A digital communication system comprising: an optical receiver comprising a detector configured to receive a laser optical signal from an optical transmitter; a curved mirror; an optical detector associated with said curved mirror; and an automated tracking system configured to: (i) determine a desired orientation of said optical receiver in relation to said optical transmitter, based, at least in part, on detecting a celestial location of said optical transmitter, (ii) move said optical receiver to said orientation, and (iii) continuously adjust said orientation to maximize a measured strength of said received optical signal.

An optical baffle is provided that maximizes light reflection and absorption and, thus, enables a spacecraft camera to capture images of extremely faint objects, such as stars, while illuminated by a very bright source, such as the sun. The optical baffle may be manufactured by additive manufacturing techniques and unique materials to create unique geometry and very absorbent surfaces to trap light.

A star tracker includes imaging optics comprising a folding mirror, a lens, and a detector. The folding mirror bends light received from an optical axis through the lens that focuses the bent light onto the detector. The star tracker includes a steering mechanism that steers light from an adjustable field of view (FOV) to the optical axis of the imaging optics. The steering mechanism includes: (i) a first photonic crystal element comprising beam pointing spatially variant photonic crystals (SVPCs); (ii) a second photonic crystal element comprising beam pointing SVPCs that is positioned adjacent and axially aligned with the first photonic crystal element; and (iii) a housing that receives the first and second photonic crystal elements for independent rotation.

A dual-band (SWIR/visible) optical system operating based on Angles-Only Navigation technology. The SWIR module is optimized for imaging stars. The visible-light sensor is independently optimized for imaging satellites including GPS satellites at night. Preferred embodiment provides continuous high accuracy geo-position solutions day and night (including through the midnight hole, when solar-illuminated Low Earth Orbit (LEO) satellites are not available. Applicants have experimentally validated proposed system by imaging LEO satellites during terminator using a 1-inch diameter telescope and GPS satellites at night during midnight hole using a 5-inch telescope.

A multi-beam optical phased array on a single planar waveguide layer or a small number of planar waveguide layers enables building an optical sensor that performs much like a significantly larger telescope. Imaging systems use planar waveguides created using micro-lithographic techniques. These imagers are variants of phased arrays, common and familiar from microwave radar applications. However, there are significant differences when these same concepts are applied to visible and infrared light.

An image data capturing arrangement (1) has at least two image data capturing devices. At least one first image data capturing device (2) is adapted to capture data of one or more first images of an object along a first image capturing axis 4, and at least one second image data capturing device (6) is adapted to capture data of one or more second images of stars along a second image capturing axis 8. The second image capturing axis (8) has a known orientation relative to the first image capturing axis (4), and a reference clock for assigning a time stamp to each first and second image data.

Multiple mode star tracker methods and systems in which attitude information and image information is generated are provided. The multiple mode star tracker includes a detector having a plurality of pixels arranged in a focal plane array. The detector is operated to obtain multiple image frames from within a field of view containing a plurality of stars. For each of the image frames, the attitude of the detector and in turn the attitude of each pixel is determined. Based on the attitude quaternion of the individual pixels within a plurality of frames, image data from the plurality of frames is co-added or stacked to form a composite image. The co-addition of multiple frames of image data enables or facilitates the detection of dim objects by the multiple mode star tracker. Moreover, embodiments of the present disclosure enable the attitude quaternion for individual pixels within individual frames to be determined using the multiple mode star tracker function of the instrument, and without requiring attitude information provided by a separate device, such as a gyroscope.

An out-of-field rejection filter (OFRF) can be used in optical systems to reject stray light. Such optical systems can include cameras, projectors, star trackers, and virtual reality or augmented reality displays. The OFRF can include a converter to convert randomly polarized light to p-polarized light and an angular selectivity layer to select in-field p-polarized light and reject out-of-field p-polarized light. The converter and the angular selectivity layer are configured so as to filter out-of-field light while passing in-field light within a light bandwidth. The angular selectivity layer can be a multilayer film of interleaved materials having alternating permittivity and magnetic permeability properties.

A multi-beam optical phased array on a single planar waveguide layer or a small number of planar waveguide layers enables building an optical sensor that performs much like a significantly larger telescope. Imaging systems use planar waveguides created using micro-lithographic techniques. These imagers are variants of phased arrays, common and familiar from microwave radar applications. However, there are significant differences when these same concepts are applied to visible and infrared light.

A technique for polar aligning the mount of a telescope or other astronomical instrument includes acquiring star images from an electronic polar scope and determining a location of a celestial pole relative to the star images based on computerized matching of the star images to information in a database. The mount has a right-ascension (RA) axis, and the technique directs an adjustment to the mount so as to align a location of the RA axis with the determined location of the celestial pole.