SEAHAWK is a new lidar for deep-water bathymetric surveying. Its performance and SWaP objectives generated requirements for the optical design affecting aperture, FOV, transmission efficiency, alignment accuracy, spectral filtering, and system size. Fabrication and other hardware limitations added constraints, particularly on the apertures of the detectors, filters, and custom scanner optics. An initial thin lens analysis produced a 3-channel receiver layout leading to the fabrication of an all-aluminum 300 mm diameter F/3.6 Cassegrain telescope having a total physical length less than 200 mm. An optimization of the relay optics maximized the narrowband filter performance by keeping the incidence angle constant across the system’s 38 mrad FOV. The resulting compact optical subsystem yields a smaller lidar head than other deep-water bathymetric lidars.
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