Bookmarks

Recent Publications, Papers, and Patents by the Aerospace Technical Staff

Publications and Papers

(September 2008–February 2009)

W. Ailor, "Moving Forward on Space Traffic Control," 3rd IAASS Conference "Building a Safer Space Together," p. 5 (Rome, Italy, 2008).

W. Ailor et al., "Requirements for Warning Aircraft of Reentering Debris," 3rd IAASS Conference "Building a Safer Space Together," p. 8 (Noordwijk, Netherlands, 2009).

M. J. Baxter, "Scenario Results of a Global Trends Model for Use With Aerospace Systems Combat Simulations," 2009 IEEE Aerospace Conference, p. 10 (Piscataway, NJ, 2009).

S. Berson and Yong Jin, "Effect of Mobility on Future Satellite Packet Networks Routing Protocols," 2009 IEEE Aerospace Conference, p. 6 (Piscataway, NJ, 2009).

R. M. Bloom, "Band-Limited 2-D Interpolation Using NUFFT," 2009 IEEE Aerospace Conference, p. 9 (Piscataway, NJ, 2009).

J. Camparo, M. Huang, and J. Coffer, "Transient CPT Signals Arising from Rapid Changes in Laser Polarization," 2008 IEEE International Frequency Control Symposium, pp. 661–664 (Piscataway, NJ, 2008).

J. C. Cardema, J. N. Tanzillo, S. Lee, and C. B. Dunbar, "Performance and Characterization Results of a Lasercom Testbed for the Pointing, Acquisition, and Tracking Subsystem of a Satellite-to-Satellite Laser Communications Link," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7091, p. 70910P (2008).

D. W. Chen, M. Birnbaum, P. M. Belden, T. S. Rose, and S. M. Beck, "Multiwatt Continuous-Wave and Q-Switched Er:YAG Lasers at 1645 nm: Performance Issues," Optics Letters, Vol. 34, No. 10, pp. 1501–1503 (May 2009).

H. Chen, S. S. Osofsky, et al., "Optical Distress Beacon for Space Use," 3rd IAASS Conference "Building a Safer Space Together," p. 7 (Noordwijk, Netherlands, 2009).

C. Clark, A. Chin, P. Karuza, D. Rumsey, and D. Hinkley, "CubeSat Communications Transceiver for Increased Data Throughput," 2009 IEEE Aerospace Conference, p. 5 (Piscataway, NJ, 2009).

W. L. Dimpfl et al., "Application of the Born-Mayer Potential with a Hard-Sphere Scattering Kernel to Rarefied Hyperthermal Gas Flow Modeling," AIP Conference Proceedings, Vol. 1084, pp. 323–328 (2008).

R. B. Dybdal, "Measuring 'Not So Big' Antennas," 2008 IEEE Antennas and Propagation Society International Symposium and USNC/URSI National Radio Science Meeting, p. 4 (Piscataway, NJ, 2008).

D. L. Emmons and R. E. Bitten, "Quantitative Approach to Independent Schedule Estimates of NASA Science Missions," 2009 IEEE Aerospace Conference, p. 8 (Piscataway, NJ, 2009).

T. Fan, V. S. Lin, G. H. Wang, and P. A. Dafesh, "Study of Signal Combining Methodologies for Future GPS Flexible Navigation Payload (Part II)," 2008 IEEE/ION Position, Location and Navigation Symposium – PLANS 2008, pp. 1079–1089 (May 2008).

J. S. Fant and R. G. Pettit IV, "Cost-Performance Tradeoff for Embedded Systems," Software Technologies for Embedded and Ubiquitous Systems. 6th IFIP WG 10.2 International Workshop, SEUS 2008, pp. 198–208 (Springer-Verlag, Berlin, 2008).

G. Fathi, P. Ionov, and S. M. Beck, "LIDAR Versus Satellite-Measured Optical Thickness of a Wildfire Aerosol," 2009 IEEE Aerospace Conference, p. 6 (Piscataway, NJ, 2009).

J. F. Fennell, J. L. Roeder, et al., "HEO Satellite Frame and Differential Charging and SCATHA Low-Level Frame Charging," IEEE Transactions on Plasma Science, Vol. 36, No. 5, pp. 2271–2279 (Oct. 2008).

