SIDE SCAN SURVEY 1

Sidescan Survey

Window for Display and control (1) Title Area (1) Title Area – Will display file name with HSX extension. (2) Alarm Indicators: Green = All systems running OK = Yellow = Caution – Bad value from sensor. Check sensor Red = Danger – No data received from sensor. Stop logging to determine cause (4) Boat or Towfish Information: data to be displayed. (note: all data is logged, this just shows the data for display purposes) (3) System Measurements: Towfish altitude, last ping number and time, etc

Options and menus Sidescan Survey runs simultaneously with HYPACK Survey. When Survey starts (with Ctrl-S), HYSCAN will automatically be triggered to start recording. Stopping survey (with Ctrl-E), will stop Sidescan survey. Data files are stored in the Project’s..\Raw folder with an HSX extension. Logging Option: File Overlap. Allows for data to be appended to an HSX file that creates a data overlap when a new Start Line command is issued while already on-line. XTF logging option. (Not recommended. If you want XTF files, collect them as HSX and then use the HSX CONVERTER to export them to XTF.

Sidescan TOOLS Many sidescan systems can be controlled inside SIDE SCAN SURVEY. Many sidescan systems can be controlled inside SIDE SCAN SURVEY. In the Tools menu, select Sidescan Device Control. In the Tools menu, select Sidescan Device Control. Settings for Range, Scale, Pinging, and certain gain controls can be sent to the sonar. Settings for Range, Scale, Pinging, and certain gain controls can be sent to the sonar. Sample control boxes for different sonars

Sidescan Waterfall Toolbar Icons Display controls (also with Shift-F9) Signal window Capture image Height measurement tool Bottom tracking Speed compensation Gain control toggle switch Shortcut to Tools dialog box Display of sonar data Display of sonar data Separate waterfall and signal window for second sonar frequency Separate waterfall and signal window for second sonar frequency Targeting with double click on contact Targeting with double click on contact Capture sonar with camera icon Capture sonar with camera icon Use tools in menu bar or right click in waterfall display to bring up options

Sidescan Signal Window Sidescan signal in “scope” display. Raw signal (from sonar)Raw signal (from sonar) Processed signal (after scaling and gains).Processed signal (after scaling and gains). Single or Multiple PingsSingle or Multiple Pings Display will show HYSCAN gain setting (blue line overlay) Side Scan Signal window, shown with AutoTVG filter active

Adjusting Saturation Levels The sonar image can be enhanced by adjusting the ‘Saturation Level’ bars in the Sidescan Signal window.. The raw signal data is logged to the HSX file.Adjusting saturation levels or gain settings is a display gain setting only. There is affect on the logged data. The raw signal data is logged to the HSX file. Port and Starboard channels can be set independently. The RESET button can be used to adjust the level the best fit setting of the sonar data. (note: when surveying varying areas, use the RESET more often to adjust the signal level)

Display Control - Colors Select colors: Gray scale (for old times) One of the pre-defined palettes or a “Custom” hue Inverted display option (Note difference in shadows) Brightness and Contrast adjustments. Reset button, similar to that in the signal window. Restores settings to a “best fit” signal saturation value (blue bars in signal window).

Display Control - Gain Separate adjustments for each transducer, or can be tied together. GAIN: Controls overall brightness. TVG: Compensates for signal loss with distance or on sloped bottom. ADVANCED TVG: AutoTVG – sensitivity controls TVG as a function of dBs/100 meters Use P1, P2 P3 formula

Gain Toggle switch and Speed Compensation  Toggle switches on the main waterfall for imagery gain control is a shortcut to getting to the Sidescan control page (Shift-F9) Gain Toggle switch – AutoTVG and dB/100m Toggle switch for waterfall Speed compensation

Examples of Different Gain and TVG Settings to the Same Side Scan Image Auto TVG – Sigma = 7 Raw Data: Gain = 0 Use the gain controls to enhance the image, and to balance the signal. No changes are made to the data in the HSX file. Display in waterfall with no adjustments. Notice the darken area near nadir, and the lighten area on the outer edge

Display Control - Display Display Options Remove water column Ideal for mosaicking data Show bottom tracking Shown as blue trace on display Draw range lines at selected interval Range units are always in meters Override sonar range setting on display. A setting of 0 = full range. Use to clip outer portion of data Select Channel for port or starboard only display.

