Field registration and test for multi-module imaging spectrometer

Field of view is a principle parameter of the push-broom imaging spectrometer which mainly affects its working efficiency. Integration of multiple sub-modules with smaller field of view is an optional solution to gain wider field of view. An approach for field registration and test for multi-module imaging spectrometer is presented. A single beam is reflected by multiple angle-tunable mirrors into multiple beams with different directions, which then enter the multimodule imaging spectrometer. Thus, one sub-module responses to lights with multiple incident angles simultaneously. A field registration platform is designed, which includes a collimating beam simulator, a multi-field beam generator, and an instrument support frame. The collimating beam simulator is composed of a collimator, an illuminant source, and a twodimensional shift pinhole target placed in the collimator focal plane. The multi-field beam generator is composed of a rotary table and multiple angle-tunable mirrors. The postures and the numbers of the mirrors are determined by the field registration requirement of the multi-module imaging spectrometer. Field registration is operated by monitoring the pixel response of the sub-module detector, and is tested by the two-dimensional shift of the pinhole target. Field registration was implemented on the platform for an airborne multi-module imaging spectrometer. Test result showed that the field registration is less than 0.2 pixels. Flight data of the imaging spectrometer demonstrated its good field registration alignment, which verified the engineering feasibility and value of the field registration approach.