It’s the second time the Senate Judiciary Committee declined to pass a version of the bill.

EFF calls on the Kuwaiti government to immediately release journalist Ahmed Shihab-Eldin. An award-winning journalist and television host who worked for Al Jazeera for many years, Shihab-Eldin—a dual American-Kuwaiti citizen—was arrested in Kuwait on March 3 while visiting family. The Committee to Protect Journalists (CPJ) reported yesterday that it is believed he has been charged with spreading false information, harming national security, and misusing his mobile phone.

According to the Guardian, Shihab-Eldin published footage of a U.S. Air Force F-15 E Strike Eagle crash, and posted to his Substack about the incident, noting that video circulating online showed local residents assisting the crash survivors. 

Kuwait is one of several countries that has recently cracked down on reporting amidst the ongoing war. Kuwait’s Ministry of Interior posted on X on March 3—the same day Shihab-Eldin was arrested—warning people in the country “not to photograph or publish any clips or information related to missiles or relevant locations.” Earlier this month, the UN Office of the High Commissioner for Human Rights (OHCHR) highlighted a new decree in Kuwait banning the circulation of reports that seek to “undermine the prestige of the military” or erode public trust in it. 

As reported by local media, the decree states that “those who intentionally publish statements or news or circulate false reports and rumors about military authorities resulting in weakening the trust in them and their morale, in addition to undermining their prestige, are punishable by three to 10 years in jail and a fine between KD 5,000 and 10,000.” The decree also imposes a penalty ranging from seven years to life imprisonment for “authorized people who cause financial loss or damage to the military authorities while carrying out a transaction, operation, project or case or obtaining any profit from such deals.”

In contrast to neighboring Gulf states, Kuwait has historically allowed the press to operate with relative freedom, and even introduced a law in 2020 protecting the right to access information. In practice, however, the government exercises considerable control over the media. Furthermore, there are several laws, including cybercrime legislation introduced in 2016, that restrict freedom of expression.

EFF is deeply concerned that Ahmed has not been seen nor heard from in nearly six weeks. We call on the government of Kuwait to immediately release Ahmed Shihab-Eldin. 

This is the fourth installment of a blog series reflecting on the global digital legacy of the 2011 Arab uprisings. You can read the rest of the series here.

Iran’s internet has been intermittently disrupted for months. After years of bombardment, Gaza’s telecommunications infrastructure remains fragile. In India, recurring shutdowns and throttling have become a routine response to protests and unrest, cutting millions off from news, work, and basic services. Across dozens of other countries, governments increasingly treat connectivity itself as something that can be weaponized—cut, slowed, or selectively restored to shape what people can see, say, and share. In 2024 alone, authorities imposed 304 internet shutdowns across 54 countries—the highest number ever recorded.

In 2011, when protesters in Tunisia, Egypt, and beyond used social media to broadcast their uprisings to the world, many observers heralded a new era of networked freedom. Governments, however, responded quickly by developing and refining systems of control that have only grown more sophisticated over time. Today’s landscape of regulation, blackouts, and degraded networks reflects that trajectory, as early experiments in censorship and disruption have hardened into a durable system of control—what began as an emergency measure has become a normalized infrastructure of control.

A Brief History of Internet Shutdowns

Egypt’s 2011 internet shutdown wasn’t the first. Although the government’s heavy-handed response after just two days of protests caught the world’s attention, Guinea, Nepal, Myanmar, and a handful of other countries had previously enacted shutdowns. But Egypt marked a turning point. In the years that followed, shutdowns increased sharply worldwide, suggesting that governments had taken note—adopting network disruptions as a tactic for suppressing dissent and limiting the flow of information within and beyond their borders.

On January 28, 2011, at 12:34 a.m. local time, five of Egypt’s internet service providers (ISPs) shut down their networks. At least one provider—Noor, which also hosted the Egyptian stock exchange—remained online, leaving only about 7% of the country connected. 

