As cities build taller and dig deeper, the ground beneath them is shifting under the weight. On Thursday, Ottawa-based CATALYST (PCI Geomatics), launched a new satellite tool to monitor this hidden strain.
The system, called UrbanSAR, was recently put to the test in Toronto’s Yonge and Eglinton neighbourhood, one of Canada’s most active construction zones. With dozens of high-rises going up directly above a new subway extension and next to older buildings, area residents have experienced sinkholes, cracked pavement, and road closures.
Using Interferometric Synthetic Aperture Radar (InSAR) satellite data, UrbanSAR was able to scan the entire neighbourhood and detected up to 30 millimeters of movement in the upper floors of newly built towers—areas that ground-based monitors usually miss.
Traditionally, keeping an eye on construction safety meant physically attaching sensors to a building.
“Ground sensors are precise, but they only tell you what is happening for one point on the ground,” explained Kevin Jones, Chief Product Officer at PCI Geomatics. If a sensor is attached to one tower, it cannot monitor the subway tunnel underneath or the street next door. Trying to cover an entire city with these physical sensors can cost millions of dollars and still leave dangerous blind spots.
Instead, UrbanSAR uses radar signals from orbiting satellites to measure millimeter-scale shifts from space. The software strips away the visual clutter of densely packed skyscrapers, isolating individual buildings to measure how they lean or sink, floor by floor.
The service is now available globally. According to the company, the technology can deliver these continuous, corridor-wide insights at a fraction of the cost of traditional ground surveys.
June McAlarey, CEO at PCI Geomatics, noted that this bird’s-eye view gives construction firms, city planners, and insurers the hard evidence they need to manage the risks of rapid urban densification. With countries like Australia and the United Kingdom already beginning to mandate satellite monitoring for urban construction projects, tracking our cities from space may soon become the new normal.