Improved image position sensor for high resolution optical tracking.
The narrow beamwidth of a laser source can provide advantages, relative to a microwave source, in applications such as short range, high angular resolution trackers. In such applications, an image position sensor (IPS) is used which senses the angle of arrival of the optical radiation from the target. It is shown analytically and empirically that, in the case of a rotating mirror IPS, cross coupling between azimuthal and elevation channels as well as nonlinear and saturation effects result when the image displacements on the rotating mirror are large compared to the image size. The performance of the rotating mirror IPS and consequently that of the tracker has been greatly enhanced by incorporating a computer generated variable density spatial filter (VDSF) in front of the rotating mirror.
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Subramanian
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