In the aftermath of President Hosni Mubarak’s resignation, rights groups sought to understand how such a sweeping shutdown had been possible—and how future incidents might be prevented. There was no centralized “kill switch.” Instead, authorities leveraged the country’s highly consolidated telecommunications sector, which all operate by government license. With only a handful of ISPs, a small number of directives was enough to bring most of the network offline.

In the years following Egypt’s 2011 shutdown, telecommunications companies—many of which had been directly implicated in enabling state-ordered disruptions—began to organize around a shared set of human rights challenges. Beginning that same year, a group of operators and vendors quietly convened to examine how the UN Guiding Principles on Business and Human Rights applied to their sector, particularly in contexts where government demands could translate into sweeping restrictions on access. By 2013, this effort had formalized into the Telecommunications Industry Dialogue, bringing together major global firms to develop common principles on freedom of expression and privacy and, through a partnership with the Global Network Initiative, engage more directly with civil society. The initiative reflected a growing recognition that telecom companies—unlike platforms—operate at a critical chokepoint in the network. But it also underscored the limits of voluntary approaches: while the Dialogue helped establish shared norms, it did little to constrain the legal and political pressures that continue to drive shutdowns—or to prevent companies from complying with them.

From Emergency Measure to Legal Authority

If the early aughts were defined by improvised shutdowns, the years since have seen governments formalize their power to control networks. What was once exceptional is now often embedded in law.

In India, the 2017 Temporary Suspension of Telecom Services Rules—issued under the Telegraph Act—provided a clear legal pathway for cutting connectivity. The Telecommunications Act, 2023, further entrenched the government’s ability to enact shutdowns, granting the central and state governments, or “authorised officers” the power to suspend telecommunications services in the interest of public safety or sovereignty, or during emergencies. The government has used these measures repeatedly, particularly in Jammu and Kashmir. India’s Software Freedom Law Centre’s Shutdown Tracker shows India as instigating more than 900 shutdowns, 447 of which were in Jammu and Kashmir.

In Kazakhstan, shutdowns have also become common. Over the years, the government has passed legislation that allows state agencies to shut down the internet. The 2012 law on national security enabled the government to disrupt communications channels during anti-terrorist operations and to contain riots. In 2014 and 2016, laws were further amended to expand the number of actors able to shut down the internet without a court decision, and a government decree in 2018 enabled shutdowns in the event of a “social emergency.” 

Elsewhere, governments have built or expanded legal and technical frameworks that enable similar control over information flows. Ethiopia’s state-dominated telecom sector has facilitated sweeping shutdowns during periods of conflict, including the war in Tigray, where the internet was disconnected for more than two years. In Iran, authorities have developed regulatory and infrastructural capacity to isolate domestic networks from the global internet, allowing them to restrict external visibility while maintaining limited internal connectivity. This year alone, Iranians have spent one third of the year offline. And amidst the ongoing war, Iranian officials have made it clear that the internet is a privilege for those who toe the government’s official line.

Even where laws do not explicitly authorize shutdowns, broadly worded provisions around national security or public order are routinely used to justify them. The result is a growing legal architecture that treats network disruptions not as extraordinary measures, but as standard tools for managing populations.

When that authority is exercised over a population beyond a state’s own citizens, the consequences can be even more severe. Israel’s Ministry of Communications controls the flow of communications in and out of Palestine and has used that power to shut down internet access during periods of conflict. Over the past two and a half years, Gaza has experienced repeated outages, and experts now estimate that roughly 75% of its telecommunications infrastructure has been damaged—leaving essential services severely disrupted.

Elections and the Expansion of Control

Historically, most blackouts have occurred during moments of intense political tension. But authorities are increasingly using them as a tool to preempt dissent.

In 2024, as more than half the world’s population headed to the polls, shutdowns followed. That year alone, authorities imposed 304 internet shutdowns across 54 countries—the highest number ever recorded, surpassing the previous record set just a year earlier. The geographic spread also widened significantly, with shutdowns affecting more countries than ever before. The Comoros imposed a shutdown for the first time, while other countries, such as Mauritius, instituted broad bans on social media platforms during elections.