J. S. George, R. Koga, et al., "Neutron Soft Errors in Xilinx FPGAs at Lawrence Berkeley National Laboratory," 2008 IEEE Radiation Effects Data Workshop, pp. 118–123 (Piscataway, NJ, 2008).

A. M. Gilbert et al., "Evidence for Powerful AGN Winds at High Redshift: Dynamics of Galactic Outflows in Radio Galaxies During the 'Quasar Era'," Astronomy & Astrophysics, Vol. 491, No. 2, pp. 407–424 (Nov. 2008).

H. Green, J. Hant, and D. Lanzinger, "Calculating Network Availability," 2009 IEEE Aerospace Conference, p. 11 (Piscataway, NJ, 2009).

D. R. Greer, S. Eslinger, D. X. Houston, and R. J. Adams, "Assessing Executability in Large Complex Programs," 2009 IEEE Aerospace Conference, p. 10 (Piscataway, NJ, 2009).

A. K. Gupta and A. Q. Tu, "Cost-Effective Allocation of NASA's Rocket Propulsion Test Assets," 2009 IEEE Aerospace Conference, p. 15 (Piscataway, NJ, 2009).

J. L. Hall, J. A. Hackwell, D. M. Tratt, D. W. Warren, and S. J. Young, "Space-Based Mineral and Gas Identification Using a High-Performance Thermal Infrared Imaging Spectrometer," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7082, p. 70820M (2008).

S. R. Halper and R. M. Villahermosa, "Modified Polymers for Contamination Sensing and Prevention of Optical and Space Systems," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7069, p. 70690C (2008).

H. Helvajian and S. W. Janson, eds., Small Satellites: Past, Present, and Future (AIAA and The Aerospace Press, El Segundo, CA, 2009).

J. Hicks et al., "A Game-Theoretic Framework for Interference Avoidance," IEEE Transactions on Communications, Vol. 57, No. 4, pp. 1087–1098 (April 2009).

J. K. Holmes and S. Raghavan, "The Mean Cycle Slip Time for First-, Second-, and Third-Order PLLs," 2009 IEEE Aerospace Conference, p. 8 (Piscataway, NJ, 2009).

D. Howell et al., "Spatial Nyquist Fidelity Method for Structural Models of Opto-Mechanical Systems," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7017, p. 70171A (2008).

M. A. Johnson, "From Engineering to System Engineering to System of Systems Engineering," 2008 World Automation Congress, p. 6 (Piscataway, NJ, 2008).

J. A. Kechichian, "Inclusion of Higher Order Harmonics in the Modeling of Optimal Low-Thrust Orbit Transfer," Journal of the Astronautical Sciences, Vol. 56, No. 1, pp. 41–70 (Jan. 2008).

J. A. Kechichian, "The Inclusion of the Higher Order J3 and J4 Zonal Harmonics in the Modeling of Optimal Low-Thrust Orbit Transfer," Advances in the Astronautical Sciences, pp.1497–1518 (2008).

R. M. Keller, C. Lee, M. Thomas, M. Presley, J. Seidel, R. Davis, J. Betser, et al., "Grid-Enabling a Vibroacoustic Analysis Toolkit," International Journal of High Performance Computing and Networking, Vol. 5, No. 3, pp. 168–178 (2008).

R. Koga, P. Yu, and J. George, "Single Event Effects and Total Dose Test Results for TI TLK2711 Transceiver," 2008 IEEE Radiation Effects Data Workshop, pp. 69–75 (Piscataway, NJ, 2008).

R. Kumar, D. A. Taggart, and A. Mathur, "Detailed Analysis of the Impact of the Distortion Due to Nonlinear Amplifiers on BER Performance," 2009 IEEE Aerospace Conference, p. 11 (Piscataway, NJ, 2009).

D. Kun et al., "A New Low-Cost CFAR Detector for Spectrum Sensing With Cognitive Radio Systems," 2009 IEEE Aerospace Conference, p. 8 (Piscataway, NJ, 2009).

R. Lacoe, M. Johnson, et al., "Angular Dependence of Single Event Sensitivity in Hardened Flip/Flop Designs," IEEE Transactions on Nuclear Science, Vol. 55, No. 6, pp. 3295–3301 (Dec. 2008).

