Impact of recent enhancements and upgrades of the Advanced Solid-State Array Spectroradiometer (ASAS)

Several improvements have recently enhanced the Advanced Solid-State Array Spectroradiometer (ASAS) performance. First, the original charge injection device (CID) array was replaced by a new charge coupled device (CCD) array. This replacement required the development of a new night data system and new array drive and acquisition electronics. As a result, the instrument is now capable of acquiring data for 62 visible/near-infrared spectral bands (sensor capabilities have been increased from 29 bands) with improved spectral resolution and radiometric sensitivity. Second, the original pointing platform was replaced with one that allows the sensor to “look” forward 72° and backward -55° from nadir and compensates for aircraft yaw due to drift. Third, a custom fore-optic filter was developed to “flatten” the sensor´s spectral response, thus, increasing the signal-to-noise ratio for the blue and near-infrared bands. The authors describe are several of the technical innovations made during the development of these ASAS upgrades and the resultant instrument specifications