The Charles Stark Draper Laboratory, Inc.

Harvard College

Other

Stephen P Smith

Juha-Pekka J Laine

Benjamin F Lane

Gregory P Blasche

Robin Mark Adrian Dawson

Erik L Waldron

Joseph M Kinast

Matthew T Jamula

Paul A Bohn

Richard E Stoner

Robin Dawson

Eric T Hoke

Daniel M Meiser

George M Whitesides

Younan Xia

Enoch Kim

Milan Mrksich

Rebecca Jane Jackman

Murali V Chaparala

Christian Marzolin

William W Whitacre

Mara G Prentiss

Xiao-Mei Zhao

William P Kelleher

Michael A Aucoin

Francis J Rogomentich

Robert A Larsen

Cort Nolan Johnson

Jeffrey D Jungemann

Peter A Lewis

Sean McClain

Paul A Ward

Farhad Zarinetchi

Matthew A Sinclair

Michael Kishinevsky

Walter D Foley

Simone B Bortolami

John James Boyle

Charles Arant

Reinhardt Leon Willig

Matthew Soucy

Timothy J McCarthy

Jeffrey A Korn

David M S Johnson

Samuel W Harrison

Robin M A Dawson

David L Butts

Jennifer T Choy

Nicole Pomeroy

Nancy Wu

William Ostrowski

Charles A McPherson, Jr

Jacques P Govignon

Adam J Saltzman

Krish Kotru

Justin M Brown

Erik Waldron

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 wide field-of-view celestial sighting system and method are provided. The method includes orienting an imaging optic to collect light from at least one light source, such as at least one celestial body, the imaging optic being secured to a platform. The method further includes selectively collecting light from the at least one celestial body through a selective light collector secured to the platform and positioned in an imaging surface, such as an imaging plane, of the imaging optic. The method further includes combining forward scattered light from the at least one celestial body to provide a combined forward scattered light, and detecting a light intensity of the combined forward scattered light. Systems for performing the method are provided.

Through-cloud celestial sighting system

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 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 probabilistic landmark navigation system is arranged to obtain from one or more image sensors one or more terrain images of a target terrain to be traversed by a vehicle. The terrain images are characterized by multiple individually non-distinctive terrain features without distinctively identifiable landmark features. The non-distinctive terrain features in the one or more terrain images are compared to map database information to make a non-temporal probabilistic determination of absolute location coordinates to associate with the non-distinctive terrain features. Then a navigation path is determined for the vehicle across the target terrain based on the absolute location coordinates.

Probabilistic landmark navigation (PLN) 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. 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 fiber optical sensor and methods for sensing a physical quantity such as rotation using the same. The sensor has an optical fiber supporting propagation of light that is configured as an interferometer. One or more segments of the optical fiber, where the segments may be non-contiguous, are poled in such a manner that a phase shift in light propagating through the fiber is created in response to application of a voltage to an electrode thereby inducing an electric field across a poled segment of the fiber. A phase modulator comprising multiple poled segments is additionally described. Applying phase-shifting effects differentially across poled segments of optical fibers of an array of optical fibers may also allow for steering an optical beam.

Segmented poled optical fiber for fiber optic sensor and phased array

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

Methods and apparatus that provide for inertial sensing. In one example, a method for inertial sensing includes trapping and cooling a cloud of atoms, applying a first beam splitter pulse sequence to the cloud of atoms, applying one or more augmentation pulses to the cloud of atoms subsequent to applying the first beam splitter pulse sequence, applying a mirror sequence to the cloud of atoms, applying a one or more augmentation pulses to the cloud of atoms subsequent to applying the mirror sequence, applying a second beam splitter pulse sequence to the cloud of atoms subsequent to applying the second augmentation pulse, modulating at least one of a phase and an intensity of at least one of the first and the second beam splitter pulse sequences, performing at least one measurement on the cloud of atoms, and generating a control signal based on the at least one measurement.

Atom interferometry in dynamic environments

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 folded optical system includes a powered optical element, at least one folding mirror and an aperture and defines an optical path through the optical system. The powered optical element, the at least one folding mirror and the aperture are configured to fold the optical path at the aperture, thereby providing a compact optical system. The optical system may include an optical block that totally internally reflects the optical signal at the aperture. Optionally or alternatively, discrete optical components may be used, such as an aperture made of a conventional material or a metamaterial, an off-axis parabolic mirror or lens and one or more folding mirrors. Some embodiments include a wavelength dispersive element, so as to implement a spectrometer.

Aperture-fold imaging system

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

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Acton, MA, United States of America

Stephen P Smith