At least 24 countries holding elections in 2024 had a prior history of shutdowns, putting billions of people at risk of disruptions during critical democratic moments.

What stands out is not just the scale, but the normalization. Notably, the number of shutdowns in 2025 broke the record set the year prior. Whereas network disruptions were once a rare occurrence, they are now a routine measure, increasingly treated by authorities as a standard response to periods of heightened political sensitivity. 

Civil Society Fights Back

Governments use all sorts of justifications—national security, curbing the spread of disinformation, and even preventing students from cheating on exams—for internet shutdowns. But civil society is watching, and documenting, network disruptions and their impact on citizens.

In 2016, as shutdowns became an increasingly common tool of state control, Access Now launched the #KeepItOn campaign to coordinate global advocacy against network disruptions. The campaign includes a coalition composed of 345 advocacy groups (including EFF), research centers, detection networks, and others who work together to report on, and fight back against, internet shutdowns. Anyone can get involved by signing on to campaign action alerts, sharing their story, or reporting a shutdown in their jurisdiction.

Ending this harmful practice remains the goal. In 2016, the UN passed a landmark resolution supporting human rights online and condemning internet shutdowns, and UN agencies have continued to warn against the practice. But the fight to change government practices remains an uphill battle, leading civil society—and even companies—to get creative. 

During repeated shutdowns in Gaza, grassroots efforts mobilised to distribute eSIMs so Palestinians could stay connected. In 2024, EFF recognized Connecting Humanity, a Cairo-based non-profit providing eSIM access in Gaza, with its annual award for its vital work. Satellite internet such as Starlink has been supplied to people in Ukraine and Iran, though it, too, is not immune to state control. Alongside these efforts, civil society continues to share practical guidance on circumventing shutdowns and maintaining access to information.

EFF’s mission is to ensure that technology supports freedom, justice, and innovation for all people of the world—and we’ll continue to fight back against internet shutdowns wherever they occur.

This is the fourth installment of a blog series reflecting on the global digital legacy of the 2011 Arab uprisings. Read the rest of the series here.

This article on the walls of Constantinople is fascinating.

The system comprised four defensive lines arranged in formidable layers:

• The brick-lined ditch, divided by bulkheads and often flooded, 15­-20 meters wide and up to 7 meters deep.
• A low breastwork, about 2 meters high, enabling defenders to fire freely from behind.
• The outer wall, 8 meters tall and 2.8 meters thick, with 82 projecting towers.
• The main wall—a towering 12 meters high and 5 meters thick—with 96 massive towers offset from those of the outer wall for maximum coverage.

...

Climate change and the energy transition are driving a wave of state laws overriding local governments, with both parties driving their preferred policies.

Municipalities in the U.S. territory have asked a federal appeals court to revive their first-in-the-nation racketeering case against the oil and gas industry.

The Health Action Alliance launched its Extreme Weather + Work initiative Wednesday with 11 member companies.

The revisions highlight a growing divide among Democrats over gas prices and climate policy.

EPA's endangerment finding was an unlawful use of legislative authority reserved to Congress, the senators argue in a court brief.

The chief sustainability officer said the company may recalibrate its approach to reducing its carbon footprint.

The Atlanta-based carrier deleted its pledge to use sustainable aviation fuel for 10 percent of its jet fuel by 2030.

A “green divide” is growing between richer and poorer Europeans, a new study finds.

A 2025 report by aid group Mercy Corps warned that Kabul faces "an unprecedented humanitarian disaster within the coming decade."

Nature Climate Change, Published online: 15 April 2026; doi:10.1038/s41558-026-02617-w

Optimal climate change mitigation pathways have historically focused on achieving emissions reductions while ensuring cost efficiency. However, the broader impacts of climate action are also important for policymakers and stakeholders. We developed a method that enables mitigation pathways to be defined based on their impact on multiple United Nations Sustainable Development Goals (SDGs).

