Johns Hopkins University

Other

Yanping Guo

Carl V Nelson

Harvey Wayne Ko

David M White

Shouxiang Hu

A method and apparatus for autonomous navigation for deep space missions using the sun as the reference body and determining the spacecraft orbit based on observations made on the sun using onboard instruments. Two types of observation data, the direction of the spacecraft relative to the sun as a function of time and the optical Doppler shift due to the motion of the spacecraft relative to the sun, can be used for the spacecraft orbit determination. A dual imaging system which functions as a sun imager taking images of the sun against star backgrounds during the cruise phase and as a regular optical imager taking pictures of the targeting planetary body during the approaching phase is also described.

Method and apparatus for autonomous solar navigation

A unique time-domain electromagnetic system and data processing technique which, using low frequency electromagnetic fields, can localize, in three-dimensions, the position of buried metallic objects is disclosed. The measurement system uses time-domain electromagnetic techniques on a scanning frame similar to a X-Y plotter. The system collects magnetic data over a large area above the buried object. The spatial information of the field detected on the ground is then processed with an unique 'nearfield holographic' data processing method to reconstruct the field image of the buried object.

Apparatus with movable receiver coil array for locating a buried metallic object

An electrooptical deflector that overcomes conventional geometry limitations and can deflect an optical beam at high speed with high deflection angle and high resolution. It comprises an array of waveguide optical channels having an electrooptical layer sandwiched between a bottom and a top electrodes. Either the top electrode further comprises two sets of prism-shaped electrodes; or, the electrooptical layer further comprises two sets of prism-shaped spontaneous polarization domain regions. Linear phase differences are induced among a group of sub-light beams travelling in the individual optical channels. After leaving the individual optical channels, the sub-light beams are merged and the merged light beam is deflected along a direction depending on a voltage or a pair of voltages applied between the top and bottom electrodes. The optical defector requires one or a pair of low driving voltage(s) with a simple driving scheme. It is suitable for many important applications, such as optical switching, high quality retinal display in potable computer, video and virtual reality devices, optical processing, pattern recognition, laser printing and bar code scanning.

Optical deflector

A unique time-domain electromagnetic system and data processing technique which, using low frequency electromagnetic fields, can localize, in three-dimensions, the position of buried metallic objects is disclosed. The measurement system uses time-domain electromagnetic techniques on a scanning frame similar to a X-Y plotter. The system collects magnetic data over a large area above the buried object. The spatial information of the field detected on the ground is then processed with an unique `nearfield holographic` data processing method to reconstruct the field image of the buried object.

Imaging objects in a dissipative medium by nearfield electromagnetic

An electron beam addressed electro-optical (EO) light valve (EOLV) having a matrix of openings formed on and extending through an input conductive layer and further extends into an electrically insulating layer. A partially conductive coating is formed on the surface of each opening in the insulating layer, and has a substantially good electrical contact with the input conductive layer. An EO layer, formed of either a liquid crystal (LC) or a solid state EO crystal, is positioned on the optical output side of the insulating layer. Through the openings electrons from a scanning electron beam can reach and be directly deposited on the partially conductive coatings at a depth substantially close to the EO layer and substantially far away from the input conductive layer. The insulating material surrounding the openings in the insulating layer strictly prevents these deposited electrons from inter-opening motion. These deposited electrons are then discharged along the partially conductive coatings to the input conductive layer before the next scanning cycle. Accordingly, a precisely controllable voltage across each pixel of the EO layer can be obtained. This makes it possible to obtain a precisely controllable orientation state of the molecules in each pixel of the EO layer corresponding to the modulation of the scanning electron beam. Thus an EOLV with significantly high resolution, high contrast ratio, fast response speed, high display gray scale and high sensitivity responding to the input modulation can be achieved according to this invention.

Growing community of inventors

Silver Spring, MD, United States of America

Yanping Guo