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PATCH TEST HYPACK ® MULTIBEAM COURSE 10/11/20141HYPACK® Multibeam Training Seminar.

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Presentation on theme: "PATCH TEST HYPACK ® MULTIBEAM COURSE 10/11/20141HYPACK® Multibeam Training Seminar."— Presentation transcript:

1 PATCH TEST HYPACK ® MULTIBEAM COURSE 10/11/20141HYPACK® Multibeam Training Seminar

2 HYSWEEP ® Calibration of a Multibeam System (Using Statistical Analysis of the collected data. This is not an ‘Exact’ Science) 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.Patch tests are performed after initial installation, and periodically thereafter if sensors are modified, to quantify any residual biases from the initial system alignment. 10/11/20142HYPACK® Multibeam Training Seminar

3 10/11/2014HYPACK® Multibeam Training Seminar3 Four (4) Individual Tests Four (4) Individual Tests Three (3) that determine the physical misalignments of the multibeam transducer (Roll-Pitch- Yaw) 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 One (1) that determines the Latency, or lack of synchronization between the Position and Depth data acquisition What is a PATCH TEST Fore-Aft Axis Vertical Axis Athwartship Axis Latency effect not shown

4 10/11/2014HYPACK® Multibeam Training Seminar4 Patch Test Checklist Measure Equipment Location Offsets with Respect to Boat Reference Point  Measure Equipment Location Offsets with Respect to Boat Reference Point (X – Port/Starboard, Y – Forward/Aft, Z – Vertical) (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.  Locate area to perform Patch Test and “layout” runlines for each Test.  Open HYPACK ® and HYSWEEP ® Survey programs and begin collecting Patch test data. Patch test data.

5 10/11/2014HYPACK® Multibeam Training Seminar5 Roll Test Sonar and MRU alignment relative to vertical. Sonar and MRU alignment relative to vertical. Can cause large depth errors at outer beams. Can cause large depth errors at outer beams.

6 10/11/2014HYPACK® Multibeam Training Seminar6 Latency Test Delay between position fix and data arrival time.Delay between position fix and data arrival time. Can cause Positional ErrorsCan cause Positional Errors Error is independent of multibeam system.Error is independent of multibeam system.

7 10/11/2014HYPACK® Multibeam Training Seminar7 Pitch Test Sonar and MRU alignment relative to vertical. Sonar and MRU alignment relative to vertical. Can cause depth and position errors across the swath. Can cause depth and position errors across the swath.

8 10/11/2014HYPACK® Multibeam Training Seminar8 Yaw Test Sonar and Gyro alignment relative to boat frame.Sonar and Gyro alignment relative to boat frame. Can cause Position Errors.Can cause Position Errors.

9 10/11/2014HYPACK® Multibeam Training Seminar9 When and Why is a PATCH TEST performed After the installation of a Multibeam transducer After the installation of a Multibeam transducer When Performance Test data is poor (More on this later) When Performance Test data is poor (More on this later) Damage or Deterioration to your Mounting Damage or Deterioration to your Mounting Required by Project Specifications Required by Project Specifications Quality Control, not Quality Assurance test … Quality Control, not Quality Assurance test … (similar to bar check of single-beam system) (similar to bar check of single-beam system)

10 Survey Hints and Warnings 10 Hints: Test in the deepest section of the survey area Test in the deepest section of the survey area. Except for Latency, run lines at your normal survey speed Except for Latency, run lines at your normal survey speed. Run each test twice to confirm results. Average multiple tests for final values. Average multiple tests for final values. DGPS Warning: Make sure you have good GPS positioningRTK GPS is recommended Slight position error may lead toPatch Test errors 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. 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.  Latency Test: +/- 0.4 seconds.  Pitch Test+/- 4.4 degrees.  Pitch Test: +/- 4.4 degrees.  Yaw Test+/- 4.3 degrees.  Yaw Test: +/- 4.3 degrees. 10/11/2014HYPACK® Multibeam Training Seminar 10

11 ROLL: - F lat / Smooth deep bottom - O pposite / Reciprocal lines - O pposite / Reciprocal lines - S ame / Equal speeds - S ame / Equal speeds PITCH : - Flat bottom to an object or - Sloped bank feature - Sloped bank feature - O pposite / Reciprocal lines - O pposite / Reciprocal lines - S ame / Equal speeds - S ame / Equal speeds YAW: - 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 LATENCY: - 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 performed 10/11/201411HYPACK® Multibeam Training Seminar

