EO-1 Advanced Land Imager overview and spatial performance

The Advanced Land Imager (ALI) is the primary instrument flown on the first Earth Observing mission (EO-1), which was developed under NASA´s New Millennium Program (NMP). The ALI contains a number of innovative features. These include the basic instrument architecture which employs a push-broom data collection mode, a wide field of view optical design, compact multi-spectral detector arrays, non-cryogenic HgCdTe for the short wave infrared bands, silicon carbide optics, and a multi-level solar calibration technique. The sensor includes detector arrays that operate in ten bands, one panchromatic, six VNIR and three SWIR, spanning the range from 0.433 to 2.35 μm. This paper describes the instrument design, provides an overview of the ground testing and calibration of the instrument and a summary of the sensor performance in space. In particular, the spatial imaging performance of ALI is discussed. Sample images are shown that demonstrate the improved capability of the sensor in terms of Pan band resolution and signal-to-noise ratio in all bands. On-orbit images have been analyzed and the results are compared with pre-launch calibrations. The instrument performance appears to meet all expectations