R. C. Lacoe, "Improving Integrated Circuit Performance Through the Application of Hardness-by-Design Methodology," IEEE Transactions on Nuclear Science, Vol. 55, No. 4, pp. 1903–1925 (Aug. 2008).

R. C. Lacoe et al., "Multiple Bit Upsets and Error Mitigation in Ultra-Deep Submicron SRAMS," IEEE Transactions on Nuclear Science, Vol. 55, No. 6, pp. 3288–3294 (Dec. 2008).

C. Lee et al., "Standards-Based Computing Capabilities for Distributed Geospatial Applications," Computer, Vol. 41, No. 11, pp. 50–57 (Nov. 2008).

S. Li et al., "The Geodesic Dome Phased Array Antenna for Satellite Operations Support – Antenna Resource Management," 2007 IEEE Antennas and Propagation Society International Symposium, pp. 3161–3164 (Piscataway, NJ, 2008).

J. R. Lince, H. I. Kim, P. A. Bertrand, et al., "Tribochemistry and Wear Life Improvement in Liquid-Lubricated H-DLC-Coated Bearings," STAR, Vol. 45, No. 26 (Jan. 2008).

D. L. Liu and K. T. Luey, "Particulate Infiltration Into a Simulated Space Telescope," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7069, p. 706907 (2008).

K. T. Luey and D. J. Coleman, "Photochemical Processes in a Two-Component Molecular Contaminant Film," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 7069, p. 706903 (2008).

B. G. Marchand and C. J. Kobel, "Geometry of Optimal Coverage for Targets Against a Space Background Subject to Visibility Constraints," Advances in the Astronautical Sciences, pp. 2067–2086 (2008).

J. N. Martin, "Using Architecture Modeling to Assess the Societal Benefits of the Global Earth Observation System-of-Systems," IEEE Systems Journal, Vol. 2, No. 3, pp. 304–311 (Sept. 2008).

J. E. Mazur et al., "Composition and Spectral Properties of the 1 AU Quiet-Time Suprathermal Ion Population During Solar Cycle 23," Astrophysical Journal, Vol. 693, No. 2, pp. 1588–1600 (March 2009).

E. J. McDonald, E. Grayver, et al., "Hardware Accelerated Multi-channel Receiver," 2009 IEEE Aerospace Conference, p. 7 (Piscataway, NJ, 2009).

N. Muhammad et al., "Wideband Global SATCOM (WGS) Earth Terminal Interoperability Demonstrations," 2008 IEEE Military Communications Conference, p. 6 (Piscataway, NJ, 2008).

T. Mulligan, J. B. Blake, et al., "Unusual Observations During the December 2006 Solar Energetic Particle Events Within an Interplanetary Coronal Mass Ejection at 1 AU," AIP Conference Proceedings, Vol. 1039, pp. 162–167 (2008).

T. Mulligan, J. B. Blake, J. F. Mazur, et al., "Local and Nonlocal Geometry of Interplanetary Coronal Mass Ejections: Galactic Cosmic Ray (GCR) Short-Period Variations and Magnetic Field Modeling," Journal of Geophysical Research – Part A – Space Physics, Vol. 113, No. A10, p. A10102 (Oct. 2008).

E. A. Nguyen, W. S. Greenwell, and M. J. Hecht, "Using an Assurance Case to Support Independent Assessment of the Transition to a New GPS Ground Control System," 2008 IEEE International Conference on Dependable Systems & Networks With FTCS and DCC (DSN), pp. 102–107 (Piscataway, NJ, 2008).

T. Norton, K. Conner, R. Covington, H. Ngo, and C. Rink, "Development of Reprogrammable High Frame-Rate Detector Devices for Laser Communication Pointing, Acquisition and Tracking," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 6877, p. 68770N (2008).

N. U. Ogamba, "A Parametric Reliability Prediction Tool for Space Applications," 2009 Annual Reliability and Maintainability Symposium, p. 6 (Piscataway, NJ, 2009).

K. R. Olson, K. A. Folgner, and G. K. Ternet, "Effects of Vacuum-Ultraviolet Radiation on the Desorption of Molecular Contaminants," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7069, p. 706905 (2008).

