The optical and electronic design of the Halogen Occultation Experiment (HALOE) elevation sun sensor is described. The HALOE instrument is a gas-correlation radiometer now being developed by NASA Langley Research Center for the Upper Atmosphere Research Satellite (UARS). The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic charge-coupled device. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the HALOE science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 0.7 µm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.
L. E. Mauldin,
A. S. Moore,
C. W. Stump,
L. S. Mayo,
"Digital Solar Edge Tracker For The Halogen Occultation Experiment," Optical Engineering 26(6), 266513 (1 June 1987). https://doi.org/10.1117/12.7974107