Co-boresighted dual-mode SAL/IR seeker including a SAL spreader

摘要

In a co-boresighted SAL/IR seeker, the optical system and particularly the secondary lens and position of the SAL detector are configured to produce a well-corrected spot of laser energy at the SAL detector. A spreader is positioned between the secondary mirror/lens and the SAL detector, possibly on the secondary mirror, away from the aperture stop and not in the optical path to the IR detector. The spreader is configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy at the SAL detector to set the system transfer function to meet slope requirements. Spatial homogenization serves to reduce both boresight shift and slope non-linearities. This approach greatly simplifies the time and labor intensive calibration of the SAL detector's system transfer function.