J. W. Palko and J. R. Srour, "Amorphous Inclusions in Irradiated Silicon and Their Effects on Material and Device Properties," IEEE Transactions on Nuclear Science, Vol. 55, No. 6, pp. 2992–2999 (Dec. 2008).

I. A. Palusinski, P. D. Fuqua, J. D. Barrie, M. J. Meshishnek, J. M. Geis, et al., "Optical Reflector Materials Experiment-I (ORMatE-I) and ORMatE-II on Board MISSE," AIP Conference Proceedings, Vol. 1087, pp. 249–270 (2009).

R. G. Pettit IV, "Increasing Confidence in Concurrent Software Through Architectural Analysis," Reliable Software Technologies—Ada-Europe 2008. 13th Ada-Europe International Conference on Reliable Software Technologies, pp. 199–210 (Springer-Verlag, Berlin, 2008).

R. S. Prabhu and A. Arredondo, "Evaluating MIMO Systems With Multi-Polarized Antennas," 2009 IEEE Aerospace Conference, p. 8 (Piscataway, NJ, 2009).

R. S. Prabhu and E. Grayver, "Active Constellation Modification Techniques for OFDM PAR Reduction," 2009 IEEE Aerospace Conference, p. 8 (Piscataway, NJ, 2009).

N. Presser, G. Stupian, M. Leung, et al., "In Vitro Detection of Neural Activity With Vertically Grown Single Platinum Nanowire," 2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems, pp. 360–362 (Piscataway, NJ, 2009).

R. Reid, B. Gardner, and R. Bitten, "Use of Electronic Media for Inter-active Space Systems Education," IEEE Aerospace and Electronic Systems Magazine, Vol. 24, No. 2, pp. 34–43 (Feb. 2009).

D. N. Riley et al., "Mapping Rock-Forming Minerals at Daylight Pass, Death Valley National Park, California, Using SEBASS Thermal–Infrared Hyperspectral Image Data," 2008 IEEE International Geoscience and Remote Sensing Symposium, pp. 366–369 (Piscataway, NJ, 2008).

J. L. Roeder and J. F. Fennell, "Differential Charging of Satellite Surface Materials," IEEE Transactions on Plasma Science, Vol. 37, No. 1, pp. 281–289 (Jan. 2009).

T. S. Rose, G. C. Valley, et al., "Time-Gated Filter for Sideband Suppression," Optics Letters, Vol. 34, No. 7, pp. 869–871 (April 2009).

M. Ross, D. Toohey, M. Peinemann, and P. Ross, "Limits on the Space Launch Market Related to Stratospheric Ozone Depletion," Astro-politics, Vol. 7, No. 1, pp. 50–82 (March 2009).

R. J. Rudy, D. K. Lynch, S. Mazuk, C. C. Venturini, R. W. Russell, et al., "A New Spectroscopic and Interferometric Study of the Young Stellar Object V645 Cygni," Astronomy and Astrophysics, Vol. 498, No. 1, pp. 115–126 (2009).

R. Russel et al., "GRB 071003: Broadband Follow-Up Observations of a Very Bright Gamma-Ray Burst in a Galactic Halo," Astrophysical Journal, Vol. 688, No. 1, pp. 470–490 (Nov. 2008).

J. N. Schulman et al., "Scaling of High-Performance InAs/AlSb/GaSb Heterostructure Detectors for Millimeter-Wave and Submillimeter-Wave Sensing and Imaging," 2008 66th Annual Device Research Conference, pp. 123–124 (Piscataway, NJ, 2008).

G. Sefler, G. Valley, et al., "150 GS/s Real-Time Oscilloscope Using a Photonic Front End," 2008 International Topical Meeting on Microwave Photonics (MWP 2008) jointly held with the 2008 Asia-Pacific Microwave Photonics Conference (APMP), pp. 35–38 (Piscataway, NJ, 2008).

G. A. Sefler, G. C. Valley, et al., "Compensation Algorithm for Deterministic Phase Ripple," 2008 Conference on Lasers and Electro-Optics, p. 2 (Piscataway, NJ, 2008).

G. A. Sefler, G. C. Valley, et al., "Phase Ripple Correction: Theory and Application," Optics Letters, Vol. 33, No. 10, pp.1108–1110 (2008).