Nature Climate Change, Published online: 15 April 2026; doi:10.1038/s41558-026-02599-9

This work shows that increased eddies accelerate surface warming in the Agulhas Current while also boosting hidden upwelling that cools the current, and adjacent shelf seas, at depth. Similar trends are expected for all subtropical western boundary currents, even if volume transports remain steady.

A special class of sensors leverages quantum properties to measure tiny signals at levels that would be impossible using classical sensors alone. Such quantum sensors are currently being used to study the inner workings of cells and the outer depths of our universe.

Particularly promising are solid-state quantum sensors, which can operate at room temperature. Unfortunately, most solid-state quantum sensors today only measure one physical quantity at a time — such as the magnetic field, temperature, or strain in a material. Trying to measure both the magnetic field and temperature of a material at the same time causes their signals to get mixed up and measurements to become unreliable.

Now, MIT researchers have created a way to simultaneously measure multiple physical quantities with a solid-state quantum sensor. They achieved this by exploiting entanglement, where particles become correlated into a single quantum state. In a new paper, the team demonstrated its approach in a commonly used quantum sensor at room temperature, measuring the amplitude, frequency, and phase of a microwave field in a single measurement. They also showed the approach works better than sequentially measuring each property or using traditional sensors.

The researchers say the approach could enable quantum sensors that can deepen our understanding of the behavior of atoms and electrons inside materials and living systems like cancer cells.

“Quantum multiparameter estimation has been mostly theoretical to date,” says co-lead author of the paper Takuya Isogawa, a graduate student in nuclear science and engineering. “There have been very few experiments that actually demonstrate it, and that work focused on photons. We wanted to demonstrate multiparameter estimation in a more application-oriented setup: a solid-state quantum sensor in use today.”

Joining Isogawa on the paper are co-lead authors Guoqing Wang PhD ’23 and MIT PhD candidate Boning Li. The other authors on the paper are former MIT visiting students Zhiyao Hu and Ayumi Kanamoto; University of Tokyo PhD candidate Shunsuke Nishimura; Chinese University of Hong Kong Professor Haidong Yuan; and Paola Cappellaro, MIT’s Ford Professor of Engineering, a professor of nuclear science and engineering and of physics, and a member of the Research Laboratory of Electronics.

Quantum effects for measurement

Quantum sensors exploit quantum effects like entanglement, spin states, and superposition to measure changes in magnetic fields, electric fields, gravity, acceleration, and more. As such, they can be used to measure the activity of single molecules in ways that are useful for understanding biology and space, like tracking the activity of metabolites or enzymes inside cells.

One particularly useful sensor in biology leverages what’s known as nitrogen-vacancy (NV) centers in diamonds, a defect where a carbon atom in the diamond’s crystal lattice is replaced by a nitrogen atom, and a neighboring lattice site is missing, or vacant. The defect hosts an electronic spin whose transition frequencies can be read out optically. The NV center’s spin state is extremely sensitive to external effects, such as magnetic fields and temperature, which can shift the spin state in ways that can be measured at extremely high resolution.

Unfortunately, different external effects change the energy resonances of the spin in similar ways, making it difficult to measure multiple effects at once. The result is that most solid-state quantum sensor applications measure a single physical quantity at one time.

“If you can only measure one quantity at a time, you have to repeat experiments to measure quantities one by one,” Isogawa says. “That takes more time, which means less sensitivity. It also makes experiments more susceptible to errors.”

For their experiment, the researchers used NV centers inside of a 5-square-millimeter diamond. They pointed a laser into the diamond and studied its fluorescence to make their measurements, a common approach for such sensors. To study the electronic spin of the NV center, they used a microwave antenna. To study the spin of the nitrogen atom they used a radio frequency field.

“We used those two spins as two qubits,” Isogawa says, referring to the building blocks of quantum computing systems. “If you have only one qubit, you can only measure one outcome: basically, 0 or 1. It’s the probability that it spins up or down. Think of it like a coin toss, with the probability of getting heads or tails. With two qubits, we increased the parameters that we could extract.”

