Synchronizing towed body media with echograms

Echoview Synchronize, Synchronize To Point or Auto-synchronization allow echogram and Media window synchronization.

Required data

Note:

Synchronizing an echogram and towed media data

  1. Create a new EV file.
  2. Add echosounder files, image/video files and a length CSV file to separate fileset tabs.
  3. On the Dataflow window, select the Media variable corresponding to the added image/video file, then right-click and select Variable Properties.
  4. Select the Media Position page and configure the settings.
  5. Select OK.
  6. Double-click to display an echogram.
  7. Double-click to display a Media window.
  8. Use right-click menu, Synchronize or Synchronize to Point or an Auto-synchronization group to synchronize an echogram with the Media window.

Towed Body Time Offset and towed body Media Position calculations

With suitable associated data (see Required data above), Echoview can determine the offset time required for synchronizing the transducer pings and media recorded from a towed body. Offset times for synchronization are derived from towed body and Platform geometries, right-angle triangle relationships and GPS fixes. See Assumptions and behavior.

Figure 1: The geometric scheme used in distance and time calculations.

Assumptions and behavior

Echoview considers the platform and towed body geometries and calculates the (right-angle) distance from the tow point (TP) to the towed body. The time offset is relative to the ping data (i.e. the platform's GPS data which logs the time and position). For each ping, Echoview iterates through GPS fixes with respect to the horizontal distance between the platform and towed body. Echoview then interpolates between fixes for final distance matching and time estimation.

See also

About Media data
About length data
Line CSV data
Towed body time offset virtual line
About transducer geometry