The Japan Defense Agency in Tokyo has completed a study of a multispectral sensor for airborne surveillance. The sensor, which the team described in the October 2000 issue of Optical Engineering, features off-axis three-mirror reflective optics.

Dichroic mirrors split incoming light into three visible and three IR bands. A linear array constructed of two 5000-element CCDs monitors the visible wavelengths from 400 to 760 nm and the near-IR from 800 to 920 nm. Linear arrays of HgCdTe monitor the 2.93- to 5.03-µm and 7.92- to 10.25-µm bands. In field tests, the sensor displayed a spatial resolution of 6.2 µrad in the visible and near-IR, and 84 and 104 µrad in the two mid-IR bands, respectively.