The system worked because the spins of the sensor qubit and auxiliary qubit were entangled, a quantum property where the state of one particle is dependent on another. With one qubit, you get a binary outcome. With two, you get four possible outcomes with a total of three possible parameters.

The two qubits allowed researchers to measure those three quantities simultaneously using a technique known as the Bell state measurement.

Other researchers had used the Bell state measurement at extremely low temperatures before, but the MIT researchers developed a new technique to perform the measurement at room temperature. That technique was first proposed by Wang, who was previously a graduate student in Professor Cappellaro’s lab.

The researchers used the approach to simultaneously measure the amplitude, detuning, and phase of a microwave magnetic field. The researchers also say the approach could be used to measure electric fields, temperature, pressure, and strain.

“Measuring these parameters simultaneously can help us explore spin waves in materials, which is an important topic in condensed matter physics,” Isogawa says. “NV center sensors have extremely high spatial resolution and versatility. It can measure a lot of different physical quantities.”

More practical quantum sensing

The researchers say this work is an important step toward using solid-state quantum sensors to more fully characterize systems in biomedical research and materials characterization. That’s because multiparameter estimation had never been achieved in realistic settings or in widely used quantum sensors.

“What makes the NV center quantum sensors so special is they can operate at room temperature,” Isogawa says. “It’s very suitable for biological measurements or condensed matter physics experiments.”

Although the researchers say their sensor didn’t measure each quantity at the highest possible precision, in future work they plan to explore if their approach can achieve higher precision for each parameter.

They also plan to explore how their approach works to characterize heterogenous materials.

“In an extremely uniform environment, you could use many different classical and quantum sensors and measure each physical quantity at the same time,” Isogawa says. “But if the physical quantities change at different locations, you need high spatial sensors, and you need a sensor that can measure multiple physical quantities. This approach has major advantages in such situations.”

The work was supported, in part, by the U.S. National Science Foundation, the National Research Foundation of Korea, and the Research Grants Council of Hong Kong.

In September 2024, Amandla Thomas-Johnson was a Ph.D. candidate studying in the U.S. on a student visa when he briefly attended a pro-Palestinian protest. In April 2025, Immigration and Customs Enforcement (ICE) sent Google an administrative subpoena requesting his data. The next month, Google gave Thomas-Johnson's information to ICE without giving him the chance to challenge the subpoena, breaking a nearly decade-long promise to notify users before handing their data to law enforcement. 

Today, the Electronic Frontier Foundation sent complaints to the California and New York Attorneys General asking them to investigate Google for deceptive trade practices for breaking that promise. You can read about the complaints here. Below is Thomas-Johnson's account of his ordeal. 

Out of touch but not out of reach 

I thought my ordeal with U.S. immigration authorities was over a year ago, when I left the country, crossing into Canada at Niagara Falls.  

By that point, the Trump administration had effectively turned federal power against international students like me. After I attended a pro-Palestine protest at Cornell University—for all of five minutes—the administration’s rhetoric about cracking down on students protesting what we saw as genocide forced me into hiding for three months. Federal agents came to my home looking for me. A friend was detained at an airport in Tampa and interrogated about my whereabouts. 

I’m currently a Ph.D. student. Before that, I was a reporter. I’m a dual British and Trinadad and Tobago citizen. I have not been accused of any crime. 

I believed that once I left U.S. territory, I had also left the reach of its authorities. I was wrong. 

The email

Weeks later, in Geneva, Switzerland, I received what looked like a routine email from Google. It informed me that the company had already handed over my account data to the Department of Homeland Security. 

At first, I wasn’t alarmed. I had seen something similar before. An associate of mine, Momodou Taal, had received advance notice from Google and Facebook that his data had been requested. He was given advanced notice of the subpoenas, and law enforcement eventually withdrew them before the companies turned over his data. 

Google had already disclosed my data without telling me.

I assumed I would be given the same opportunity. But the language in my email was different. It was final: “Google has received and responded to legal process from a law enforcement authority compelling the release of information related to your Google Account.” 

