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HYPACK® Multibeam Training Seminar

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Presentation on theme: "HYPACK® Multibeam Training Seminar"— Presentation transcript:

1 HYPACK® Multibeam Training Seminar
PATCH TEST HYPACK ® MULTIBEAM COURSE Pat asked to include USACE regs. for patch testing. I don’t see them here. 4/6/2017 HYPACK® Multibeam Training Seminar

2 HYSWEEP® Calibration of a Multibeam System
(Using Statistical Analysis of the collected data. This is not an ‘Exact’ Science) Pat asked to include USACE regs. for patch testing. I don’t see them here. USACE Requirements for Patch Testing (EM ) Patch tests are performed after initial installation, and periodically thereafter if sensors are modified, to quantify any residual biases from the initial system alignment. 4/6/2017 HYPACK® Multibeam Training Seminar

3 HYPACK® Multibeam Training Seminar
What is a PATCH TEST Fore-Aft Axis Vertical Axis Athwartship Axis Four (4) Individual Tests Three (3) that determine the physical misalignments of the multibeam transducer (Roll-Pitch-Yaw) One (1) that determines the Latency , or lack of synchronization between the Position and Depth data acquisition Latency effect not shown 4/6/2017 HYPACK® Multibeam Training Seminar

4 HYPACK® Multibeam Training Seminar
Patch Test Checklist Measure Equipment Location Offsets with Respect to Boat Reference Point (X – Port/Starboard, Y – Forward/Aft, Z – Vertical) Enter these Offsets in their respective Devices in the HYPACK ® and HYSWEEP ® Hardware Programs Leave Roll, Pitch, and Yaw values in the Multibeam’s Device as all Zeros (0.0) (Unless performing a “check” Patch Test for an existing setup.) Leave Latency value in HYPACK ® Navigation as Zero (0.0) (Unless performing a “check” Patch Test for an existing setup.) Locate area to perform Patch Test and “layout” runlines for each Test. Open HYPACK ® and HYSWEEP ® Survey programs and begin collecting Patch test data. 4/6/2017 HYPACK® Multibeam Training Seminar

5 HYPACK® Multibeam Training Seminar
Roll Test Sonar and MRU alignment relative to vertical. Can cause large depth errors at outer beams. 4/6/2017 HYPACK® Multibeam Training Seminar

6 HYPACK® Multibeam Training Seminar
Latency Test Delay between position fix and data arrival time. Can cause Positional Errors Error is independent of multibeam system. 4/6/2017 HYPACK® Multibeam Training Seminar

7 HYPACK® Multibeam Training Seminar
Pitch Test Sonar and MRU alignment relative to vertical. Can cause depth and position errors across the swath. 4/6/2017 HYPACK® Multibeam Training Seminar

8 HYPACK® Multibeam Training Seminar
Yaw Test Sonar and Gyro alignment relative to boat frame. Can cause Position Errors. 4/6/2017 HYPACK® Multibeam Training Seminar

9 When and Why is a PATCH TEST performed
After the installation of a Multibeam transducer When Performance Test data is poor (More on this later) Damage or Deterioration to your Mounting Required by Project Specifications Quality Control, not Quality Assurance test … (similar to bar check of single-beam system) 4/6/2017 HYPACK® Multibeam Training Seminar

10 Survey Hints and Warnings
Test in the deepest section of the survey area. Except for Latency, run lines at your normal survey speed. Run each test twice to confirm results. Average multiple tests for final values. DGPS Warning: Make sure you have good GPS positioning. RTK GPS is recommended. Slight position error may lead to Patch Test errors. If HDOP is high, perhaps best to perform Patch Test at another time. Assuming 3’ DGPS shift in 40’ of water Latency Test: +/- 0.4 seconds. Pitch Test: +/- 4.4 degrees. Yaw Test: +/- 4.3 degrees. Nice graphic! Line separation? 1x depth at shallow end as you stated in another slide? 1½ x depth?—I thought that’s what Pat said. 10 4/6/2017 HYPACK® Multibeam Training Seminar 10

11 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 4/6/2017 HYPACK® Multibeam Training Seminar

12 HYPACK® Multibeam 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 4/6/2017 HYPACK® Multibeam Training Seminar

13 HYPACK® Multibeam 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 4/6/2017 HYPACK® Multibeam Training Seminar

14 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 4/6/2017 HYPACK® Multibeam Training Seminar

15 HYPACK® Multibeam 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 4/6/2017 HYPACK® Multibeam Training Seminar

16 HYPACK® Multibeam Training Seminar
Tilted Head Patch Test Run the Same lines as you would for Single Head Patch Test Exception -- Enter the Approximate Roll Tilt for the Multibeam in HYSWEEP Hardware NOTE: Roll Tilt is Positive (+) when the Head is “rolled” downward on the Starboard side. Therefore, the head is now oriented more to the Port side of the boat. Roll Tilt is Negative (-) when the Head is “rolled” downward on the Port side. Therefore, the head is now oriented more to the Starboard side of the boat. This is important to know when setting up a Tilted or Dual Head system. 4/6/2017 HYPACK® Multibeam Training Seminar

