PATCH TEST HYPACK ® MULTIBEAM COURSE Pat asked to include USACE regs. for patch testing. I don’t see them here.

How is a Patch Test performed ROLL: - Flat / Smooth deep bottom - Opposite / Reciprocal lines - Same / Equal speeds LATENCY: - Flat bottom to an object or - Sloped bank feature - Same direction lines - Unequal speeds PITCH: - Flat bottom to an object or - Sloped bank feature - Opposite / Reciprocal lines - Same / Equal speeds Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave YAW: - Flat bottom to an object or - Sloped bank feature - Parallel offset lines that are run in the Same direction - Same / Equal speeds 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Patch Test Lines Single Head Latency: Line C D Same line and direction Differing speed, sloping bottom (Watch for settlement differences.) Pitch: Line C D Reciprocal lines, sloping bottom. Same Survey speed. Roll: Line A B Reciprocal lines, flat bottom. Same Survey speed. Yaw: Lines C D, E F Offset lines, sloping bottom. Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Finding Area to perform a Patch Test This may be more difficult than it seems. Try to find existing hydrographic charts Locate the Flat area needed for the Roll Test Locate the Sloped area for the Latency, Pitch, and Yaw Tests. If known, locate an object (sunken boat or car, old bridge pier, rock pile, etc.) and use it. Once you have located an area for your Patch Test, collect some data with your multibeam, over this area , in order that you can properly orient your Patch Test runlines with the bottom features needed. It won’t matter that your offsets are still zero, this is only for your runline setup. 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Patch Test Lines Typical Slope ‘Shift’ feature for Yaw, Pitch, and Latency Runlines Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave 4/15/2017 HYPACK® 2012 Training Seminar

Patch Test Lines Pitch Test Because the Pitch Test runs lines in opposite directions, a Squat issue may come into play, due to a strong current, so be sure to extend each Runline well into the ‘Flat’ Area This will allow you to verify whether a ‘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 Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave Vertical Separation 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Patch Test Lines If Possible, Find areas similar to these for Yaw, Pitch, and Latency Runlines Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave Two Slopes help to better define the Correction Value for the Test being performed 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Also keep in mind that your Boat Operator will make or BREAK your Patch Test. The more precise that the Boat Operator can run the Patch Test lines, the better the results will be. Therefore, the Boat Operator should run the Latency, Pitch, and Roll lines as close to Nadir beam over Nadir beam, from one pass to the next. 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Yaw Lines 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) Will be covered in detail at later session Emphasize that Patch Test is a QC function … NOT a QA operation as is a Performance Test Need be performed only periodically … equipment change. Not a daily event Test question … does not correct Heave 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Roll Area Yaw Area Get students to point out areas for each test, prior to putting the lines on the Map. Latency & Pitch Area 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar Patch Test Processing In MBMAX Load survey lines in pairs (the two pitch lines for example). Edit through to Area Based Editing. Auto cell size in Matrix Setup usually works well. Starting the Patch Test The patch test works against a cross section cut through the survey lines. Use Tools menu to Automatically cut a section or, Use “Wrench” icon to Manually cut the section. (Preferred) 4/15/2017 HYPACK® 2012 Training Seminar

HYPACK® 2012 Training Seminar “Manually” cut Cross Sections Roll Test Latency Test Cut Perpendicular to Runline Cut On Top of Trackline Data Collection Direction Pitch Test Yaw Test Cut Parallel to and Between the Tracklines 4/15/2017 HYPACK® 2012 Training Seminar Cut On Top of Trackline

How the Patch Test Works Numerical Method The cross sections are calculated at various angle offsets. For example; Pitch offset from -10 to 10 degrees in one degree steps. An error value is calculated at each offset. Error = average depth difference between cross sections. Minimum error is usually the correct offset. But not always. Good Fit Cross sections overlay well. Error is at the minimum point. Poor Fit Cross sections overlay poorly. Large error. 4/15/2017 HYPACK® 2012 Training Seminar 13 13

HYPACK® 2012 Training Seminar The Patch Test Window Select Test Pick the tab corresponding to the test you want to run. Select Sonar Head For dual head systems, select head 1 or 2 Results Read test results here. Error Graph X axis is angle or time adjustment. Y axis is the error; difference between cross sections. Cross Sections Red is the first line, Green is the second. Vertical Adjustment Moves the first line up or down if needed. Override Select Previous or Next adjustment. 4/15/2017 HYPACK® 2012 Training Seminar 14 14

The New Patch Test Window 4/15/2017 HYPACK® 2012 Training Seminar 15

HYPACK® 2012 Training Seminar Patch 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… Order of Processing: Find the Latency offset first Apply Latency, then do the Pitch test. Apply Latency and Pitch, then do the Roll test. Apply Latency, Pitch, and Roll, then finish with the Yaw test. 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 lines, the better the results will be. 4/15/2017 HYPACK® 2012 Training Seminar 16 16

HYPACK® 2012 Training Seminar Patch Test Procedures Latency Initial Time step of 0.1 second using DGPS for Latency test. Decrease Step Increment while Increasing # of Steps for finer results. (Suggested) Max. Resolution Max. Resolution Step Increment # of Steps w/ DGPS w/ RTK GPS 0.10 21 0.05 31 Latency 0.02 41 0.01 51 Latency 4/15/2017 HYPACK® 2012 Training Seminar 17

HYPACK® 2012 Training Seminar Patch Test Procedures Roll, Pitch, Yaw Initial Angle Step of 1.0 degree using DGPS for Roll, Pitch and Yaw. Decrease Step Increment while Increasing # of Steps for finer results. (Suggested) Max. Resolution Max. Resolution Step 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 4/15/2017 HYPACK® 2012 Training Seminar 18

HYPACK® 2012 Training Seminar Patch Test Procedures After running the data thru all four (4) Tests, then re-run them all again. This is done because you now have “rough” adjustments for all four (4) offsets, and the Patch Test can now produce “finer” results for each. After this second run-thru, repeat for a Third time, but only use the smallest two (2) Step Increments and their respective # of Steps. This will produce your “Best Results”. Keep a record of all past Results, and use their Average 19 4/15/2017 HYPACK® 2012 Training Seminar 19

HYPACK® 2012 Training Seminar Roll Test Single Head Minimum Angle step of 0.1 degree Good overlap in cross sections. Good “V-Shaped” error curve. 20 4/15/2017 HYPACK® 2012 Training Seminar 20

HYPACK® 2012 Training Seminar Results Some Error Curves Good. Bad. You should see a U-shaped error curve. This is the reasoning for the Increase # of Steps. Test Results (from Patch Test window) Adjustment: Patch test change to initial offset. Initial Offset: Offset before patch test. From HYSWEEP® Hardware. Final Offset: Offset after patch test. To be included in average for update to HYSWEEP® Hardware. 21 4/15/2017 HYPACK® 2012 Training Seminar 21