The Charles Stark Draper Laboratory, Inc.

Massachusetts Institute of Technology

Murali V Chaparala

Juha-Pekka J Laine

Robin Mark Adrian Dawson

Benjamin F Lane

Stephen P Smith

Gregory P Blasche

Erik L Waldron

Matthew T Jamula

Robin Dawson

Charles Arant

Marc Steven Weinberg

Juha Pekka Laine

Vladimir Bulovic

Jonathan Jay Bernstein

Martin Arnold Schmidt

Steven Jay Spector

Eugene H Cook

Thomas A Campbell

Jianglong Chen

Peter G Sherman

Brent Hollosi

Zachary R Smigelski

Valerie Leblanc

Eric Wing-Jing Lam

Thayne R Henry

Stephen L Finberg

Geremy Freifeld

Wes Uy

Rob A Bousquet

Erik Waldron

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 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

A thermal event sensor includes a charge storage component formed on a substrate, configured to hold an initial charge, and configured to lose charge at a rate dependent upon temperature. A sensing interface is coupled to the charge storage component and a readout mechanism is coupled to the sensing interface. The readout mechanism senses a remaining charge on the charge storage component and provides a readout value indicative of the remaining charge.

Thermal event sensor

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

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

A chip scale star tracker that couples starlight into a lightguide such that the angle of incidence partially determines the mode of propagation of the starlight in the lightguide. A baffle system integrated with the lightguide prevents propagation of light incident from a predetermined range of angles.

Chip-scale star tracker

A star tracker has an electronically steerable point of view, without requiring a precision aiming mechanism. The star tracker can be strapped down, thereby avoiding problems associated with precision aiming of mechanical devices. The star tracker images selectable narrow portions of a scene, such as the sky. Each stellar sighting can image a different portion of the sky, depending on which navigational star or group of navigational stars is of interest. The selectability of the portion of the sky imaged enables the star tracker to avoid unwanted light, such as from the sun.

Star tracker with steerable field-of-view baffle coupled to wide field-of-view camera

Methods and apparatus for calibrating a gyroscope without rotating the instrument. In one example, a calibration method includes operating the gyroscope in a self-oscillation loop to generate x-axis and y-axis drive signals, adding forcing signals to the x-axis and y-axis drive signals to produce pick-off x-axis and y-axis signals, measuring the pick-off x-axis and y-axis signals to produce measurement data, determining a relative phase between the pick-off x-axis and y-axis signals, based on the measurement data and the relative phase, estimating parameters of the gyroscope, based on the measurement data and the estimated parameters, calculating estimated position signals to calibrate the gyroscope.

Calibration systems and methods for gyroscopes

A MEMS gyroscope is provided. A substrate can be formed with a substantially planar surface, a substantially hemispherical cavity extending into the surface, an actuation electrode, and a plurality of sensing electrodes. A resonator formed from a substantially hemispherical shell can be suspended within the cavity by a stem coupling the center of the bottom of the cavity to the center of the bottom of the shell. An electronic processor can be configured to cause a voltage to be applied to the actuation electrode, receive signals from the sensing electrodes, and process the received signals to determine rotation of the MEMS gyroscope.

MEMS hemispherical resonator gyroscope

A chip scale star tracker that captures plane-wave starlight propagating in free space with a wafer-thin angle-sensitive broadband filter-aperture, and directs the light into a waveguide structure for readout. Angular information about the star source is determined from characteristics of the starlight propagating in the waveguide. Certain examples include internal propagation-constant-based baffling to elimination stray light from extreme angles.

The disclosure relates to providing printed structures of polymer that have substantially flat printed surfaces. In one embodiment, the disclosure relates to a post-printing treatment apparatus for receiving a substrate supporting a polymer printing thereon. The polymer can be PMMA or other suitable polymer. In a related embodiment, the polymer defines a thermoplastic polymer having a glass transition temperature. The apparatus can comprise of a chamber, and input manifold, an exhaust manifold, a solvent reservoir and a gas reservoir. The solvent reservoir provides one or more solvent systems adapted to chemically bind, and potentially react, with the polymer. The gas reservoir provides one or more gases for drying the substrate and printed polymer after the solvent treatment step. In one application, a substrate having printed surface thereon is placed in the chamber and exposed to the solvent system for sufficient period of time to provide substantially flat print surfaces.

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Newton, MA, United States of America

Murali V Chaparala