12 Patch Test Lines Single Head Latency: Line C DLatency: Line C D –Same line and direction –Differing speed, sloping bottom (Watch for settlement differences.) Pitch: Line C DPitch: Line C D –Reciprocal lines, sloping bottom. Same Survey speed. Roll: Line A BRoll: Line A B -Reciprocal lines, flat bottom. -Same Survey speed. Yaw: Lines C D, E FYaw: Lines C D, E F –Offset lines, sloping bottom. –Same Survey speed. 10/11/ HYPACK® Multibeam Training Seminar

13 Patch Test Lines YawPitchLatency Typical Slope ‘Shift’ feature for Yaw, Pitch, and Latency Runlines 10/11/201413HYPACK® Multibeam Training Seminar

14 Patch Test Lines Pitch Test Because the Pitch Test runs lines in opposite directions, Squat a Squat issue may come into play, due to a strong current, ‘Flat’ so be sure to extend each Runline well into the ‘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 10/11/201414HYPACK® Multibeam Training Seminar

15 Patch Test Lines YawPitchLatency If Possible, Find areas similar to these for Yaw, Pitch, and Latency Runlines Two Slopes help to better define the Correction Value for the Test being performed 10/11/201415HYPACK® Multibeam Training Seminar

16 10/11/2014HYPACK® Multibeam Training Seminar16 Tilted Head Patch Test Single Head Run the Same lines as you would for Single Head Patch Test ExceptionApproximate Roll Tilt Exception -- Enter the Approximate Roll Tilt for the Multibeam in HYSWEEP Hardware NOTE: Roll Tilt is Positive (+) downward on the Starboard side 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 (-) downward on the Port side 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. TiltedDual Head This is important to know when setting up a Tilted or Dual Head system.

17 Dual Head Patch Test 10/11/2014HYPACK® Multibeam Training Seminar 17 Different geometry of the Heads requires that you overlap the Port and Starboard heads separately. Latency and Yaw still only require 2 lines. 32 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.

18 Dual Head Patch Test 10/11/2014HYPACK® Multibeam Training Seminar18

19 Dual Head Patch Test 10/11/2014HYPACK® Multibeam Training Seminar19

20 10/11/2014HYPACK® Multibeam Training Seminar 20  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.

21 10/11/2014HYPACK® Multibeam Training Seminar21 This may be more difficult than it seems. Try to find existing hydrographic char Try to find existing hydrographic charts Locate the Flatarea needed for the Roll Test Locate the Flat area needed for the Roll Test Locate the Slopedfor the Latency, Pitch, and Yaw Tests. If known, locate an object (sunken boat or car, old bridge pier, rock pile, etc.) and use it. 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. Finding Area to perform a Patch Test

22 10/11/2014HYPACK® Multibeam Training Seminar22 Roll Area Latency & Pitch Area Yaw Area

23 Patch Test Processing 10/11/2014HYPACK® Multibeam Training Seminar23 In MBMAX Load survey lines in pairs (the two pitch lines for example).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.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.The patch test works against a cross section cut through the survey lines. Use Tools menu to Automatically cut a section or,Use Tools menu to Automatically cut a section or, Use “Wrench” icon to Manually cut the section. (Preferred)Use “Wrench” icon to Manually cut the section. (Preferred)

24 “Manually” cut Cross Sections Roll Test Latency Test Pitch Test Yaw Test Data Collection Direction Cut Perpendicular to Runline Cut On Top of Trackline Cut Parallel to and Between the Tracklines Tracklines 10/11/201424HYPACK® Multibeam Training Seminar

25 How the Patch Test Works 10/11/ Good Fit Cross sections overlay well.Cross sections overlay well. Error is at the minimum point.Error is at the minimum point. Poor Fit Cross sections overlay poorly. Large error. Numerical Method The cross sections are calculated at various angle offsets. For example; Pitch offset from -10 to 10 degrees in one degree steps.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.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.Minimum error is usually the correct offset. But not always. 25 HYPACK® Multibeam Training Seminar 10/11/2014