E. M. Sims, "The Department of Defense Space Test Program: Come Fly With Us," 2009 IEEE Aerospace Conference, p. 6 (Piscataway, NJ, 2009).

Y. Sin, N. Presser, B. Foran, N. Ives, and S. C. Moss, "Catastrophic Facet and Bulk Degradation in High Power Multi-Mode InGaAs Strained Quantum Well Single Emitters," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 7198, p. 12 (Jan. 2009).

Y. Sin, N. Presser, B. Foran, and S. C. Moss, "Degradation Processes in High Power Multi-Mode InGaAs Strained Quantum Well Lasers," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 7230, p. 12 (Jan. 2009).

K. Siri, M. Willhoff, K. A. Conner, and D. Q. Tran, "High-Voltage-Input, Low-Voltage-Output, Series-Connected Converters With Uniform Voltage Distribution," 2009 IEEE Aerospace Conference, p. 9 (Piscataway, NJ, 2009).

D. A. Taggart, R. Kumar, and S. Raghavan, "Nonlinear Amplifier Noise Product Ratio Modeling and Simulation," 2009 IEEE Aerospace Conference, p. 9 (Piscataway, NJ, 2009).

J. N. Tanzillo, C. B. Dunbar, et al., "Development of a Lasercom Test-bed for the Pointing, Acquisition, and Tracking Subsystem of Satellite-to-Satellite Laser Communications Link," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 6877, p. 687704 (2008).

K. N. Tarasov, E. J. McDonald, and E. Grayver, "Power Amplifier Digital Predistortion – Fixed or Adaptive?," 2008 IEEE Military Communications Conference, p. 7 (Piscataway, NJ, 2008).

D. P. Taylor and H. Helvajian, "Volume Plasmon Ejection of Ions in Pulsed Ultraviolet Laser Induced Desorption from Several Metals," Physical Review B (Condensed Matter and Materials Physics), Vol. 79, No. 7, p. 12 (Feb. 2009).

M. M. Tong, "Efficient Treatment of Gyroscopic Bodies in the Recursive Solution of Multibody Dynamics Equations," Journal of Computational and Nonlinear Dynamics, Vol. 3, No. 4, p. 041006–1–6 (Oct. 2008).

E. L. Valles, K. Tarasov, J. Roberson, E. Grayver, and K. King, "An -EMWIN and LRIT Software Receiver Using GNU Radio," 2009 IEEE Aerospace Conference, p. 11 (Piscataway, NJ, 2009).

R. M. Villahermosa et al., "Chemical Analysis of Silicone Outgassing," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7069, p. 706906 (2008).

R. M. Villahermosa, B. H. Weiller, S. Virji, and D. P. Taylor, "Managing Contamination-Enhanced Laser Induced Damage (CLID)," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 7069, p. 706908 (2008).

D. W. Warren, D. J. Gutierrez, and E. R. Keim, "Dyson Spectrometers for High-Performance Infrared Applications," Optical Engineering, Vol. 47, No. 10, p. 103601 (Oct. 2008).

D. W. Warren, D. J. Gutierrez, J. L. Hall, and E. R. Keim, "Dyson Spectrometers for Infrared Earth Remote Sensing," Proceedings of the SPIE – The International Society for Optical Engineering, Vol. 7082, p. 70820R–1–8 (2008).

J. Watson and K. Zondervan, "The Missile Defense Agency's Space Tracking and Surveillance System," Proceedings of the SPIE—The International Society for Optical Engineering, Vol. 7106, p. 710617 (Sept. 2008).

H. T. Yura et al., "Speckles and Their Dynamics for Structured Target Illumination: Optical Spatial Filtering Velocimetry," Journal of Optics A: Pure and Applied Optics, Vol. 11, No. 5, p. 054001 (May 2009).

H. T. Yura et al., "Statistics of Spatially Integrated Speckle Intensity Difference," Journal of the Optical Society of America A (Optics, Image Science and Vision), Vol. 26, No. 2, pp. 371–375 (Feb. 2009).

Patents

(September 2008–April 2009)

D. A. Ksienski, J. P. McKay, S. S. Osofsky, K. S. MacGowan, and G. M. Shaw, "Higher-Order Intermodulation Reduction Using Phase and Angle Smearing," U.S. Patent No. 7,420,508, Sept. 2008.

