Posted on 2 February 2017
A peer-reviewed technical communication was recently published in IEEE Journal of Oceanic Engineering presenting a review of the literature on software-defined underwater acoustic modems. The paper titled “Software-Defined Underwater Acoustic Modems: Historical Review and the NILUS Approach” by Dol. et. al presented the past and ongoing academic efforts, and industrial developments on the software defined underwater acoustic modem structures and functionalities.
The authors compare these software-defined modems based on the level of reprogrammability that is allowed for the user to apply the changes to physical layer, networking layer etc. In conclusion, the authors note that out of the many modems that exist today (shown in the figure), specifically seven of them marked in blue frames (in the figure) allow the physical and network layers to be fully reprogrammable. Subnero modem is one of such modems with the fully reprogrammable physical and network layer functionalities. We refer the interested reader to the paper which can be found at this link for more details.
Posted on 20 December 2016
The article interviews Dr. Mandar Chitre, one of the founders of Subnero, and talks about the applications of our underwater communication technology as well as some challenges in connecting the ocean to the internet.
Posted on 1 August 2015
With harmful algal blooms, eutrophication and emerging contaminants, monitoring of water bodies has become increasingly important. However water bodies cannot be modeled as isolated systems; many external factors such as urbanisation and other human activities affect them.
Proactive prediction to prevent events that can negatively impact our waters requires knowledge about various parameters. Traditionally water monitoring has been performed with static nodes that measure water quality at fixed points. These measurements are followed up with detailed water quality tests with collected water samples, as necessary. However water bodies are complex and their properties vary with space and time. With traditional methods, we only get very sparse temporal and spatial data. Scaling these methods has hitherto been impractical.
The Subnero Water Assessment Network (SWAN) addresses this issue by remotely monitoring water quality in water bodies using autonomous robots. The SWAN robots can operate in a fleet where they collaboratively sample a target area. The water quality data is available in real-time to operators of the SWAN. Operator personnel have the ability to then command the SWANs to refine the area of monitoring, focusing on areas of interest based on any unexpected data observed, for a more detailed analysis.
The autonomous nature of the solution allows for scaling to water bodies large & small. Moreover the modular nature of the SWAN allows the sensor payload on the SWAN to be easily swapped to focus on particular contaminants or general purpose monitoring or sampling. This makes the SWAN a powerful platform that is extensible to a variety of deployment needs. The visual appearance similar to an actual swan ensures that the monitoring system blends in with the environment.
Test bedding to date has shown that operators benefit from the autonomous nature of the platform, the real-time nature of the data collected and the ability to re-direct operations to focus on particular areas of concern. Efficiencies in terms of personnel deployment and operations has led to additional interest in expansion of operations.
Subnero offers the SWAN platform for deployments globally. Additional information is available here.
Posted on 9 June 2014
Wired UK covered Subnero in its June 2014 issue. The article focused on how Subnero’s technology could change the way we think about underwater communications, as applications could include wireless-enabled aquatic drones conducting real-time analysis, and augmented-reality goggles for divers.
Posted on 3 June 2014
Subnero (team Orca) took part in the Hydropreneur Programme and presented a product idea related to diver navigation and communication during the Singapore International Water Week (SIWW) 2014. The team won the ‘Most Disruptive Innovation Award’. The product idea focussed on using Subnero’s underwater communication technology to enable divers to communicate, navigate and share their dive log in real-time.
Posted on 22 March 2014
World water day is held annually on the 22nd of March.
Water day focuses on how important freshwater is. This also stresses the importance on keeping it clean and conserving it. However keeping it clean and safe requires a lot of work, especially in this day and age where eutrophication is a household term. We want to ensure that the aquatic ecosystem is healthy. This means monitoring a myriad different parameters. Although it is intuitive to assume water is well mixed and measuring in a single localized place is sufficient, this is not the case. Levels of dissolved oxygen, pH, salinity and other variables can differ spatially quite significantly. Monitoring many different locations also allows determination of where contaminants are introduced (if any) into the water body which can greatly help to mitigate unwarranted discharges into water bodies.
Subnero Water Assessment Network (SWAN) is our solution for water quality monitoring. Each node (shaped like a swan) is mobile and carries probes for monitoring. When a fleet of swans are tasked with monitoring a water body they can intelligently plan optimal routes to gather data from all over the water body. The data is uploaded to the cloud in real-time. This allows scientists to remotely analyze the water quality. They can then make informed decisions and preemptively identify potential problems.
Posted on 13 March 2014
Students from around the world undertake the challenge of building an underwater vehicle that has to perform a set of tasks autonomously. Tasks include following a path, dropping a ball in a bucket, bumping a flare and locating the exit which is demarcated with two acoustic pingers. All this has to be done without surfacing or touching the floor.
The competition also exposes students to a multitude of challenges faced in marine robotics. Some of the challenges are system engineering, automation and waterproofing to name a few.
There are teams from Canada, India, Malaysia and Singapore competing this year!
