Can satellites find public infrastructure risks early?

Ageing public infrastructure is a financial burden and creates serious physical risks, but data from satellites could make a big difference.

Road cave-ins – stemming from deteriorating underground structures – are a persistent, and dangerous, societal concern. The authorities responsible face an uphill battle: they have limited budgets and personnel, making it almost impossible to inspect the vast network of assets thoroughly.

Current methods are slow and expensive, leaving organisations exposed to unseen risks. The standard approach relies on on-site visual inspections of systems like sewers or using vehicle-mounted ground-penetrating radar (GPR). These methods are laborious, costly, and can only cover small areas at a time. This piecemeal approach means comprehensive inspection of wide areas just isn’t practical.

The problem begins deep underground with cavity formation, which then progresses before a final and sudden collapse. Traditional satellite observation, which mainly captures surface conditions, has historically struggled to provide actionable data on these subsurface threats.

Using SAR satellites to find hidden public infrastructure risks

NTT has conducted the “world’s first successful demonstration” of a method to identify these early warning signs using Synthetic Aperture Radar (SAR) satellites. The technology leverages radio waves that can penetrate asphalt and analyses how they scatter to detect the three main precursors to a collapse: the formation of underground cavities, subsequent ground disturbance, and resulting surface unevenness.

The system works by analysing the scattering of radio waves sent with multiple polarisations. Different types of scattering correspond to different physical hazards. According to NTT’s research, ‘double-bounce reflection’ indicates the formation of an underground cavity, ‘volume scattering’ detects ground disturbance, and ‘surface scattering’ identifies unevenness on the road itself. By comparing data from satellites gathered at two different times, analysts can also assess the progression of these dangerous conditions affecting public infrastructure.

This allows for the detection of high-risk locations efficiently and without deploying on-site crews. NTT claims this satellite-only approach could reduce the costs associated with identifying underground cavities by approximately 85 percent when compared to traditional vehicle-mounted GPR. The company states the reliability of the technology has been checked against actual road cavity inspection data.

From data to real-world impact

Unlike predictive models that estimate risk by combining various data types like utility maps and environmental information, NTT says this method directly measures the physical conditions using SAR radio waves. NTT claims this allows for high-reliability detection using only the satellite data.

A key operational advantage of using data from satellites is the potential for regular public infrastructure monitoring. Infrastructure deterioration can be sudden, and periodic inspections every few years may miss any rapid development. Because SAR satellites orbit the Earth on a regular schedule, monitoring conditions more frequently than on-site inspections becomes easier. This continuous oversight capability is intended to reduce the risk of overlooking major cavity development.

This satellite-based solution is designed to detect cavities forming closer to the surface. NTT notes this new technology is complementary to another of its methods, an optical fibre-based ground monitoring system, which is designed to monitor the progression of deeper underground cavities. The company suggests that using both technologies together could allow for more reliable detection of cave-in signs at different depths.

NTT plans to move this technology from demonstration to practical implementation and will conduct further experiments in collaboration with local governments to improve its reliability. The stated goal is to work with municipalities and business partners to streamline inspection operations.

This work is part of NTT’s C89 brand, which focuses on using satellites to tackle all kinds of public infrastructure risks. For asset managers and public sector CTOs, this research points toward a data-driven model for infrastructure maintenance, potentially shifting budgets from costly physical inspections to more frequent and wide-area data analysis.

See also: SK Telecom: Why the AI infrastructure bottleneck matters

Want to learn about the IoT from industry leaders? Check out IoT Tech Expo taking place in Amsterdam, California, and London. The comprehensive event is part of TechEx and is co-located with other leading technology events, click here for more information.

Telecoms is powered by TechForge Media. Explore other upcoming enterprise technology events and webinars here.

Tags: applications, government, infrastructure, public sector, satellites, use cases