Multiple, simultaneous antenna beams required in communication systems are often achieved using active phased arrays. A common problem encountered in these systems is the generation of intermodulation product beams due to nonlinear effects. This patent describes a method for reducing intermodulation beams. It starts by identifying one or more higher-order intermodulation beams that need to be reduced and determining acceptable degradations for the fundamental beams associated with them. Next, phase and angle beam-smearing parameters are identified that would reduce the intermodulation beams with acceptable degradation to the fundamental beams. These parameters are then used to apply a beam-smearing phase distribution to an array along with a beam-steering distribution. This invention can be used for satellite antenna arrays or any application that generates multiple simultaneous beams in the presence of nonlinear effects.

H. S. Hou, "Merge and Split Discrete Cosine Block Transform Method," U.S. Patent No. 7,437,394, Oct. 2008.

Fast transform methods for the compression and decompression of data entail separating and combining data blocks in the transform domain and inversely transforming them back to the spatial or temporal domain. In the process, however, the quality of the transformed data is degraded. This invention is aimed at decreasing the degradation caused by the fast forward process. Input data in the temporal or spatial domain during either the split or merge radix-2 forward processing step first undergoes transform processing followed by combinational processing. In the split transform process, whole transformed data are split into two halves using combinational processing in the transform domain. In the merge transform process, these two halves are merged using combinational processing in the transform domain. The combinational processing enables true recursive splits and merges in the transform domain without data degradation.

G. L. Lui, K. Tsai, and M. K. Sue, "Automatic Gain Control 16-ary Quadrature Amplitude Modulation Subsystem," U.S. Patent No. 7,450,670, Nov. 2008.

In a digital data transmission system that uses amplitude and phase modulation, such as the 16-ary quadrature amplitude modulation (16-QAM), the performance of the receiver is essential. However, if the receiver is not catching the large signal-to-noise ratios accurately enough, communication is compromised. The invention concerns a baseband automatic-gain-control subsystem that tracks the amplitude of signals with large signal-to-noise ratios as a subset of all of the signals in the constellation space. This information helps determine the amount of automatic gain control needed to uniformly improve reception of all received signals. By averaging only the signals with large signal-to-noise ratios, a demodulator can provide automatic gain control up to 1.0 dB better than a demodulator that averages all of the amplitudes of all of the received signals. The technique can be implemented with only modest modifications to an error detector in a conventional design.

T. Nguyen, J. Yoh, A. Mathur, and G. Goo, "Random Walk Filter Timing Recovery Loop," U.S. Patent No. 7,469,026, Dec. 2008.

In a communication receiver, a received RF signal is tracked and demodulated to generate a baseband signal waveform that contains bit transitions to help the demodulator lock on to the data bit stream; however, channel noise can corrupt the bit transition timing and cause the demodulator to lose track of the bit stream. Timing recovery loops are used to track bit transitions and reacquire the bit stream, but most conventional algorithms are still subject to long reacquisition time and frequent bit timing lock drop in multipath environments. This invention uses a random-walk filter with a settable error threshold that allows for adaptive synchronization in the timing recovery loop. When the filter's lead/lag counter output exceeds the threshold, the estimated bit transition time can be adjusted, allowing for its continued synchronization to the signal waveform. As such, the random-walk filter continuously adjusts the estimated bit transition time to maintain an accurate bit timing lock. This timing recovery loop can be used with low-power technology and is applicable to a wide range of modulation schemes for enhanced mobile -communications.

A. O. Okorogu, "High Power Optical Fiber Laser Array Holographic Couplers," U.S. Patent No. 7,469,082, Dec. 2008.

Current methods of launching high-power pump or laser light into fibers can adversely affect the mechanical integrity, power requirements, and system complexity, which would require -redesigning the fiber coupling structure, especially for coupling an array of laser diodes. This patent describes a novel method of coupling high-power laser light or an array of laser diodes into double-clad Yb and co-doped Er-Yb fibers for much higher levels of light amplification. It is based on the application of mature volume holographic optical element (HOE) technology, which can be fabricated in any of the commercially available high-efficiency photosensitive holographic recording materials. This HOE coupler does not require mechanical etching of coupling structures or embedding of micromirrors within the fiber cladding. It consists of stripped double-clad fiber sandwiched between transmitting and reflecting HOEs. The device offers advantages over current coupling schemes, especially ease of coupling, high angular and spectral selectivity (filtering), high optical power (concentration), light weight, thin aspect (~15 mm), low cost, high coupling efficiency, insensitivity to misalignment, and simplicity of direct coupling into fibers with minimum perturbation of fiber structure and manufacturability. It has a unique advantage of being a truly universal coupling scheme for all types of inner cladding shapes, sizes, and designs.