Google had already disclosed my data without telling me. There was no opportunity to contest it. 

Google’s broken promise

To be clear, this should not have happened this way. Google promises that it will notify users before their data is handed over in response to legal processes, including administrative subpoenas. That notice is meant to provide a chance to challenge the request. In my case, that safeguard was bypassed. My data was handed over without warning—at the request of an administration targeting students engaged in protected political speech. 

Months later, my lawyer at the Electronic Frontier Foundation obtained the subpoena itself. On paper, the request focused largely on subscriber information: IP addresses, physical address, other identifiers, and session times and durations. 

But taken together, these fragments form something far more powerful—a detailed surveillance profile. IP logs can be used to approximate location. Physical addresses show where you sleep. Session times would show when you were communicating with friends or family. Even without message content, the picture that emerges is intimate and invasive.  

State power meets private data

What this experience has made clear is that anyone can be targeted by law enforcement. And with their massive stores of data, technology companies can facilitate those arbitrary investigations. Together, they can combine state power, corporate data, and algorithmic inference in ways that are difficult to see—and even harder to challenge. 

The consequences of what happened to me are not abstract. I left the United States. But I do not feel that I have left its reach. Being investigated by the federal government is intimidating. Questions run through your head. Am I now a marked individual? Will I face heightened scrutiny if I continue my reporting? Can I travel safely to see family in the Caribbean? 

Who, exactly, can I hold accountable?

This is a current list of where and when I am scheduled to speak:

• I’m speaking at DemocracyXChange 2026 in Toronto, Ontario, Canada, on April 18, 2026.
• I’m speaking at the SANS AI Cybersecurity Summit 2026 in Arlington, Virginia, USA, at 9:40 AM ET on April 20, 2026.
• I’m speaking at the Nemertes [Next] Virtual Conference Spring 2026, a virtual event, on April 29, 2026.
• I’m speaking at RightsCon 2026 in Lusaka, Zambia, on May 6 and 7, 2026.
• I’m giving a keynote address and participating in a panel discussion at an ICTLuxembourg event called “...

Google's Failure to Warn Users About Law Enforcement Demands for Data Is Deceptive

SAN FRANCISCO – The Electronic Frontier Foundation sent complaints today to the attorneys general of California and New York urging them to investigate Google for deceptive trade practices, related to the company's broken promise to give users prior notice before disclosing their information to law enforcement. 

The letters were sent on behalf of Amandla Thomas-Johnson, whose information was disclosed to U.S. Immigration and Customs Enforcement (ICE) without prior notice from Google. 

For nearly a decade, Google has promised billions of users that it will notify them before disclosing their personal data to law enforcement. Many times, the company has done just that. But through a hidden and systematic practice, Google has likely violated that promise numerous times over the years. This was the case for Thomas-Johnson, a Ph.D. candidate who was targeted by ICE after briefly attending a protest, effectively preventing him from contesting an invalid subpoena for his data. 

"Google should answer the question: How many other times has it broken its promise to users?” said EFF Senior Staff Attorney F. Mario Trujillo. "Advance notice is especially important now, when agencies like ICE are unconstitutionally targeting users for First Amendment-protected activity. State attorneys general should investigate Google for this deception." 

On Google’s Privacy & Terms page, it promises its users that “When we receive a request from a government agency, we send an email to the user account before disclosing information.” This promise ensures that users can protect their own privacy and decide to challenge overbroad or illegal demands on their own behalf.   

But on May 8, 2025, Google complied with an administrative subpoena from ICE seeking Thomas-Johnson’s subscriber information, including his name, address, IP address, and other personal identifiers. Later that same day, the company sent Thomas-Johnson a message telling him it had already complied with the subpoena, which he would have successfully challenged had he been given advance notice. Google received the subpoena in April and had more than a month to alert Thomas-Johnson. 

