Developed by Aloft Sensing in collaboration with NASA, the compact radar system is designed for high-altitude, long-endurance (HALE) platforms. Its ability to capture extremely sensitive surface data without relying on GPS makes it a significant innovation in Earth observation and potentially space-based missions.
By detecting millimeter-scale movements, from subtle changes before a volcanic eruption to snowpack loss, the radar could provide early warnings for natural disasters, with applications in both science and national security.
The Problem With Existing Systems
Traditional radar systems that use interferometric synthetic aperture radar (InSAR) techniques can track surface deformation and terrain change. But these instruments are typically large, power-hungry, and too heavy for HALE platforms which are designed to stay aloft for weeks, months, or even years.
These systems can revisit the same location multiple times an hour, making them ideal for monitoring fast-evolving environments. However, conventional InSAR instruments are simply too big and power-intensive to be used on lightweight HALE vehicles.
A Compact Solution With High Precision
The HALE InSAR system, supported by NASA’s Earth Science Technology Office (ESTO), addresses this size and weight challenge head-on. Weighing under seven kilograms (15 pounds) and consuming less than 300 watts of power, the radar is built for compact platforms without compromising performance.
Despite its small form, it can detect surface deformation at the millimetre scale and capture vertical terrain data with centimeter-level accuracy. These capabilities surpass what was thought possible on such a small scale.
The engineers behind this were able to introduce such advanced tech by drawing on earlier NASA-funded projects, including a software-defined transceiver and a lightweight electronically steered antenna, developed under ESTO’s Instrument Incubation and Decadal Survey Incubation programmes.
Phased Array Without the Bulk
A standout feature of HALE InSAR is its flat, tablet-sized phased array antenna. This electronically steered antenna lets users redirect the radar beam without physically moving the device. This removes the need for heavy gimbals and further reduces its weight.
With each pulse, the radar rapidly alternates its view from side to side, capturing two synthetic aperture radar (SAR) images nearly simultaneously. This feature expands the instrument’s versatility, especially for platforms with strict weight constraints.
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Navigation Without GPS
Another key aspect of the HALE InSAR is that it doesn't need GPS to determine its position. Instead, it uses advanced onboard algorithms that analyze radar signal feedback to calculate its exact location.
This GPS-free navigation is crucial for operating in remote or GPS-denied environments, including disaster zones, polar regions, and high-security areas. It also positions the radar as a viable option for civil and defence missions, including those in space.
Proven Performance at High Altitudes
The Aloft Sensing team recently completed successful tests of HALE InSAR at 65,000 feet, using an airship and small stratospheric balloons. These early tests are important milestones, proving the system’s ability to operate in near-space conditions.
Next, the team plans to test HALE InSAR aboard a fixed-wing HALE aircraft. In the long term, the radar may be deployed aboard small satellites in low Earth orbit, opening up possibilities for global monitoring with frequent revisits and minimal infrastructure.
From Prototype to Dual-Use Technology
The compact radar system offers clear benefits for civil applications like environmental monitoring and natural disaster prediction, while also attracting interest from the defence sector. With its evolving design and tested high performance, HALE InSAR could have a significant impact on airborne, suborbital, and potentially orbital Earth observation missions.
Reference
NASA-funded Compact Radar Drives Big Changes in Airborne and Suborbital Radar Capabilities [Online] Available at https://science.nasa.gov/directorates/smd/earth-science-division/nasa-funded-compact-radar-drives-big-changes-in-airborne-and-suborbital-radar-capabilities/ (Accessed on 28 August 2025)
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