1. 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
4/24/2017
HYPACK® Multibeam Training Seminar

2. 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
4/24/2017
HYPACK® Multibeam Training Seminar

3. 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.
4/24/2017
HYPACK® Multibeam Training Seminar

4. 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
4/24/2017

5. 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
4/24/2017

6. 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.
4/24/2017
HYPACK® Multibeam Training Seminar

7. 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
4/24/2017
HYPACK® Multibeam Training Seminar
Cut On Top of Trackline

8. 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.
4/24/2017
4/24/2017
HYPACK® Multibeam Training Seminar 8 8

9. 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.
4/24/2017
4/24/2017
HYPACK® Multibeam Training Seminar 9 9

10. The New Patch Test Window
4/24/2017
HYPACK® Multibeam Training Seminar 10

11. 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.
4/24/2017
4/24/2017
HYPACK® Multibeam Training Seminar 11 11