Details on the first linear arrays of 512×3 VO_x microbolometers operating in space are reported. Arrays of this format are suited for remote sensing where relative motion between the spacecraft and target provides an inherent scanning mechanism. To take full advantage of the linear format, the array is built on a custom readout electronics that enables simultaneous integration of all pixels for scanning periods of up to 140 ms. The output signal from each pixel is digitized to 14 bits using a voltage-to-frequency conversion mechanism. Two arrays, integrated into two spectrally distinct radiometric packages, provide for coregistration of infrared images in three bands centered at 3.8, 10.85, and 11.85 μm for the retrieval of fire and sea surface temperatures. Analysis of the downlinked data confirms the reliable in-orbit operation and consistency with pre-launch characteristics for both arrays. Algorithms have been developed to perform post processing and absolute radiometric calibration of images in all bands. Image deconvolution using Wiener filtering was found effective in recovering the signal loss incurred in the active pixels when observing high temperature events. The in-flight gain and offset values were evaluated for all pixels by means of deep space measurements and cross calibration with reference spaceborne sensors. Preliminary assessment of the images calibrated using these values showed that they are in agreement with those retrieved from GOES sensor.

Date Published: 9 March 2013
PDF: 12 pages
Proc. SPIE 8614, Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS and Nanodevices XII, 86140N (9 March 2013); doi: 10.1117/12.2004641

Published in SPIE Proceedings Vol. 8614:
Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS and Nanodevices XII
Rajeshuni Ramesham; Herbert R. Shea, Editor(s)