Technical Description - Bathyswath-XL



Bathyswath-XL is a 40 kHz, 6000-metre pressure-rated system. It is provided as an OEM kit of parts for integration into deep-operated platforms, for full-ocean-depth survey work.


  • Applications for Bathyswath-XL include:
  • Operation from very deep-towed platforms and/or scientific research.
  • Operation on large autonomous underwater vehicles (AUV).
  • Surface vessels; with the transducer arrays fitted to the hull of the vessel.


Bathyswath-XL is a wide-swath bathymetry and sidescan imaging system.

The basic sonar system consists of the following components:

  • Transducer Bathyswath Electronics Modules (TEMs); these contain the main system electronics, and connect the sonar transducers to the data acquisition system. For use on deep-towed or autonomous platforms, these components can be provided in a 6000m-rated pressure vessel.
  • Power amplifiers: these drives the sonar transmit pulses. The power amplifiers are usually provided in a separate housing.
  • Sonar transducer arrays: one facing port, and one facing starboard. These are rated to 6000m pressure depth.
  • Bathyswath software suite; this supports real-time data acquisition, post-processing, and interfaces to most third-party software suites.


Bathyswath-XL Transducer array

A Bathyswath-XL survey system includes two such arrays, facing port and starboard.

Technical support and training to assist the purchaser to integrate and operate the system are offered at additional cost.


Bathyswath-XL can be mounted on:

  • Surface vessels; with the transducer arrays fitted to the hull of the vessel.
  • Towed platforms and ROVs; operating down to 6000m depth.
  • Autonomous underwater vehicles (AUVs).

Typical Bathyswath-XL configuration block diagram for a towed vehicle.

Items in grey are not part of the base sonar system (these can be provided on request)

In addition to the standard Bathyswath software, Bathyswath-XL provides specific software functionality for deep-ocean work.

Pilot Displays

With deep-operated vehicles, the vehicle Pilot has responsibility for the safety and operation of the vehicle and its systems. Software functions that support this role include:

  • Monitoring vehicle altitude: this can be done using the bathymetry cross-profile display, and an altitude figure written to a text window. The text window will also be capable of displaying a rate-of-climb (or descent) figure.
  • Monitoring Bathyswath performance: this can be monitored using the standard bathymetric views (waterfalls, cross profiles, etc.), and by specific diagnostic windows (amplitude-range display, angle & phase-range display, text views).
  • Tuning the sonar parameters: this is done in the Sonar settings dialog.
  • Monitoring survey coverage, and modifying the track and/or sonar settings as appropriate: this is done using the Coverage window.

The pilot is able to select from all of the displays and controls listed in the previous sections.

  • Textual parameter outputs provided that are applicable to the pilot are as follows:
  • Vehicle attitude: roll, pitch and heading.
  • Vehicle position (incl. source of position, e.g. IUSBL, calculated from cable out, read from file, fixed value).
  • Vehicle depth and Vehicle rate of climb (and descent).
  • Vehicle altitude (calculated from a mean of swath profile depths close to nadir).
  • Ship Position and Cable Out.
  • System status, including error conditions.

Scientific Displays

For ocean science applications, the end-users of the data from Bathyswath-XL would use views such as:

  • Standard bathymetric views (waterfalls, cross profiles, etc.) and text views.
  • Gridded data 3D and 2D views; these are created by “dropping in” data files as soon as they are available from the main Swath Processor application.
  • Outputs to third-party tools.

A second SWATH display can be implemented by use of the existing TCP/IP data interface in the Swath Processor application to drive a second instance of the Swath software on another PC at the scientists’ position. This allows the scientists to configure and save their own set of view windows, but not to control the parameters of the Bathyswath sonar. Information and guidance on the use of the SWATH software for a second display and an additional software licence will be provided for this purpose.

Storing and Retrieving Display Layouts

The layout and configuration of display windows in the Bathyswath software can be saved to, and retrieved from, files on disk. Therefore, individual operators (including the Pilot and Scientist roles) may configure the display console to suit their needs.