Cut Parallel to and Between the TracklinesTracklines


How the Patch Test WorksHow the Patch Test Works

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Good FitGood Fit

•Cross sections Cross sections overlay welloverlay well..

•Error is at the Error is at the minimum pointminimum point..

Poor FitPoor Fit

•Cross sections overlay poorly.

•Large error.

Numerical MethodNumerical Method

•The cross sections are calculated at variousThe cross sections are calculated at various angle offsetsangle offsets. For . For example; example; PitchPitch offset from -10 to 10 degrees in one degree steps. offset from -10 to 10 degrees in one degree steps.

•An An error value error value is calculated at each offset. Error = average depth is calculated at each offset. Error = average depth difference between cross sections.difference between cross sections.

•Minimum error Minimum error is usually the is usually the correct offsetcorrect offset. But not always.. But not always.

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The Patch Test WindowThe Patch Test Window

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Select TestSelect Test

•Pick the tab Pick the tab corresponding to the test corresponding to the test you want to runyou want to run.

Select Sonar HeadSelect Sonar Head

•For dual head For dual head systems, select head systems, select head 1 or 21 or 2

ResultsResults

•Read test results hereRead test results here.

Cross SectionsCross Sections

•RedRed is the first is the first line, line, GreenGreen is the is the second.second.

Error GraphError Graph

•X axis X axis is angle or is angle or time adjustment.time adjustment.

•Y axis Y axis is the error; is the error; difference between difference between cross sections.cross sections.

Vertical AdjustmentVertical Adjustment

•Moves the first line up or down if needed.Moves the first line up or down if needed.

OverrideOverride

•Select Previous or Next adjustment.Select Previous or Next adjustment.


The New Patch Test WindowThe New Patch Test Window


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Order of ProcessingOrder of Processing::

•Find the Find the LatencyLatency offset firstoffset first

•Apply Latency, then do the Apply Latency, then do the PitchPitch test.test.

•Apply Latency and Pitch, then do the Apply Latency and Pitch, then do the RollRoll test.test.

•Apply Latency, Pitch, and Roll, then finish with the Apply Latency, Pitch, and Roll, then finish with the YawYaw test test.

Patch Test ProceduresPatch Test Procedures

The order that you collect your Patch Test data does NOT make any difference, but the order in which you process it, DOES…

Also keep in mind that your Boat Operator will make or break your Also keep in mind that your Boat Operator will make or break your Patch Test. The more precise that the Boat Operator runs the Patch Test. The more precise that the Boat Operator runs the Patch Test lines, the better the results will be. Patch Test lines, the better the results will be.



(Suggested) Max. Resolution Max. ResolutionStep Increment # of Steps w/ DGPS w/ RTK GPS

0.10 21 0.05 31 Latency 0.02 41 0.01 51 Latency

LatencyLatency

• InitialInitial Time step Time step ofof 0.1 second 0.1 second using DGPS for Latency testusing DGPS for Latency test..

• DecreaseDecrease Step Increment Step Increment while while IncreasingIncreasing # of Steps # of Steps for finer results. for finer results.



(Suggested) Max. Resolution Max. ResolutionStep Increment # of Steps w/ DGPS w/ RTK GPS

1.00 21 0.50 31 Pitch, Yaw 0.25 41 0.10 51 Roll Pitch, Roll, Yaw

Roll, Pitch, YawRoll, Pitch, Yaw

• InitialInitial Angle Step Angle Step ofof 1.0 degree 1.0 degree using DGPS for Roll, Pitch and Yawusing DGPS for Roll, Pitch and Yaw..

• DecreaseDecrease Step Increment Step Increment while while IncreasingIncreasing # of Steps# of Steps for finer results. for finer results.


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After running the data thru all four (4) Tests, then After running the data thru all four (4) Tests, then re-runre-run them all againthem all again..

This is done because you now have This is done because you now have “rough” adjustments “rough” adjustments for all four (4) offsets, and the Patch Test can now for all four (4) offsets, and the Patch Test can now produce produce ““finer” results finer” results for eachfor each..

After this second run-thru, After this second run-thru, repeat for a Third time, repeat for a Third time, but only but only use the smallest two (2) Step Increments and their use the smallest two (2) Step Increments and their respective # of Steps.respective # of Steps.

This will produce your This will produce your “Best Results”.“Best Results”.

Keep a record of all past Results, and use their AverageKeep a record of all past Results, and use their Average04/18/23 HYPACK® 2012 Training Seminar

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Single HeadSingle Head

• Minimum Angle step of Minimum Angle step of

0.1 degree0.1 degree

•Good overlap in cross sections.Good overlap in cross sections.

•Good Good “V-Shaped” “V-Shaped” error curveerror curve.

Roll TestRoll Test

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• AdjustmentAdjustment:: Patch test Patch test change to initial offsetchange to initial offset..

• Initial OffsetInitial Offset:: Offset before patch test. Offset before patch test. From HYSWEEP® HardwareFrom HYSWEEP® Hardware..

• Final Offset: Offset after patch testFinal Offset: Offset after patch test.. To be included in average for To be included in average for update to HYSWEEP® Hardwareupdate to HYSWEEP® Hardware.

ResultsResults

Good.Good. Bad. Bad. You should see a U-shaped error curve. This is the reasoning for the Increase # of Steps.

Some Error Curves

Test Results (from Patch Test window)Test Results (from Patch Test window)

04/18/23 HYPACK® 2012 Training Seminar

patch test hypack ® multibeam course. roll: - f lat / smooth deep bottom - o pposite / reciprocal...

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