17 HYPACK® Multibeam Training Seminar
Dual Head Patch Test Different geometry of the Heads requires that you overlap the Port and Starboard heads separately. Latency and Yaw still only require 2 lines. Roll and Pitch tests require 3 lines instead of 2. Yaw requires a slightly different spacing and Overlap scheme Some Dual Head systems in engineered mounting frames can be treated as single head. Nice graphic! Line separation? 1x depth at shallow end as you stated in another slide? 1½ x depth?—I thought that’s what Pat said. 4/6/2017 HYPACK® Multibeam Training Seminar

18 HYPACK® Multibeam Training Seminar
Dual Head Patch Test Nice graphic! Line separation? 1x depth at shallow end as you stated in another slide? 1½ x depth?—I thought that’s what Pat said. HYPACK® Multibeam Training Seminar 4/6/2017

19 HYPACK® Multibeam Training Seminar
Dual Head Patch Test Nice graphic! Line separation? 1x depth at shallow end as you stated in another slide? 1½ x depth?—I thought that’s what Pat said. HYPACK® Multibeam Training Seminar 4/6/2017

20 HYPACK® Multibeam 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. 4/6/2017 HYPACK® Multibeam Training Seminar

21 HYPACK® Multibeam 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. 4/6/2017 HYPACK® Multibeam Training Seminar

22 HYPACK® Multibeam 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 4/6/2017 HYPACK® Multibeam Training Seminar

23 HYPACK® Multibeam 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) 4/6/2017 HYPACK® Multibeam Training Seminar

24 HYPACK® Multibeam 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 4/6/2017 HYPACK® Multibeam Training Seminar Cut On Top of Trackline

25 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. 4/6/2017 4/6/2017 HYPACK® Multibeam Training Seminar 25 25

26 HYPACK® Multibeam 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. 4/6/2017 4/6/2017 HYPACK® Multibeam Training Seminar 26 26

27 The New Patch Test Window
4/6/2017 HYPACK® Multibeam Training Seminar 27

28 HYPACK® Multibeam 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 Roll test. Apply Latency and Pitch, then do the Pitch 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. 4/6/2017 4/6/2017 HYPACK® Multibeam Training Seminar 28 28

29 HYPACK® Multibeam 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 Latency Latency 4/6/2017 HYPACK® Multibeam Training Seminar 29

30 HYPACK® Multibeam 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 Pitch, Yaw Roll Pitch, Roll, Yaw 4/6/2017 HYPACK® Multibeam Training Seminar 30

31 HYPACK® Multibeam 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 31 4/6/2017 HYPACK® Multibeam Training Seminar 31

32 HYPACK® Multibeam Training Seminar
Roll Test Single Head Minimum Angle step of 0.1 degree Good overlap in cross sections. Good “V-Shaped” error curve. 32 4/6/2017 HYPACK® Multibeam Training Seminar 32

33 HYPACK® Multibeam Training Seminar
Roll Test Dual Head Totally different result for each head. Refer to previous Slide for Runline Orientation 33 4/6/2017 HYPACK® Multibeam Training Seminar 33

34 HYPACK® Multibeam 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. 34 4/6/2017 HYPACK® Multibeam Training Seminar 34

35 HYPACK® Multibeam Training Seminar
Patch Test in Action 4/6/2017 HYPACK® Multibeam Training Seminar

36 HYPACK® Multibeam Training Seminar
Open MB Patch Test 2 Project 4/6/2017 HYPACK® Multibeam Training Seminar

37 HYPACK® Multibeam Training Seminar
Initial Test Results of Patch Test -- Project - MB Patch Test 2 Test Pass # Increment # of Steps Depth Error Result Roll 1 1.0 21 2.00 2 0.5 31 3 0.2 41 2.40 4 0.1 51 2.60 Pitch -10.00 -14.00 -14.50 Yaw -7.00 -6.00 It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. 4/6/2017 HYPACK® Multibeam Training Seminar

38 Second Run-thru of Patch Test
Project – MB Patch Test 2 Test Pass # Increment # of Steps Depth Error Initial Result New Result Roll 5 0.5 21 2.60 2.10 6 0.2 31 2.30 7 0.1 41 Pitch 4 -14.50 -17.00 Yaw 3 -6.00 -5.50 It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. 4/6/2017 HYPACK® Multibeam Training Seminar

39 Final Run-thru of Patch Test Project – MB Patch Test 2
Pass # Increment # of Steps Depth Error Second Result Final Result Roll 8 0.1 51 2.30 Pitch 5 0.5 31 -17.00 -16.50 Yaw 4 -5.50 It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. 4/6/2017 HYPACK® Multibeam Training Seminar


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