Industry News

New Class of Underwater Acoustic Modems

Subnero modems are at the forefront of the underwater wireless communication technology.

In addition to providing unparalleled communication and networking performance, they also provide the user with the ability to transmit and record arbitrary waveforms. Being software-defined, these devices provide the flexibility to you, the user, to develop or extend the capabilities using your own techniques. We, at Subnero are constantly working to bring you new features to help you realize your vision of underwater communications and networking.

Now, imagine being able to use our modems to do things that were not possible previously, with a conventional acoustic modem. For example, let’s say you have a communication link, that stops working beyond a certain range. You upgrade your modem and you can extend your communication range beyond what was previously possible.

Or, say you want to monitor and record the underwater soundscape, but also send events of interest back to a control station in real-time, or allow control of the recording device from the surface. It would be nice to have a single device that can allow recording using multiple synchronized receiving channels, but also be able to communicate with that device directly, without the need to attach an external modem.

What if you have a single device that can do all of these functions in real-time? We are very excited to launch a new class of underwater acoustic modems, called the Subnero multi-channel modems. The multi-channel modems combine our silver edition M25M series modems, with a multi-channel acoustic recorder, thereby providing an acoustic modem with multiple synchronous receiving channels, without a significant change of the form factor. Configurable with up to 4 additional synchronous receiving channels, each channel can have a sampling rate of 128 or 256 kilo samples per second.

Out-of-the-box, you can use the multi-channel modems as a normal modem or a standalone acoustic recorder or both at the same time. The data collected from the additional receiving channels can be saved to the modem’s internal storage to be downloaded later. The recordings can be scheduled before deployment or triggered remotely using specific signals thereby making the multi-channel modems, ideal candidates for applications such as rapid environment assessment.

These devices use spatial diversity combining techniques to decode transmissions from remote modems, in real-time. This increases the effective communication range by acting as a spatial diversity receiver.

In addition to the extra receiving channels, the multi-channel modems are also equipped with sensors such as GPS, compass and a depth sensor, for underwater positioning and tracking applications. By combining techniques such as time or phase difference of arrival with the data from these sensors, three-dimensional positioning and tracking is also available with the multi-channel modems.

Some of these features will be available as a software upgrade in the form of UnetStack premium agents.

For power users, the full potential of the device can be harnessed through the customizability of UnetStack. You can get direct access to raw data from all the channels in real-time, through UnetStack APIs. The out-of-the-box length of the hydrophone cables is 10 m from the housing, which allow you to decide the placement of these channels depending on your application. With such flexibility, a user can develop their own array processing or spatial diversity combining techniques or positioning applications with the help of various developer tools provided by UnetStack. With native support for scientific computing languages such as Julia, or UnetStack gateway support with Python, these devices reduce the time to deployment of your algorithms, dramatically. In short, the kinds of applications you can develop using our multi-channel modem platform is only limited by your imagination.

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