Communication between EFF and Google later revealed that this is a systematic issue, not an isolated one. When Google does not fulfill a subpoena within a government-provided artificial deadline, the company's outside counsel explained, Google will sometimes comply with the request and provide notice to a user on the same day. The company calls this practice “simultaneous notice.” 

"What this experience has made clear is that anyone can be targeted by law enforcement," said Thomas-Johnson. "And with their massive stores of data, technology companies can facilitate those arbitrary investigations. Who, exactly, can I hold accountable?" 

Google must commit to ending this deception and pay for its past mistakes. The attorneys general of California and New York are empowered to stop deceptive business practices and seek financial restitution stemming from those practices. As EFF writes in its complaints, they should investigate, hold Google to its public promise to give users advanced notice of law enforcement demands, and take appropriate action if necessary. 
 
For the complaints:
https://www.eff.org/document/eff-letter-re-google-notice-california 
https://www.eff.org/document/eff-letter-re-google-notice-new-york 
https://www.eff.org/document/eff-letter-re-google-notice-exhibits
 
For Thomas-Johnson's account of his ordeal: https://www.eff.org/deeplinks/2026/04/google-broke-its-promise-me-now-ice-has-my-data 

For more information on lawless DHS subpoenas: https://www.eff.org/deeplinks/2026/02/open-letter-tech-companies-protect-your-users-lawless-dhs-subpoenas 

Contact: press@eff.org 

Tags: privacyfree speechanonymityDHSsubpoenafederal law enforcementGoogle

The electricity to an island goes out. To find the break in the underwater power cable, a ship pulls up the entire line or deploys remotely operated vehicles (ROVs) to traverse the line. But what if an autonomous underwater vehicle (AUV) could map the line and pinpoint the location of the fault for a diver to fix?

Such underwater human-robot teaming is the focus of an MIT Lincoln Laboratory project funded through an internally administered R&D portfolio on autonomous systems and carried out by the Advanced Undersea Systems and Technology Group. The project seeks to leverage the respective strengths of humans and robots to optimize maritime missions for the U.S. military, including critical infrastructure inspection and repair, search and rescue, harbor entry, and countermine operations.

"Divers and AUVs generally don't team at all underwater," says principal investigator Madeline Miller. "Underwater missions requiring humans typically do so because they involve some sort of manipulation a robot can't do, like repairing infrastructure or deactivating a mine. Even ROVs are challenging to work with underwater in very skilled manipulation tasks because the manipulators themselves aren't agile enough."

Beyond their superior dexterity, humans excel at recognizing objects underwater. But humans working underwater can't perform complex computations or move very quickly, especially if they are carrying heavy equipment; robots have an edge over humans in processing power, high-speed mobility, and endurance. To combine these strengths, Miller and her team are developing hardware and algorithms for underwater navigation and perception — two key capabilities for effective human-robot teaming.

As Miller explains, divers may only have a compass and fin-kick counts to guide them. With few landmarks and potentially murky conditions caused by a lack of light at depth or the presence of biological matter in the water column, they can easily become disoriented and lost. For robots to help divers navigate, they need to perceive their environment. However, in the presence of darkness and turbidity, optical sensors (cameras) cannot generate images, while acoustic sensors (sonar) generate images that lack color and only show the shapes and shadows of objects in the scene. The historical lack of large, labeled sonar image datasets has hindered training of underwater perception algorithms. Even if data were available, the dynamic ocean can obscure the true nature of objects, confusing artificial intelligence. For instance, a downed aircraft broken into multiple pieces, or a tire covered in an overgrowth of mussels, may no longer resemble an aircraft or tire, respectively.

"Ultimately, we want to devise solutions for navigation and perception in expeditionary environments," Miller says. "For the missions we're thinking about, there is limited or no opportunity to map out the area in advance. For the harbor entry mission, maybe you have a satellite map but no underwater map, for example."

