Aerospace Patents 2012
R. P. Patera, “Systems and Methods for Attitude Propagation for a Slewing Angular Rate Vector,” U.S. Patent No. 8,185,261, May 2012.
The attitude propagation of a vehicle can be determined accurately and easily if the angular rate vector points in a fixed direction with respect to the vehicle. However, most cases of interest involve angular rate vectors that change direction as a function of time. This invention is directed to computer-based systems and methods for propagating attitude for a moveable object (e.g., a space vehicle, a terrain vehicle, or other types of moveable objects). Since the slew rate of the angular rate vector causes attitude propagation error, this invention overcomes this problem by employing an additional coordinate frame that slews with the angular rate vector. In this new intermediate frame, the angular rate vector does not change direction and improves attitude propagation accuracy compared to prior attitude propagation techniques. For pure coning motion, this invention completely eliminates attitude propagation error.
H. G. Muller, H. I. Kim, and B. J. Foran, “Stable Lithium Niobate Waveguides, and Methods of Making and Using Same,” U.S. Patent No. 8,189,981, May 2012.
Electrooptically active devices have conventionally been prepared using lithium niobate. However, lithium niobate waveguides prepared using conventional proton exchange techniques are vulnerable to performance degradation, limiting their application. The resulting waveguide may also be unstable due to stresses caused by the ion exchange process. This invention provides stable lithium niobate waveguides with improved stability and methods for making and using them. Specifically, the waveguides may be fabricated using a plurality of steps, each of which inhibits the formation of performance-degrading defects. For example, a highrefractive index layer may be prepared using a soft proton exchange on a lithium ion substrate, in which an excess of lithium ions are provided to slow the proton exchange reaction, allowing more time for the protons to diffuse into the substrate and thus reducing defect-inducing stress. Such a proton exchange step may be followed by an annealing step during which a predetermined vapor pressure of water is applied over the substrate. The vapor pressure of water may be selected to inhibit dehydration of the substrate, reducing the formation of defects, and provide a specified stoichiometric ratio of niobium to oxygen in the proton-exchanged layer.
D. S. Kun and N. Morgan, “Constant False Alarm Rate Robust Adaptive Detection Using the Fast Fourier Transform,” U.S. Patent No. 8,194,766, June 2012.
Many conventional detectors are deficient in that their detection functionality depends on having an accurate estimate of the noise power. For example, some conventional detectors, under certain environments in which the signal-to-noise power ratio can change abruptly (e.g., wireless channels), cannot change their detection threshold without having to restart their numerical algorithm to estimate the noise power. This invention relates generally to signal detection and, in particular, to receivers and techniques that use the fast Fourier transform (FFT) to detect the presence of man-made signals and achieve a constant false alarm rate (CFAR) when only noise is present within a predetermined frequency band. The invention involves signal-detection techniques using FFT that instantaneously react to rapid changes in the signal while achieving a CFAR without resorting to calibration or collection methods to estimate the key statistical parameters of the environment in which the signal resides. The invention employs a decision rule that immediately adjusts to power fluctuations, which overcomes the disadvantage of prior signal-detection techniques of being unable to adapt immediately to abrupt changes in the environment. The invention derives the probability distribution of the decision statistic that results in a detection threshold that is independent of the noise variance, FFT window type, and the statistics of the environment.
R. B. Dybdal, S. J. Curry, F. Lorenzelli, et al., “Systems and Methods for Increasing Communications Bandwidth Using Non-Orthogonal Polarizations,” U.S. Patent No. 8,199,851, June 2012.
Dual polarization system designs allow two independent signals to be communicated in the same bandwidth, thus doubling the signal throughput. Example applications include direct broadcast satellite TV that allows twice the number of channels to be sent to subscribers. Mutual interference between the independent signals is avoided by design attention to passively and actively maintaining polarization orthogonality. Further increases in communication throughput require communicating independent signals on nonorthogonal polarizations. Mutual interference in this case is avoided by joint signal separation techniques that allow the separation of the independent signals from the composite signals used in their communication. An example embodiment referred to as quadrapol communicates four independent signals using four nonorthogonal polarizations to increase the throughput by a factor of four, compared to the conventional dual polarization designs that double the communication throughput.
