The Charles Stark Draper Laboratory, Inc.

Matthew T Jamula

Juha-Pekka J Laine

Benjamin F Lane

Robin Mark Adrian Dawson

Stephen P Smith

Gregory P Blasche

Eric T Hoke

Daniel M Meiser

Paul A Bohn

Murali V Chaparala

Matthew A Sinclair

Joseph M Kinast

Charles Arant

Adam F Kelsey

Adam Parolin

Jeffrey A Korn

Erik L Waldron

Samuel W Harrison

Walter D Foley

Francis J Rogomentich

John James Boyle

Robin M A Dawson

Simone B Bortolami

Sean McClain

Timothy J McCarthy

A navigation system includes a star camera having a field of view. The star camera includes a sun shields that selectively block portions of the star camera's field of view, to prevent unwanted light, such as light from the sun or moon, reaching image sensors of the star cameras. Some sun shields include x-y stages or r-θ stages to selectively position a light blocker to block the unwanted light. Some sun shields use positionable partially overlapping orthogonally polarized filters to block the unwanted light. Some sun shields use counter-wound spiral windows that are selectively rotated to block the unwanted light. Some sun shields a curved surface that defines a plurality of apertures fitted with individual mechanical or electronic shutters.

Star tracker with adjustable light shield

An image-based navigation system is arranged to obtain a terrain image of a target terrain from one or more image sensors at a low altitude imaging location. The terrain image includes at least one celestial image feature and at least one terrain feature. Map database information stored in at least one hardware memory device is accessed and compared to the at least one celestial image feature and the at least one terrain feature in the terrain image to determine absolute location coordinates of the imaging location.

Stellar-landscape/horizon image navigation

A navigation system includes a monocentric lens and one or more curved image sensor arrays disposed parallel and spaced apart from the lens to capture respective portions, not all, of the field of view of the lens.

Navigation system with monocentric lens and curved focal plane sensor

Methods and apparatus automatically determine a location, such as of an aircraft or spacecraft, by matching images of terrain below the craft, as captured by a camera, radar, etc. in the craft, with known or predicted terrain landmark data stored in an electronic data store. A star tracker measures attitude of the camera. An additional navigation aiding sensor provides additional navigational data. Optionally, a rangefinder measures altitude of the camera above the terrain. A navigation filter uses the attitude, the additional navigational data, and optionally the altitude, to resolve attitude, and optionally altitude, ambiguities and thereby avoid location solution errors common in prior art terrain matching navigation systems.

Star tracker-aided airborne or spacecraft terrestrial landmark navigation system

A digital camera optically couples a monocentric lens to image sensor arrays, without optical fibers, yet shields the image sensor arrays from stray light. In some digital cameras, baffles are disposed between an outer surface of a monocentric lens and each image sensor array to shield the image sensor arrays from stray light. In other such digital cameras, an opaque mask defines a set of apertures, one aperture per image sensor array, to limit the amount of stray light. Some digital cameras include both masks and baffles.

Hemispherical star camera

A visual navigation system includes a compass configured to orient a user in a heading direction, an image sensor configured to capture a series of successive navigation images in the heading direction, one or more of the navigation images having at least two reference markers, data storage memory configured to store the series of successive navigation images, a navigation processor configured to identify at least one principal marker and at least one ancillary marker from the at least two reference markers, the principal marker positioned within a principal angle and the ancillary marker positioned within an ancillary angle, which is greater than the principal angle, and to determine heading direction information based on a position of the at least one principal marker and/or the at least one ancillary marker in the successive navigation images, and a user interface configured to provide the heading direction information to the user.

Camera-based heading-hold navigation

A star tracker includes a lens slice, a pixelated image sensor, an ephemeral database and a processor configured to estimate attitude, orientation and/or location of the star tracker based on an image of one or more celestial objects projected by the lens slice onto the pixelated image sensor. The lens slice is smaller and lighter than an optically comparable conventional lens, thereby making the star tracker less voluminous and less massive than conventional star trackers. A lens slice is elongated along one axis. Optical performance along the elongation axis is comparable to that of a conventional circular lens of equal diameter. Although optical performance along a width axis, perpendicular to the elongation axis, of a lens slice can be significantly worse than that of a conventional lens, use of two orthogonal lens slices provides adequate optical performance in both axes, and still saves volume and mass over a conventional lens.

Sliced lens star tracker

A configurable optical baffling includes an outer housing positioned above a fixed platform and has an outer opening. An inner housing is layered below the outer housing and above the fixed platform and has inner openings and inner shaded sections. The outer opening includes an elongated sensing boresight having a longitudinal boresight axis and opposing ends. An outer boresight opening end is open to the light from the scene, and a reflecting end has a flat fold mirror that is configured to reflect light from the outer boresight opening in towards the inner housing so that the optical baffling is configured to receive light from the scene solely from a single look direction along the boresight axis, the single look direction being changeable by rotation of the outer housing.

Configurable optical baffling for use with multiple-field-of-view optical sensor system

A configurable sunshade for use with a multiple-camera system that has multiple camera sensors with associated fields of view. The sunshade has multiple portions that are independently rotatable with respect to a fixed platform such that in distinct orientations with respect to each other, specified cameras may be blocked from receiving light from a scene, in whole or in part. In other embodiments, individual apertures of a multi-sunshade housing may be separately activated.

Configurable sunshade for use with multiple-field-of-view camera system

Methods and apparatus automatically determine a location, such as of an aircraft or spacecraft, by matching images of terrain below the craft, as captured by a camera, radar, etc. in the craft, with known or predicted terrain landmark data stored in an electronic data store. A star tracker measures attitude of the camera. Optionally, a rangefinder measures altitude of the camera above the terrain. A navigation filter uses the attitude, and optionally the altitude, to resolve attitude, and optionally altitude, ambiguities and thereby avoid location solution errors common in prior art terrain matching navigation systems.

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Wilmington, MA, United States of America

Matthew T Jamula