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.
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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.
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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
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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.
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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.
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27. The New Patch Test Window
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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.
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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
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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
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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
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HYPACK® Multibeam Training Seminar 34

35. HYPACK® Multibeam Training Seminar
Patch Test in Action
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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