S. La Lumondiere and T. Yeoh, “Refraction Assisted Illumination for Imaging,” U.S. Patent No. 8,212,215, July 2012.
One method of imaging through substrate material is conventional bright field microscopy. While this technique can be relatively inexpensive, the resolution of the resulting images is often disappointing. This invention is directed to systems and methods of imaging subsurface features of objects such as semiconductor devices. An illumination source may be directed toward a surface of an object comprising subsurface features, wherein the illumination from the source is directed at a first angle relative to the normal of the surface. The object may have a portion between the subsurface features and the surface, which has an index of refraction that is greater than the index of refraction of a surrounding medium that surrounds the object. An imaging device may be placed with an objective lens oriented substantially normal to the surface. The first angle may be larger than an acceptance angle of the objective lens.
T. S. Yeoh and N. A. Ives, “Isosurfacial Three-Dimensional Imaging System and Method,” U.S. Patent No. 8,217,937, July 2012.
Isosurfacial reconstruction methods reconstruct exterior surfaces of objects. However, a limitation of the isosurfacial technique is the lack of information of interior surfaces underneath exterior surfaces and exterior structures. This invention is directed to a three-dimensional isosurfacial imaging system and method for imaging objects that may have obscure interior surfaces hidden from exterior views. The system captures a series of tilt images that are used to reconstruct an isosurface of the object that is a threedimensional model image. The system then processes the series of tilt images using enhanced tomographic computations. The system can apply a special case in computeraided tomography that assumes complete transmission or complete absorption in order to compute the density micrograph.
F. Lorenzelli, “Signal Separator,” U.S. Patent No. 8,218,692, July 2012.
Techniques modifying transmitted signals to aid subsequent separation are the workhorses of modern-day communications, and it is their improvement that has dominated signal separation research and development. This invention relates to a device and process for separating digital signals embedded in a single received signal. The signal separation device and method of the invention include embodiments for separating uncoordinated cochannel signals of comparable power from a single received signal impaired by intersymbol interference, mutual interference, and additive noise. The method comprises the following steps: implementing an initial channel estimator, a blind maximum likelihood symbol detector, and a least-squares channel estimator in one or more digital processors; converting the received signal in an analog-to-digital converter, the sample rate of the converter exceeding the symbol rate by a factor greater than or equal to two; utilizing the initial channel estimator to make an initial set of channel estimates from the converted received signal; producing a data block by decimating the converted received signal; detecting symbols from the data block in a multisignal trellis of the maximum likelihood symbol detector using the most recent channel estimates; utilizing the least-squares channel estimator to make another set of channel estimates from the detected symbols; returning to the detecting step if the channel estimates have not converged; comparing the trellis end survivors’ metrics to determine if the detected symbols should be accepted; returning to the first utilizing step and revising the initial channel state information if the detected symbols are not accepted; and accepting the detected symbols and returning to the producing step if data remains.
J. K. Fuller, “Stereolithographic Rocket Motor Manufacturing Method,” U.S. Patent No. 8,225,507, July 2012.
Hybrid rocket motors use reactants of different physical phase states, usually a solid fuel such as rubber and a gaseous oxidizer such as nitrous oxide. While hybrid motors do not generally deliver the performance of liquid motors, they are safer and simpler to build and operate. Ideally, hybrid motors can have very good performance, but the realworld problems of maintaining an optimal oxidizer-to-fuel ratio and slow-burning fuels have limited their use to niche applications. This invention is directed to a hybrid rocket motor, including a fuel grain, that is created by printing a fuel material using rapid-prototyping techniques. A grain can be manufactured by photopolymerizing the solid fuel in a stereolithography rapid-prototyping type machine. Fuel grains made with rapid-prototyping techniques can be made of almost any shape. These grains can have improved performance by including port shapes and features that promote mixing and increase the amount of burning surface. Many of these port shapes could not be produced with traditional fabrication techniques.
R. P. Welle, “Phase-Change Valve Apparatuses,” U.S. Patent No. 8,240,336, August 2012.
Developments in miniaturization and large-scale integration in fluidics have led to the concept of creating an entire chemistry or biology laboratory on integrated microfluidic devices. However, producing reliable valves has proven to be problematic with these devices. Thus, there has remained a need for a bistable phase-change valve that can remain in either an open or closed position, and in which there is a very low probability of phase-change material being lost from the valve. This invention relates generally to valves for controlling fluid flow and, in particular, to valves for microfluidic devices. The invention is an electrically actuated bistable valve (e.g., microvalve) that uses a phase-change control fluid to alternately block and unblock the flow of a working fluid through the valve. The control fluid is introduced from a side channel and is pumped into or out of a main flow channel when the control fluid is in a liquid state. The valve apparatus includes the following elements: a substrate, a main flow channel, a control channel, a biphase material within the control channel, a heating element adjacent the control channel and the junction, and a pumping mechanism.
