Qimera Wobble Analysis

How to Start

 

  • Wobble Analysis Tool option of the Tools menu in the Main Menu bar 

What it Does

Qimera provides a wobble analysis tool that allows you to dynamically adjust the echosounder and/or motion sensor configuration in a trial-and-error method to isolate causes of integration errors resulting in so-called "wobbles" in the sounding footprint results.  

General Description

The tool uses the full refraction engine so that the result you see on the screen is the result you will get in processing.  Wobble analysis operations are done using the prioritized motion sensor system.  If you wish to perform an analysis on a secondary system, you must reprioritize these as the primary sensor for the patch test Raw Sonar Files using the Processing Settings dialog and then run the Wobble Analysis again.  This will not overwrite the configuration changes established for the original primary sensor. 

Wobble Analysis Main Application Window

The wobble analysis tool is meant to work in conjunction with the Qimera 4D Scene in the main Qimera application window, this is where the user can choose appropriate spatial subsets of data to examine for the purposes of analysis.  The process begins by selecting one Raw Sonar File from the Qimera Project Sources Dock and then accessing Wobble Analysis Tool under the Tools menu.  The Wobble Analysis Tool automatically draws a Dynamic Selection box in the Qimera 4D Scene centered on the average location of the selected line.  Most of the functionality of Qimera is locked down when running the Wobble Analysis Tool so it is advisable to set view preferences prior to running the tool, for example, setting the color map to Copper to better highlight the color coding of footprint locations and the survey line in the scene.

 

Wobble Analysis Tool Main Window

The majority of the user interaction for a patch test calibration is done in the Patch Test main window.  It has 3 main areas, as described in the Display and Control section below.  A toolbar at the top of the window controls the view of the sounding plot and buttons at the bottom control save and exit of the tool.

Toolbar

 

  Save Button

This button allows you to save a copy of your wobble analysis results to a file which can then be applied to the vessel configuration files associated with all raw sonar files from the same vessel.  This session file is applied to vessel configuration files by either clicking the Apply button or by loading it in the Vessel Configuration Editor.  Applying a configuration change will trigger a reaction from the Dynamic Workflow engine.  When you apply a configuration change, you will be presented with a file selection dialog in which you choose a file path and provide a file name.  This file name will be used to save a wobble analysis session file.  Afterward, you will be presented with a dialog (shown below) which allows you to choose which raw sonar files you would like to apply the configuration change to.  Clicking in the right hand list allows you to perform a standard multiselection.  For files that are imported at a later stage, you must apply the wobble test configuration file to the newly imported files as discussed in the Qimera Vessel Editor documentation.  The tickbox that indicates "Apply to QINSy template file(s)" presently only applies patch test offsets, the option is presented here because this dialog is shared with the Patch Test tool and also the Vessel Editor.

 

  Reset Button

The rest button sets all the slider bars in the dialog to zero.

 

  Zoom Out Button

If you have zoomed into an area of the plot, this button will zoom out to the extents of the currently loaded sounding footprints.

 

  Explore Mode

This is the primary exploration mode of the tool.  As you move your cursor over the plot, the label to the lower left of the sounding plot will update with the current depth/distance of the mouse position.  The distance is the distance relative to the midpoint along the spatial selection box's long-axis.

  Zoom Mode

When in zoom mode, simply click and drag an area of the plot to zoom into.  Or simply single click a location to zoom in a bit on it.  Alt-click a location to zoom out a bit.  Or hit the Home button to return to the full extents of the data.  At any time, you can Shift-Click to drag the plot to a new location.  This is especially useful when you are zoomed in.

  Point Size

Clicking this button will incrementally change the size of the points and lines in your plot area.  If you click and hold the button, it will display a menu where you can select point sizes between Small and XX-Large.

 Dock Options

The view options allow you to configure what you see and how you see it in the sounding plot.