W. E. Lillo, K. J. Scully, and C. D. Nealy, "Multitarget Tracking Antispoofing Receiver," U.S. Patent No. 7,471,238, Dec. 2008.

This GPS receiver improves tracking in the presence of jamming or spoofing signals by coupling the GPS signal with an inertial navigation system that has an inertial measurement unit (IMU). When it encounters an interfering signal, the receiver maintains track on the target signal by tracking the code phase, carrier frequency, and power. Conventional multitarget tracking algorithms are used to distinguish among the competing signals. When signal tracks have been sufficiently resolved, the tracking information is fed to a prefilter and ultimately to the navigation filter. The IMU information allows for a narrow gate for the true signal. The crossing of tracks can be anticipated and resolved without losing track on a desired object. The greater power of the spoofer is a distinguishing characteristic and actually hinders its ability to interfere. Therefore, the multitarget tracking receiver can maintain a lock on a target signal, even in the presence of crossover spoofing signals.

M. A. Zurbuchen, "Automated Sectioning Tomographic Measurement System," U.S. Patent No. 7,507,145, Mar. 2009.

There is frequently a need to image the internal structure of an object—particularly at the scale of 200 nm to 10 mm—to determine failure mechanisms. Typically, a sectioning approach is used in which successive layers are removed in very thin slices; however, this approach poses difficulties in terms of accuracy and resolution. This invention describes a tomographic measurement system that integrates the processes of grinding and polishing a 3-D cross section and imaging it in digital form so that it can be stored in a computer. The system includes a number of abrasive grinders, a wash station for washing and etching the object for improved imaging, an imaging station that captures both the object and a marker that indicates the depth of grinding, and a robot for moving the fixture between the grinder, washer, and imager. A simple edge-detection algorithm enables computer control software to recognize the marker reading in a given image; the marker can therefore be used to stop the automated serial sectioning at target depths. The system can process objects on scales as small as 2.5 nm.

R. B. Dybdal and D. Pidhayny, "Methods and Systems for Tracking Signals with Diverse Polarization Properties," U.S. Patent Nos. 7,518,551 and 7,551,134, Apr./June 2009.

Antennas are generally designed to receive radio frequency signals with a specified polarization, but in practice, the polarization of received signals does not always conform to the specified value. The resulting polarization mismatch reduces signal strength, degrading system sensitivity; in extreme cases, the antenna tracking performance can become unstable, resulting in a loss of antenna tracking and signal reception. This invention describes a system for antenna tracking that measures and processes orthogonally polarized signal components. The processing serves two objectives. The first is to minimize polarization mismatch loss, thereby preserving full system sensitivity. The second is to avoid unstable antenna tracking and the resulting signal loss while optimizing antenna tracking performance. The antenna tracking design operates in a closed-loop manner that can dynamically follow changes in the received signal's polarization values.

J. T. Dickey and T. T. Lam, "High Density Electronic Cooling Triangular Shaped Microchannel Device," U.S. Patent No. 7,523,780, Apr. 2009.

Cooling technology for microelectronic products is being pushed to the limit by the increasing number of components mounted on high-density electronic chips. This patent describes a pumped-fluid loop with triangular microchannels arranged in a sawtooth configuration. This orientation maximizes the absorption of thermal energy by the fluid and can increase the heat-transfer coefficient by 4.5 W/cm²/°C. The microchannels have a large heat conduction area that effectively spreads heat throughout the device, resulting in low surface temperatures. The triangular shape allows for a large number of microchannels to be packed together, thereby enabling a high flow rate of the pumped fluid. The sawtooth configuration allows for high heat conduction through an interstitial area, enabling heat to travel freely to the entire convective surface area. The reduced and uniform temperature serves to increase reliability and component life.

