The Charles Stark Draper Laboratory, Inc.

Robin Mark Adrian Dawson

Juha-Pekka J Laine

Benjamin F Lane

Stephen P Smith

Gregory P Blasche

Matthew T Jamula

Murali V Chaparala

Joseph M Kinast

Paul A Bohn

William W Whitacre

Eric T Hoke

Daniel M Meiser

Erik L Waldron

Michael A Aucoin

Charles Arant

Cort Nolan Johnson

Peter A Lewis

Jeffrey D Jungemann

Steven Jay Spector

Matthew A Sinclair

Walter D Foley

Sean McClain

Juha Pekka Laine

Michael G Moebius

Jeffrey A Korn

Samuel W Harrison

Francis J Rogomentich

Simone B Bortolami

John James Boyle

Timothy J McCarthy

Charles A McPherson, Jr

A distributed navigation system includes navigation platforms, each having a universal navigation processor, relative navigation systems to provide source information to the navigation platforms, navigation filters provided on one or more of the universal navigation processors, and an anchor navigation node disposed on one or more of the navigation platforms to form one or more anchor navigation platforms. Each anchor navigation node includes an inertial navigation system, a clock, and absolute navigation systems, which are used, in combination with source information, to determine navigation information. The anchor navigation platforms provide the navigation information to other navigation platforms. The system further includes a navigation processor system in communication with the universal navigation processors to provide operating information updates to the universal navigation processors and a graphical user interface to display the navigation information to a user and permit the user to review and control the navigation information.

Multi-source distributed navigation system architecture

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

A distributed navigation system architecture includes a plurality of navigation platforms, each having a universal navigation processor configured to communicate with other universal navigation processors, one or more relative navigation systems configured to provide source information to the navigation platforms, an anchor navigation node disposed on one or more of the plurality of navigation platforms in order to form one or more anchor navigation platforms, the anchor navigation node, including an inertial navigation system, a clock, and one or more absolute navigation systems, configured to determine navigation information based on the inertial navigation system, the clock, the one or more absolute navigation systems and optionally the source information, the one or more anchor navigation platforms providing the navigation information to the other navigation platforms, and a navigation processor system in communication with each of the universal navigation processors in order to provide operating information updates to the universal navigation processors.

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 single photon detection circuit is described that includes a germanium photodiode that is configured with zero voltage bias to avoid dark current output when no photon input is present and also is configured to respond to a single photon input by generating a photovoltaic output voltage. A single electron bipolar avalanche transistor (SEBAT) has a base emitter junction connected in parallel with the germanium photodiode and is configured so that the photovoltaic output voltage triggers an avalanche collector current output.

Single electron transistor triggered by photovoltaic diode

An optical communications system comprises a first node comprising a phased array transmitter for generating an optical beam and a receiver, and a second node comprising a phase conjugate mirror for returning the optical beam to be detected by the receiver of the first node. The phased array transmitters allow for electronic steering of the beams in a way that is much faster and with a potentially smaller physical footprint than the mechanical systems. The phase conjugate mirrors return the received beams of photons back over the exact path they were sent from the phased array transmitters, ensuring continuity of communication even in the presence of atmospheric turbulence.

Optical communications system phase-controlled transmitter and phase-conjugate mirror receiver

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.

A star tracker determines a location or orientation of an object, such as a space vehicle, by observing unpolarized light from one or more stars or other relatively bright navigational marks, without imaging optics, pixelated imaging sensors or associated pixel readout electronics. An angle of incidence of the light is determined by comparing signals from two or more differently polarized optical sensors. The star tracker may be fabricated on a thin substrate. Some embodiments have vertical profiles of essentially just their optical sensors. Some embodiments include micro-baffles to limit field of view of the optical sensors.

Star tracker

Scattered light in the sky (sky glow) from light sources at one or more known geographic locations is used as reference point(s), from which geographic location of a system observing the sky glow is automatically ascertained. The light is scattered by particulates in the atmosphere. An upward looking camera captures an image of the sky, including the sky glow. A search engine automatically searches a catalog of modeled or pre-stored sky glows for a model that matches the image. Each model is associated with a geographic location. The models characterize each sky glow, such as in terms of color, intensity, etc., as the sky glow would appear from the associated geographic location. If a matching model is found, within a predetermined match criterion, the system outputs the geographic location associated with the matching model. Optionally, the geographic location is used to select and display a map of the geographic location.

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Waltham, MA, United States of America

Robin Mark Adrian Dawson