The Underwater Domain Awareness (UDA) framework requires a nuanced approach towards evolving the policy and technology intervention along with the acoustic capacity and capability building.
Pune: The Underwater Domain Awareness (UDA) framework emerges as the most critical strategic construct in the 21st century, given ambitious announcements like the Security And Growth for All in the Region (SAGAR), the Indo-Pacific, Australia United Kingdom and United States (AUKUS) and more. All these declarations are maritime constructs and demand significant domain awareness to ensure effective management of the challenges and opportunities. The Maritime Domain Awareness (MDA) in its present form has remained a superficial formulation with no real impact on the ground requirements. The MDA has remained a security driven concept with limited participation from the other stakeholders and the concern for classified data is farfetched. The financial world provides far more access to all the stakeholders, and yet maintains data security to a considerable extent. The present level of technology allows significant safeguards. The second more important concern is the surface limitation of the MDA. The underwater component, which probably has the major component of resources and corresponding concerns is largely ignored. The UDA will require different technology and knowhow to build reasonable levels of situational awareness. The site-specific underwater characteristics particularly in the tropical littoral waters of the Indo-Pacific strategic space will require local field experimental Research and Development (R&D). Such field experimental R&D are highly resource intensive and need long term and sustained efforts. The democracies around the world cannot prioritise security budgets, given their socio-political and socio-economic realities. The Covid-19 pandemic has further accentuated the problem. The governance mechanisms are not able to comprehensively manage the safe, secure, sustainable growth model, and require a focused approach. The UDA framework, as proposed by the Maritime Research Centre (MRC), Pune encourages pooling of resources and synergizing of efforts across the stakeholders.
The ongoing efforts not just in India, but across the world, are highly fragmented across the stakeholders, policymakers and the associated entities. The underwater domain is highly specialized and cannot be clubbed with the other maritime activities on surface. The freshwater systems like the rivers, lakes, reservoirs and more can certainly be addressed jointly to bring more economy of scale. The social, political, economic and physical aspects need to be recognised and the strategy evolved accordingly. The UDA framework will require nuanced approach towards evolving the policy and technology intervention along with the acoustic capacity and capability building. These three are intertwined at multiple levels and will require clear understanding to build the comprehensive framework. It may be important to state that acoustics is the only signal that propagates effectively and efficiently underwater, so any attempt at UDA will require acoustic survey using sonars as the primary tool. The sonar, by definition, is any device that uses sound and its processing, as the primary means to derive information. Even underwater communication devices are part of a sonar systems. The sonar system has to provide detection and classification inputs for any application-specific decision making and actionable intervention.
Before we attempt to build a framework, it is important to understand the components of the UDA construct. Any domain awareness initiative will have a three-step approach: To See, To Understand and To Share. Each of these three steps have their unique challenges and opportunities from a strategic perspective. We build on these three steps to effectively understand the UDA framework.
“To See” translates into acoustic sensors and the platforms that will carry these sensors to the remotest corner of the undersea domain. Underwater acoustic sensors are highly specialized in terms of design and development, and very few entities globally are supplying such products. They also come under the restricted technology category and always require end-use certificate for imports. Any geopolitical and geostrategic developments impact the supply of such restricted products. The security applications never have the economy of scale and thus combined with geopolitical and geostrategic sensitivity, the costs become extremely prohibitive. The platforms conventionally have been the surface vessels with multiple limitations in terms of sensor range to the depths and also oversize limitations for customized missions. The Autonomous Underwater Vehicles (AUVs) are today emerging as the most agile and efficient means to deploy underwater sensors. AUVs are the epitome of Science & Technology (S&T) deployments on multiple fronts. Right from the design and development to application of specific deployment and mission specific reconfiguration, the AUVs provide unmatched options and effectiveness. Size, endurance, payload, maneuverability, agility and more, each of the factors needs to be optimized and multiple iterations are required, prior finalization.
The scalar acoustic sensors and the arrays of sensors with array signal processing have provided reasonable sensing capabilities. Most of the well-known acoustic sensors come from the Scandinavian countries and the United States. More recently, vector sensors with a strong backend processing support are emerging as the efficient sensing means for effective UDA. The Underwater Gliders with buoyancy engines are emerging as the most suited version of the AUVs. The underwater gliders are slow, so good for surveys and with very high endurance are ideal for long deployments. The low cost further adds to their advantage in deploying them in large numbers for maximum area coverage. The swarm deployments with cooperative processing algorithms can be used for much higher gains. The most critical advantage for UDA is, that in the absence of propellers, their own self noise is minimal.
“To Understand” becomes the most important step in this entire three-step formulation. The data acquired in the first stage comes with significant amount of noise and medium related distortions. The tropical littoral waters have their unique underwater channel characteristics and thus distort the signal at source (signal of interest) to a large extent. Their deployment also adds to the data corruption in multiple ways. Pre-processing requires a two-stage effort. The first is to filter the sensor and hardware related noise from the received signal and then in the second stage we attempt to clean the medium fluctuations. The normal filters with fixed characteristics are not good enough for such pre-processing requirements. The ambient noise estimation specific to the local site related characteristics is an important first step. Adaptive filtering techniques are effective only with high quality real time estimation of the ambient noise. The underwater channel modelling and field experimental data validation is a very critical step. Shallow Water Acoustic Measurements (SWAMs) have been undertaken in the South China Seas by the Americans, but the Indian Ocean Region (IOR) is yet to see such efforts. The ambient noise estimation and the underwater channel modelling are two essential UDA requirements to take forward any maritime governance effort.
Strategically, it may be noted that though sensors and the platforms need to be indigenized on priority, however the second phase of “to understand” needs much urgent efforts. The involvement of foreign players for data analysis, if at all is extremely dangerous as our data could be channelized to our adversaries and used against us. The sonar performance degradation in the tropical littoral waters is close to 70% and with enhanced ambient noise estimation and underwater channel modelling, the performance can be enhanced to at least twice of that. This enhancement of sonar performance for our own users, can be denied to our adversaries and thus will allow four times the strategic advantage over our adversaries.
Once the pre-processing is completed, we need to perform application-specific data analytics. The real-time processing requirement is inescapable and the Artificial Intelligence (AI) and Machine Learning (ML) based data analytics algorithms and also the High Performance Computing (HPC) infrastructure is needed. Resources and knowhow for field experimental validation is further necessary to comprehensively manage the entire UDA requirement. Digital Signal Processing (DSP) backed by AI & Robotics, is important for such an initiative.
“To Share” in real time is essential for initiating meaningful action. The data once processed and actionable inputs available, should be shared with all stakeholders and ground teams for immediate intervention. The entire communication network and the display mechanism has to be effectively structured for seamless flow of information with adequate security measures. The underwater communication using acoustic signals is still evolving, however, the Radio Frequency (RF) links, including satellite communication links and the associated networks and protocols, have matured significantly. Thus, the information should be brought to the surface of the water body and then the information can be passed through RF links. The speed of RF link is 3×108 m/s, whereas the speed of the acoustic link is 345 m/s.
The four stakeholders of the UDA framework, namely national security, blue economy, environment and disaster management, and science and technology providers have to come together and push for safe, secure, sustainable growth for all. The challenges and opportunities have to be managed comprehensively to ensure effective maritime governance. The proposed UDA framework also addresses the challenges and opportunities in the freshwater systems including water resource management, water quality management and more. A holistic approach towards to see, “to understand and to share” will make significant difference in ensuring good governance.
Dr (Cdr) Arnab Das is Founder & Director, Maritime Research Center (MRC), Pune.