N. A. Ives, C. Suen, M. S. Leung, et al., “Adaptive Membrane Shape Deformation System,” U.S. Patent No. 8,244,066, August 2012.
The use of a lightweight antenna system is a desirable goal for space-based communication systems. A system that uses a lightweight polymeric material configured as a large sheet that may be greater than thirty meters in diameter has been proposed as a suitable candidate for such applications. However, there is a need to shape and maintain the sheet to reflect directed signals to act as an antenna. This invention is directed to a method for determining the shape of a flexible membrane and deforming a flexible deployable membrane. The method first captures three-dimensional shape data of a membrane that may be a flexible, deployable, space-based adaptive membrane antenna, and then determines the shape of the membrane. The determined membrane shape is compared to a desired shape and altered by actuation so that the membrane shape is deformed into the desired shape. The method can be applied to a system for maintaining the shape of the membrane to a desired shape. The system and method would include image capturing, image data processing, and activation beams for deforming the membrane shape into the desired shape.
R. P. Welle, “Microfluidic Devices with Separable Actuation and Fluid-Bearing Modules,” U.S. Patent No. 8,245,731, August 2012.
A microfluidic device should be fully capable of manipulating multiple fluids, which includes a number of functions such as storage, transport, heating, cooling, and mixing. Although all these functions have been demonstrated with varying degrees of success on microfluidic devices, valves and pumps have typically been complex devices that are difficult to manufacture. Unfortunately, this leads to high fabrication costs, which generally make it impractical to manufacture the devices to be disposable. Thus, a need has existed for a microfluidic device that is capable of performing various manipulations on fluids while also being manufacturable in a manner suitable for the devices to be disposable. This invention is a microfluidic device that is provided by two operatively interfaced modules, namely a fluid-bearing module and an actuator module. The fluidbearing module incorporates fluid transport and containment elements as well as other elements that may come into contact with fluids. The actuator module incorporates actuation mechanisms for fluid transport and control. The two modules are brought together into contact for use. The modules are detachably secured to each other, thereby allowing the fluid-bearing module to be separated from the actuator module and disposed of. On the other hand, the actuator module is reusable with another fluid-bearing module, eliminating in many instances the possibility of cross-contamination between fluids in the two fluid-bearing modules.
M. J. Lange, “High Power Waveguide Polarizer with Broad Bandwidth and Low Loss, and Methods of Making and Using Same,” U.S. Patent No. 8,248,178, August 2012.
Guided-wave polarizer technology converts a circularly polarized wave into a linear-polarized wave while maintaining orthogonality of the two possible senses of each polarized wave. However, prior art polarizers suffer from a number of deficiencies, including low bandwidth, high loss, low power-handling capability, and large size. This invention provides a compact waveguide polarizer that includes a hollow waveguide body and at least one ridge disposed along the interior of the waveguide body. Each ridge includes on its upper surface a plurality of spaced projections (e.g., cylindrical or rectangular posts) or serrations. The ridges and spaced projections together produce a broadband differential phase shift between two orthogonal modes propagating through the waveguide body. Specifically, the spaced projections provide a small capacitive reactance that offsets the inductive loading of the lower portions of the ridges. As a result, a mode propagating parallel to the ridges accumulates a phase delay relative to a mode propagating orthogonal to the ridges that is substantially independent of wavelength over a relatively wide bandwidth. The differential phase delay may easily be tuned by adjusting the length of the projections. The bandwidth of the polarizer may be enhanced by configuring the projections such that they are narrower than the ridges on which they are disposed. Additionally, the polarizers may be inexpensively fabricated, are compact, have no dielectric losses, may accept high power fields, and may be used in a wide variety of environmental conditions.
M. P. Ferringer, R. S. Clifton, and T. G. Thompson, “Systems and Methods for Parallel Processing Optimization for an Evolutionary Algorithm,” U.S. Patent No. 8,255,344, August 2012.