Show Rejected

By default, the patch test tool only plots valid soundings.  If you want to see all soundings, including rejected ones, then enable this option.

Save  to Image

Saves the plot area to an image file (JPEG or PNG)

Show Grid Lines

Show/Hide the grid lines in your plot surfaces.

Display and Control

  1. Sounding Plot:  The sounding plot shows the footprint solutions for the spatial subset chosen in the Qimera 4D Scene for the selected line.  Depth is on the y-axis and distance on the x-axis.  The distance on the x-axis is along the long axis of the spatial selection box from the 4D Scene with zero being the center point along the long axis of the box.

  2. Multibeam Options
    1. Transmit beam is positive forward:  This specifies the sign convention of the transmitter beam angle for sensors that allow for steering of the transmitter beam pattern in the fore-aft direction.
    2. Transmit beam is sonar relative:  This specifies whether beam angles reported by the transmitter are relative to the sonar frame or to the vertical (when they are referenced to the vertical, they are pre-corrected for pitch).
    3. Receive beam is positive starboard: This specifies the sign convention of the receiver beam angle.
    4. Receive beam is sonar relative:  This specifies whether beam angles reported by the receiver are relative to the sonar frame or to the vertical (when they are referenced to the vertical, they are pre-corrected for roll).
  3. Motion Sensor Options
    1. Positive roll port up: This specifies the motion sensor's sign convention for roll.
    2. Positive pitch bow up: This specifies the motion sensor's sign convention for pitch.
    3. Positive heave up: This specifies the motion sensor's sign convention for heave.
    4. Motion Latency: This specifies the motion sensor's time latency in seconds.  
    5. Motion along/across/up position offset: These three allow you to adjust the motion sensor's spatial offset relative to its existing location.  This controls the induced heave effect that occurs when the heave sensor is displaced from the CoG.  Similar dynamic errors can occur if the multibeam sonar head location is in error.  Adjusting the heave sensor location may account for this but it is advisable to review, and if possible resurvey, the sensor locations on the vessel.
    6. Yaw Misalignment: This specifies the angular offset in yaw for the motion sensor, relative to the fore-aft longitudinal axis of the survey platform.  In situations where the motion sensor is misaligned in the ship's reference frame, the roll and pitch signals reported by the sensor can be subject to cross talk.  Adjusting this slider allows you to attempt to solve for the yaw misalignment angle.

Motion sensor adjustment widget

  • Application: this toggles whether or not this adjustment is enabled or disabled.  This is useful for quickly examining before/after scenarios, particularly for screen shots documenting a problem.
  • Offset adjustment spin box: You can enter the offset in the spin box or adjust it using the adjustment arrows that are part of the spin box controller.
  • Offset adjustment slider bar: You can adjust the offset using this slider bar.  Holding down the shift key decreases the sensitivity to mouse movement so that small adjustments can be made to fine tune an offset.
  •    Range edit: Adjust the minimum and maximum range of the slider bar.  The default is to limit this to +/- 1 sec for time offsets and +/-5 meters for location offsets.
  •  Reset zero: Resets the current offset value to zero.

Wobble Analysis Dialog Buttons

Cancel

This button ends the session.  If you have saved a wobble analysis session file, it will remain in the location where you saved it.  No further action will be taken unless you apply the session file using the Vessel Editor.

Apply

This button allows you to save a copy of your wobble analysis results to a file which can then be applied to the vessel configuration files associated with all raw sonar files from the same vessel.  You will be presented with a file selection dialog in which you choose a file path and provide a file name.  This file name will be used to save a wobble analysis session file.  Afterward, you will be presented with a dialog (shown below) which allows you to choose which raw sonar files you would like to apply the wobble analysis results to.  Clicking in the right hand list allows you to perform a standard multiselection.  For files that are imported at a later stage, you must apply the wobble analysis configuration to the newly imported files as discussed in the Qimera Vessel Editor documentation.

 

 

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