26 The Patch Test Window 10/11/ Select Test Pick the tab corresponding to the test you want to runPick the tab corresponding to the test you want to run. Select Sonar Head For dual head systems, select head 1 or 2For dual head systems, select head 1 or 2 Results Read test results hereRead test results here. Cross Sections Red is the first line, Green is the second.Red is the first line, Green is the second. Error Graph X axis is angle or time adjustment.X axis is angle or time adjustment. Y axis is the error; difference between cross sections.Y axis is the error; difference between cross sections. Vertical Adjustment Moves the first line up or down if needed.Moves the first line up or down if needed. Override Override Select Previous or Next adjustment.Select Previous or Next adjustment. HYPACK® Multibeam Training Seminar 10/11/201426

27 The New Patch Test Window 10/11/201427HYPACK® Multibeam Training Seminar

28 10/11/ Order of Processing: Find the Latency offset firstFind the Latency offset first Apply Latency, then do the Roll test.Apply Latency, then do the Roll test. Apply Latency and Pitch, then do the Pitch test.Apply Latency and Pitch, then do the Pitch test. Apply Latency, Pitch, and Roll, then finish with the Yaw testApply Latency, Pitch, and Roll, then finish with the Yaw test. 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… 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. HYPACK® Multibeam Training Seminar 10/11/201428

29 Patch Test Procedures (Suggested) Max. Resolution Max. Resolution Step Increment # of Steps w/ DGPS w/ RTK GPS Latency Latency Latency Initial Time step of 0.1 second using DGPS for Latency test. Initial Time step of 0.1 second using DGPS for Latency test. Decrease Step Increment while Increasing # of Steps for finer results. Decrease Step Increment while Increasing # of Steps for finer results. 10/11/201429HYPACK® Multibeam Training Seminar

30 Patch Test Procedures (Suggested) Max. Resolution Max. Resolution Step Increment # of Steps w/ DGPS w/ RTK GPS Pitch, Yaw Roll Pitch, Roll, Yaw Roll, Pitch, Yaw Initial Angle Step of 1.0 degree using DGPS for Roll, Pitch and 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. Decrease Step Increment while Increasing # of Steps for finer results. 10/11/201430HYPACK® Multibeam Training Seminar

31 31 Patch Test Procedures  After running the data thru all four (4) Tests, then re-run them all again. them all again.  This is done because you now have “rough” adjustments for all four (4) offsets, and the Patch Test can now produce for all four (4) offsets, and the Patch Test can now produce “finer” results for each. “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 use the smallest two (2) Step Increments and their respective # of Steps. respective # of Steps.  This will produce your “Best Results”.  Keep a record of all past Results, and use their Average 10/11/2014HYPACK® Multibeam Training Seminar 31

32 32 Single Head Minimum Angle step of Minimum Angle step of 0.1 degree 0.1 degree Good overlap in cross sections.Good overlap in cross sections. Good “V-Shaped” error curveGood “V-Shaped” error curve. Roll Test 10/11/2014HYPACK® Multibeam Training Seminar 32

33 33 Dual Head Totally different result for each head Totally different result for each head. Refer to previous Slide for Runline Orientation Roll Test 10/11/2014HYPACK® Multibeam Training Seminar 33

34 34 Adjustment: Patch test change to initial offset. Adjustment: Patch test change to initial offset. Initial Offset: Offset before patch test. From HYSWEEP® Hardware. 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 Final Offset: Offset after patch test. To be included in average for update to HYSWEEP® Hardware. Results 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) 10/11/2014HYPACK® Multibeam Training Seminar 34

35 Patch Test in Action 10/11/2014HYPACK® Multibeam Training Seminar35

36 10/11/2014HYPACK® Multibeam Training Seminar36 Open MB Patch Test 2 Project Project

37 10/11/2014HYPACK® Multibeam Training Seminar37 TestPass #Increment# of StepsDepth ErrorResult Roll Pitch Yaw It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. Initial Test Results of Patch Test -- Project - MB Patch Test 2

38 10/11/2014HYPACK® Multibeam Training Seminar38 TestPass #Increment# of StepsDepth Error Initial Result New Result Roll Pitch Yaw It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. Second Run-thru of Patch Test Project – MB Patch Test 2

39 10/11/2014HYPACK® Multibeam Training Seminar39 TestPass #Increment# of StepsDepth Error Second Result Final Result Roll Pitch Yaw It is being assumed that there is NO Latency because of UTC time-tagging and use of 1PPS box. Final Run-thru of Patch Test Project – MB Patch Test 2


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