The goal of multiple-objective optimization is to maximize or minimize multiple measures of performance simultaneously while maintaining a diverse set of Pareto-optimal solutions. Classical multiple-objective optimization techniques are advantageous if the decision maker has some prior knowledge of the relative importance of each objective. Because classical methods reduce the multiple-objective problem to a single objective, convergence proofs exist assuming traditional techniques are employed. But despite these advantages, real-world problems, such as satellite constellation design optimization, challenge the effectiveness of classical methods. According to this invention, the systems and methods for parallel-processing optimization may include the following: receiving an initial population of parent chromosome data structures; selecting pairs of parent chromosome data structures; applying at least one evolutionary operator to the genes of the selected pairs to generate a plurality of child chromosome data structures; allocating the generated plurality of child chromosome structures to a plurality of slave processors; receiving objective function values for a portion of the plurality of allocated child chromosome data structures; merging the parent chromosome data structures with the received portion of the child chromosome data structures; and identifying a portion of the merged set of chromosome data structures as an elite set of chromosome data structures.
R. B. Dybdal, F. Lorenzelli, and S. J. Curry, “Methods and Systems for Increased Communication Throughput,” U.S. Patent No. 8,259,857, September 2012.
Various technical and economic factors have led to a desire to increase communication throughput within a given frequency bandwidth. One approach, for example, utilizes higher-order signal modulation formats such as eightphase shift keying and quadrature amplitude modulation to obtain greater bandwidth efficiency. Such modulation formats maximize the data transmitted in a given bandwidth, resulting in increased bandwidth efficiency. But one limitation of higher-order modulation is increased stringency on transmitter linearity resulting in transmitter power backoff requirements that reduce signal power for receiver detection and prompt the development of linearizers to allow operation closer to transmitter-saturated output levels. This invention is directed to systems and methods that use signal processing techniques to allow the frequency bandwidth to be shared among two or more independent data streams as a means to increase communication throughput. This invention allows the separation of the independent data streams from a composite signal comprised of the multiple independent data streams negating what would normally be unacceptable levels of cochannel interference or other interference for conventional receiving systems. In this way, multiple signal components may partially or completely share the same frequency bandwidth by applying signal separation techniques to obtain acceptable communication performance for each of the multiple signals. Several applications described in the patent describe potential increases in communication throughput that are achieved by applying signal processing techniques to a composite signal to communicate multiple independent data streams without the constraint imposed by passive design techniques to isolate the individual signal components.
J. Y. Kim, “Systems and Methods for Concurrently Emulating Multiple Channel Impairments,” U.S. Patent No. 8,265,921, September 2012
Wireless communications links are sometimes characterized by relatively high bit error rates, large delay-bandwidth products, variable round-trip times, asymmetric channels, and impairments caused by various expected and unexpected events such as weather, fading, blockage, or jamming. In order to test the functionality and performance of next-generation wireless networks, it is important to have the ability to emulate communication applications in real time over communications links with similar characteristics. Thus, there is a need for systems and methods for concurrently emulating multiple channel impairments. This invention describes a multichannel emulator system. The system may include a memory that stores a plurality of channel impairment profiles, where each channel impairment profile corresponds to a respective channel impairment type, a real-time clock that generates timing data, and a processor in communication with the memory and the real time clock. The processor may be configured to: receive a selection of two or more of the plurality of channel impairment profiles; generate a composite impairment profile by combining the selected two or more channel profiles, specifying time-variant impairments, or reflecting a combination of the respective impairment types of the selected channel profiles; and apply the time-variant impairments specified by the composite impairment profile to an input real-time data stream to generate an impaired real-time data stream, where a timing of the application of the timevariant impairments is based at least in part upon the timing data from the real-time clock.
M. T. Presley, “System and Method for Distributing Processing of a Single-Process Application Having First and Second Objects in a Network Having Local and Remote Processes,” U.S. Patent No. 8,266,201, September 2012
An object-oriented computer program contains interacting objects that carry out specific program logic. Single process programming techniques assume that all objects reside within the same process hosted on a single computer system. Distributed programming systems, on the other hand, are designed to support objects across multiple processes, usually hosted on separate computers. This invention overcomes the shortcomings of previous systems and methods of adapting single-process legacy systems and distributed applications by modifying object classes during load time. The systems and methods of this invention provide a computer method for distributive processing of an object on a plurality of processes. A computer system and method are provided for making modifications to run-time coding of object-oriented software that enables distributed execution. The method automatically modifies object class definitions as the objects are loaded into the executing process. More particularly, the code modifications cause instances of the classes to interact with a distributed run-time system that allows all objects to be migrated between processes. Because the class definitions are modified at run time, a programmer does not need to add any code for application distribution. Thus, no programmer expertise in distributed systems is necessary, or any a priori knowledge of the program flow.