Recent studies have demonstrated the potential for exploring spectral discriminates in the thermal infrared for day/night surveillance and targeting of military targets in situations where the thermal contrast is low. Although the spectral discriminates have been found to be very subtle in most cases, good detection performance is achievable due to the generally high band-to-band spectral correlation of the background. This, however, presents a challenging set of requirements for infrared multispectral and hyperspectral sensors designed for this application. In this paper, we examine the merits and limitations of various design approaches, including imaging Michelson interferometers, dispersive spectrometers, and spatial Fourier transform spectrometers. The comparison is based on detailed sensor modeling as well as laboratory and field measurements of state-of-the-art instruments: a dispersive spectrometers and a n imaging Fourier transform spectrometer. The primary emphasis of this paper is the design of a hyperspectral sensor for tower-based and subsequent airborne data collection. Implications for operational multispectral sensor designs are also given.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.