Maintaining a Proper Bottom Track is critical The bottom track during survey operations provides a visual display of how close the towfish is to the bottom. If you see something like this… Speed up or pull the cable in fast! Why removing the bottom track isn’t a good idea.

Display Control – Bottom Tracking 3 methods to use while surveying Obtaining the best bottom track during survey will save time when processing 1. HYSCAN: Bottom track done by HYSCAN 2. Fish Sensor: Use altitude from towfish. 3. None: Set manually. Used when there is a lot of noise or debris in the water column and the bottom cannot be tracked with other options Options for HYSCAN Blanking: Minimum fish altitude.Blanking: Minimum fish altitude. (skips area close to surface) Gate Size: Maximum step change.Gate Size: Maximum step change. Sensitivity: Bottom detect threshold, level 1 – 11. (level 11 is most sensitive)Sensitivity: Bottom detect threshold, level 1 – 11. (level 11 is most sensitive) Option to use 2 nd Frequency ( applicable when using a dual frequency system ) for Bottom Track

Sidescan Data Display windows Sonar information: Pitch, roll, heading, pressure and depth can be viewed. Graphical display of motion data from towfish Altitude window can highlight towfish height off seafloor. Alarm depth can be set in View Options (F9)

Sidescan Data Display windows All data is logged to the HSX file; this device selection is only for data displays Device Selection Allow user to specify which data to display for Sonar, Heading, Altitude..One example for use: While running a system with a MB backscatter and towed sidescan, this option allows you to specify the device to be shown in the waterfall.

Coverage Map  Show sidescan coverage with  Simple stick diagram (no matrix needed)  1x / 2x Coverage (grey scale swath image)  real-time sidescan mosaic.  Matrix is needed for the 1x,2x coverage or sidescan mosaic  The Matrix can be drawn in both HYPACK® SURVEY and HYSCAN coverage map. The Real time mosaic is saved as a HYPACK Matrix file. It is designed to show coverage during the survey. For a final GeoTif mosaic, use HYSCAN or GEOCODER Simple Stick coverage Real-time Sidescan Mosiac 1x 2 x coverage

Survey planning: 100% and 200% coverage 100% coverage: At 100 meter range scale, line spacing would be set for 160 meters. This provides a 20 meter off-track error while surveying. 200% coverage: This survey plan ensures that the bottom is covered twice by the Sidescan, covering the nadir region with the second line pass Swath width 200m Line spacing 160 meters Line spacing 80 meters Note the overall swath width is twice the range scale

Sidescan Data Playback To replay a sidescan file in HYSCAN, use option F8 ( File – Playback ). Select HSX, XTF or LOG file All HYSCAN windows can be opened. Targeting can be done in playback.

TARGETING IN SURVEY

Capture Image: Tool to save JPEG or GeoTiff 1.Select Camera Icon. 2.Click and drag around target to capture. 3.Image can be saved as Jpeg or GeoTiff format. Once saved, the Geo-referenced images (TIF) can be viewed in the HYPACK SHELL and Survey as a background file.

Capture and Measuring a contact: To mark a target, double click in the waterfall on the contact To measure a target, select the up-arrow icon and then double click on the contact. A target window will open to measure the feature and save to a file ( shown on the next slide ) Three points along the image are needed altitude (A), shadow length (L), total distance (R) Height of Contact (H) = L * A / R

In the Target Window:  Set Bar 1 to end of water column.  Set Bar 2 to target/shadow edge  Set Bar 3 to far end of shadow. Use the signal display to assist in finding the target and shadow (look for low or weak signal following the target) Height above bottom Mark and save target. Target will be displayed in HYPACK survey The target height may not be exact by two operators, due to the subjectiveness of shadow measurements Target Height Measurement Tool

Targeting in Action