On the navigation side, Miller's team picked up on work started by the MIT Marine Robotics Group, led by John Leonard, to develop diver-AUV teaming algorithms. With their navigation algorithms, Leonard's group ran simulations under optimal conditions and performed field testing in calm waters using human-paddled kayaks as proxies for both divers and AUVs. Miller's team then integrated these algorithms into a mission-relevant AUV and began testing them under more realistic ocean conditions, initially with a support boat acting as a diver surrogate, and then with actual divers.

"We quickly learned that you need more sensing capabilities on the diver when you factor in ocean currents," Miller explains. "With the algorithms demonstrated by MIT, the vehicle only needed to calculate the distance, or range, to the diver at regular intervals to solve the optimization problem of estimating the positions of both the vehicle and diver over time. But with the real ocean forces pushing everything around, this optimization problem blows up quickly."

On the perception side, Miller's team has been developing an AI classifier that can process both optical and sonar data mid-mission and solicit human input for any objects classified with uncertainty.

"The idea is for the classifier to pass along some information — say, a bounding box around an image — to the diver and indicate, "I think this is a tire, but I'm not sure. What do you think?" Then, the diver can respond, "Yes, you've got it right, or no, look over here in the image to improve your classification," Miller says.

This feedback loop requires an underwater acoustic modem to support diver-AUV communication. State-of-the-art data rates in underwater acoustic communications would require tens of minutes to send an uncompressed image from the AUV to the diver. So, one aspect the team is investigating is how to compress information into a minimum amount to be useful, working within the constraints of the low bandwidth and high latency of underwater communications and the low size, weight, and power of the commercial off-the-shelf (COTS) hardware they're using. For their prototype system, the team procured mostly COTS sensors and built a sensor payload that would easily integrate into an AUV routinely employed by the U.S. Navy, with the goal of facilitating technology transition. Beyond sonar and optical sensors, the payload features an acoustic modem for ranging to the diver and several data processing and compute boards.

Miller's team has tested the sensor-equipped AUV and algorithms around coastal New England — including in the open ocean near Portsmouth, New Hampshire, with the University of New Hampshire's (UNH) Gulf Surveyor and Gulf Challenger coastal research vessels as diver surrogates, and on the Boston-area Charles River, with an MIT Sailing Pavilion skiff as the surrogate.

"The UNH boats are well-equipped and can access realistic ocean conditions. But pretending to be a diver with a large boat is hard. With the skiff, we can move more slowly and get the relative motion in tune with how a diver and AUV would navigate together."

Last summer, the team started testing equipment with human divers at Michigan Technological University's Great Lakes Research Center. Although the divers lacked an interface to feed back information to the AUV, each swam holding the team's tube-shaped prototype tablet, dubbed a "tube-let." The tube-let was equipped with a pressure and depth sensor, inertial measurement unit (to track relative motion), and ranging modem — all necessary components for the navigation algorithms to solve the optimization problem.

"A challenge during testing was coordinating the motion of the diver and vehicle, because they don't yet collaborate," Miller says. "Once the divers go underwater, there is no communication with the team on the surface. So, you have to plan where to put the diver and vehicle so they don't collide."

The team also worked on the perception problem. The water clarity of the Great Lakes at that time of year allowed for underwater imaging with an optical sensor. Caroline Keenan, a Lincoln Scholars Program PhD student jointly working in the laboratory's Advanced Undersea Systems and Technology Group and Leonard's research group at MIT, took the opportunity to advance her work on knowledge transfer from optical sensors to sonar sensors. She is exploring whether optical classifiers can train sonar classifiers to recognize objects for which sonar data doesn't exist. The motivation is to reduce the human operator load associated with labeling sonar data and training sonar classifiers.

With the internally funded research program coming to an end, Miller's team is now seeking external sponsorship to refine and transition the technology to military or commercial partners.

"The modern world runs on undersea telecommunication and power cables, which are vulnerable to attack by disruptive actors. The undersea domain is becoming increasingly contested as more nations develop and advance the capabilities of autonomous maritime systems. Maintaining global economic security and U.S. strategic advantage in the undersea domain will require leveraging and combining the best of AI and human capabilities," Miller says.