Viewing is open to public, so drop by to see AUVs swimming in a pool! And also come meet the Subnero volunteers helping with the organization of the challenge.
14th to 16th March 2014
Nanyang Technological University, Sports and Recreation Centre, 20 Nanyang Green, Singapore 637715.
Check out the SAUVC website for more details.
Posted on 24 February 2014
Standards are the reason why our phones and Wi-Fi routers of different brands can communicate seamlessly. In this case 802.11x being the accepted standard. However these standards haven’t been here since the birth of the wireless technology. It took a great deal of time to arrive at something most could agree upon. That time is here for underwater networks. There is a pressing need for a standard. Currently interoperability is limited and happens through gateways that will connect different set-ups, so nodes in one network will go through a ‘translator’ to be able to communicate with another network. However this is less than ideal for the long term and peer to peer offers a well-defined evolution as demonstrated by terrestrial wireless systems.
This need for a standard is extensively discussed in the article by Captain Edward H. Lundquist, Proceedings Magazine, February 2014.
To summarize some the key points of the article, The benefits of standardization are well known and widely accepted.
If a common communication system could be established in the underwater domain, the advantages would be immense Dr. Mandar Chitre
Standardisation isn’t all that far off as there is work underway. For instance, JANUS is NATO’s proposed standard for underwater communications.
The simple digital underwater signaling system can be used to contact underwater assets using a common format, announce the presence of an asset to reduce conflicts, and allow node discovery to enable a group of assets to organize themselves into an ad hoc network. It is the first digital underwater coding standard being developed to provide global interoperability in underwater communications CMRE research scientist Dr. John Potter
With standardization vendors need not worry about losing competitive edge.
It is necessary to have a basic framework that is standardized while letting technology providers innovate and provide differentiated products that fit within the framework, this would ensure that technology vendors do not lose their competitive edge by agreeing to standards, but instead create a larger market where their products can easily be integrated with other vendors’ products to create systems beyond what is possible today. Dr. Mandar Chitre
Posted on 26 October 2013
The Acoustic Research Laboratory (ARL) and Subnero are proud to announce the public availability of UnetStack v1.1.1: The flexible network stack for underwater communications!
UnetStack v1.1.1 is now available for download
The intent of UnetStack is to provide a framework for promoting community collaboration in the underwater networks arena. Key elements include:
- Agent-based network stack
- Customizable, extensible and scriptable
- Cross-layer cooperation
- Run same code in simulator and modem
- Interactive shell and remote access
- Supports multiple acoustic and RF links
- Easy to learn and use!
The extensible underwater stack implementation (UnetStack) & related documentation, and a simulator for underwater networks are available for download at www.unetstack.net. An active discussion board is also available for troubleshooting support and general underwater networking-related discussions.
UnetStack-conformant software-defined modem now available
A modem implementation of UnetStack is now available to unleash the full abilities of the stack in field deployments. The Subnero Underwater Modem (formerly known as the UNET-2 modem) is designed with flexibility and sensibility as basic design objectives, addressing commonly faced constraints with technologies available thus far.
Sea trials and deployment experience have repeatedly proven outstanding performance, including in extremely challenging underwater acoustic conditions. The modem is provided by Subnero, further information on Subnero’s website
Posted on 1 September 2013
Commonly cited challenges in underwater networks include low bandwidth, long propagation delay, half-duplex nature of the links, high packet loss, and time-variability. To deploy successful networks in the face of such challenges, cross-layer information sharing, low-bandwidth design and accurate transmission/reception timing can be critical. Traditional layered network stacks provide good separation of concern, but result in sub-optimal protocols for underwater networks.
UnetStack, a Java/Groovy-based software-defined underwater network stack, takes a different approach. It consists of a collection of software agents that provide well-defined services to allow good separation of concern while allowing information to be shared, services to be provided, and behaviors to be negotiated between different agents. The resulting solution is flexible and allows software-defined underwater networks to be rapidly designed, simulated, tested and deployed.
UnetStack has been developed over several years, and tested through numerous underwater network experiments at sea. A community version of UnetStack has recently been made freely available for academic and research use. This version allows rapid development and simulation of underwater networking protocols. Once protocols are developed and testing using this framework, they can be deployed without the need for porting in any UnetStack-compliant underwater modem for field use.
Posted on 9 March 2013
The domain of underwater communications is at a tipping point, with the level of interest in underwater technology seeing substantial growth in recent years.
While nodes in water are by no means new, the ability to connect these aquatic denizens - submarines, autonomous underwater vehicles (AUVs), sensing elements etc. via a network is now being recognized as a key planning element by defense & homeland security agencies, water utilities- and commercial entities in a variety of industries that deal with in-water solutions.
In its Technology Quarterly issue (March 9th, 2013), the Economist magazine ran an article titled “Captain Nemo goes online”, further acknowledging the growth in the underwater networking space. One of Subnero’s founders, Dr. Mandar Chitre is cited in the article, acknowledged for technological innovation that allows underwater communication to occur over large distances in extremely challenging conditions.