A shoebox-sized synthetic aperture radar (SAR) a hundred times lighter than standard equipment has been successfully tested on Boeing's ScanEagle unmanned aircraft.

Manufacturer ImSar claims its NanoSAR, which can see in hazy, cloudy, rainy or foggy conditions, is the world's smallest. It weighs just 900g, compared with existing devices of between 23kg and 90kg.

In a 90-minute test flight the ScanEagle flew over a target area taking in vehicles, structures and corner reflectors at a variety of attitudes and ranges. Data collected was used to create SAR imagery on ground-based equipment. The next test will be to create imagery aboard the aircraft in real-time.

Because of the weight of traditional SARs, their all-weather imaging capabilities have been restricted to larger aircraft. The NanoSAR would allow even the 18kg ScanEagle to carry an electro-optical or infrared camera and a SAR payload at the same time.

Logan Harris, ImSAR chief technology officer, said: 'SAR is the best tool to get certain jobs done, such as finding small vessels on the ocean. But because of the size, weight, power and cost of SAR systems, it just hasn't been possible to get this capability to the warfighter on a broader scale. NanoSAR has changed that.'