M. A. Rolenz, "Laser Communications Crosslink System," U.S. Patent No. 7,526,206, Apr. 2009.

Traditional satellite crosslinks can adversely increase the complexity and power requirements of a space system. This laser crosslink system mitigates these problems. A sigma-delta modulator converts an analog input to a binary data stream that is sent to a laser transmitter. The data stream is received by a laser receiver and sent to a digital filter that generates a digital output. Thus, the system enables direct laser modulation of binary signals. Because it combines the analog-to-digital conversion and transmission steps, the system requires fewer parts and power requirements than a comparable system based on phase-shift keying. The use of a sigma-delta modulator prior to transmission also reduces the roll-off requirements for anti-aliasing filters in the analog-to-digital converter, which in turn reduces manufacturing tolerances and required performance.

F. E. Livingston and H. Helvajian, "Pulse Modulation Laser Writing System," U.S. Patent No. 7,526,357, Apr. 2009.

Laser processing and micro/nanomachining of materials and components are generally limited by the relative lack of precision photon flux control, particularly when the samples are in motion or constructed of multiple heterogeneous materials. This pulse-modulated laser writing system overcomes this problem by enabling the position-synchronized delivery of discrete, preprogrammed laser pulse scripts to a substrate with high fidelity during patterning and motion sequences. The laser pulse scripts are synchronized with the motion-control file so that every laser-irradiated spot within the sample will receive exactly the photon dose and intensity pulse sequence necessary, despite the evolving material properties or changes in velocity of the sample. The laser processing platform is highly versatile and can seamlessly and dynamically merge a diverse array of other process scripts, including material type, surface topography, prior photon dose history, and the desired type of material processing, along with automated calibration routines and diagnostic tests. The laser technique can be readily applied to fundamental investigations of complex laser-material interaction phenomena, and the architecture can be easily integrated into laser-material processing schemes for commercial and industrial applications.

G. L. Lui and K. Tsai, "Quaternary Precoded Continuous Phase Modulation Soft Bit Metric Demodulator," U.S. Patent No. 7,529,323, May 2009.

A quaternary soft-bit metric (QSBM) demodulator uses the maximum-likelihood sequence estimation (MLSE) Viterbi algorithm to generate log-likelihood ratios. The demodulator can be used for precoded quaternary Gaussian minimum shift keying (GMSK) signals and, more generally, for precoded quaternary continuous phase modulation (CPM) signals. It is implemented as a streamlined MLSE Viterbi algorithm that requires no memory elements for storing the survivor path states. In a GMSK system, the bandwidth-time product of the Gaussian premodulation shaping filter is 1/3, the modulation index is 1/4, and the receiver uses three matched filters. The demodulator can be used either in a stand-alone uncoded CPM system or in a coded CPM system in conjunction with some forward error-correction scheme such as the classical rate-1/2 convolution code with MLSE Viterbi decoding. In the latter case, the demodulator can improve the signal-to-noise ratio by 3.0 decibels over hard-decision error-correction decoding.

A. O. Okorogu, "High Power Optical Fiber Laser Array Holographic Coupler Manufacturing Method," U.S. Patent No. 7,551,818, Apr. 2009.

This cost-effective method of manufacturing universal or versatile holographic optical element (HOE) couplers requires no mechanical etching or embedded micromirrors and offers easy mechanical coupling, insensitivity to misalignment of laser diodes, and high-angular and spectral filtering selectivity. The process entails simulating a laser diode or an array of diodes with varying divergence angles by placing a slit or slit array and/or an array of microlenses in the path of collimated object beams, which generate spherical wavefronts with divergence angles of various magnitudes. The position of the slits represents the lateral location of the laser diodes in the arrays that are to be coupled into the fiber. The separation of the slits is the exact separation distance of the intended diode in the fiber scheme. A computer controls the lateral position of each slit or microlens point and incrementally steps light from there to illuminate the holographic film plate where it intersects with a reference spherical beam. The intersection of the beams creates a varying fringe structure called a "chirped" grating. Creation of the chirped grating within the HOE increases the coupling efficiency of the laser diodes into a supported cladding mode of the fiber to greater than 90 percent. This would be impossible with any coupler that does not account for sources with varying divergence angles.

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