The Staring Spotlight mode is only available for a few sensors. It follows the same principle of antenna steering in azimuth direction as the standard Spotlight mode, except that the rotation center of the antenna for steering is situated at a nearer range position, within the illuminated scene. This induces that the illuminated antenna footprint stays almost the same during the whole acquisition. Contrarily to the Spotlight mode, the antenna footprint does not slide along the azimuth direction during the SAR acquisition. Additionally, the steering angle is higher for the Staring Spotlight mode than for the standard Spotlight mode, increasing therefore the length of the synthetic aperture and leading to an even higher resolution in azimuth direction.
The Staring Spotlight mode is implemented on the X-Band sensor TerraSAR-X since 2013 and achieves an azimuth resolution up to 0.25 m. Similar to the standard Sportlight mode, this happens to the detriment of the coverage. The scene size is highly dependent of the incidence angle and varies from 7.5 km to 4 km in range and from 2.5 to 2.7 km in azimuth direction. A larger coverage is obtained for smaller incidence angles.
Due to their extremely high resolution, staring spotlight acquisitions are principally used for the observation and/or monitoring of small scale objects and phenomena, e.g. small landslides, or for tomographic analysis.