SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 1 - January 13, 2006
32 COMMUNICATIONS AND RADAR
Includes radar; radio, wire, and optical communications; land and global communications; communications theory.
For related information see also 04 Aircraft Communications and Navigation; and 17 Space Communications, Spacecraft Communications, Command and Tracking; for search and rescue, see 03 Air Transportation and Safety; and 16 Space Transportation and Safety.
20060001559 Federal Aviation Administration, Oklahoma City, OK, USA
Terminal Radar Approach Control: Measures of Voice Communications System Performance
Prinzo, O. Veronika; McClellan, Mark; October 2005; 23 pp.; In English; Original contains color illustrations Contract(s)/Grant(s): FAA-AM-B-03-HRR-516 Report No.(s): DOT/FAA/AM-05/19; No Copyright; Avail.: CASI: A03, Hardcopy
Effective communications in the National Airspace System (NAS) is an essential safety component of successful air travel. As the NAS migrates from its current ground infrastructure and voice communications system to one that encompasses both ground and airborne systems, digital data transmission may become the principal communication medium. As technological advances lead to innovations in communications system development, these emerging systems will be evaluated against the existing legacy system's performance parameters such as setup delay, voice streaming, pause duration, and message propagation.
The data presented here are but a first step in providing objective and quantifiable communications system performance metrics that may prove valuable to communication systems developers and personnel charged with evaluating, a certifying, and deploying the next generation of communications systems. The authors analyzed nearly 8,000 transmissions that represented the busiest air-ground communications from the five terminal radar approach control facilities with the highest number of operations in the contiguous USA.
Typically, setup delays lasted 81 ms, voice streaming 2568 ms, pause duration 127 ms, and message propagation 73 ms for a total of 2849 ms per transmission. On average, transmissions were separated by 1736 ms of silence. Disruptions to efficient information transfer can result from blocked, stepped-on, and clipped transmissions--but they are rare events and occurred in only 1.16% of the sampled transmissions.
A comparison between aircraft with and without disruptions revealed that when a disruption was present, an average of 14.54 messages were transmitted, compared with an average of 9.90 messages when no disruption was present. Even so, there appears to be some type of detection mechanism in place to alert the controller to the presence of blocked transmissions. The source is of this detection system is unclear; however, systems developers may want to exploit and expand this capability to include stepped-on and clipped transmissions. Author
Air Traffic Control; Radar Approach Control; Terminal Guidance; Voice Communication; National Airspace System
20060001595 Naval Postgraduate School, Monterey, CA, USA
Passive Multipath Target Tracking in Inhomogeneous Acoustic Medium
Shefi, Amnon; Therrien, CharlesW.; Kirk, Donald E.; Saez, Rigoberto; Friedlander, Benjamin; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 12.8.1 - 12.8.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
A method is presented for acoustic passive multipath target tracking in the ocean. The method accounts for the inhomogenuity of the medium by integration of a prefilter into the tracking algorithm. The prefilter uses the output of an eigenray acoustic model computed over a two dimensional (2-D) grid of possible target positions (depth, range). The function is inverted and interpolated to form a transfer function from propagation time delay differences to range and depth. A three dimensional (3-D) maneuvering target estimator is used and its performance is evaluated. The results demonstrate the strong effects of the medium on the tracking concept. Author
Multipath Transmission; Acoustics; Interpolation; Tracking (Position); Transfer Functions; Algorithms; Depth
20060001614 Florida Univ., Gainesville, FL, USA
Co-Channel Speech Separation
Childers, D. G.; Lee, C. K.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 6.4.1 - 6.4.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
A new algorithm is proposed to solve the problem of separating two voices which co-exist on a single channel.
This algorithm produces an initial estimate of the speech spectrum for each talker, and then employs multisignal minimum-crossentropy spectral analysis to improve the initial spectral estimates by accounting for the characteristics of the known composite speech signal.
Results of listening tests and spectral distortion comparisons show that the proposed algorithm can recover the desired speech with better intelligibility than other speech separation techniques. Author
Distortion; Intelligibility; Speech
20060001634 Stanford Univ., Stanford, CA, USA
A Fast Transversal Filter for Adaptive Line Enhancement
Slock, D. T. M.; Cioffi, J. M.; Kailath, T.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 11.7.1-11.7.4; In English; See also 20060001583 Contract(s)/Grant(s): DAAG29-85-K-0048; AF83-0228; N00014-85-K-0550; Copyright; Avail.: Other Sources
The important problem of Adaptive Line Enhancing (ALE) is addressed in this paper. Its solution involves an Adaptive Notch Filter (ANF)using a minimal parameter constrained infinite impulse response (IIR) model in conjunction with the Recursive Prediction Error Method (RPEM). A Fast Transversal Filter (FTF) algorithm for the adaptive RLS-type updating of the linear phase filter is presented. Author (revised)
Adaptive Filters; Linear Filters; Mathematical Models
20060001659 Minnesota Univ., Minneapolis, MN, USA
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Incorporated Robustness in Narrowband Signal Subspace Spatial Spectral Estimators
Buckley, Kevin M.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 2.7.1 - 2.7.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
Signal subspace spectral estimation algorithms are, by design, highly sensitive to differences between assumed source observation models and actual source observations. In spatial spectral estimation, where observations are derived from different array elements and are a function of various source propagation and observation parameters, accurate source modeling is often not possible. As a result, when incorrect values of model parameters are assumed, signal subspace algorithm performance is degraded. In this paper, an approach for incorporating robustness to assumed model parameter values is investigated. The approach is based on: 1) a representation of rank-1 sources in an low-rank subspace; and 2) a signal subspace projection algorithm suggested by Schrnidt. In addition to providing robustness to certain types of parameter variations, the approach provides a computationally efficient way of searching through some multidimensional parameter spaces. Author
Narrowband; Robustness (Mathematics); Signals
20060001674 California Univ., Los Angeles, CA, USA
Adaptive Filtering Without a Desired Signal
Griffiths, Lloyd J.; Rude, Michael J.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 4.1.1-4.1.4; In English; See also 20060001583 Contract(s)/Grant(s): 4901EP 26795; Copyright; Avail.: Other Sources
In least-squares estimation problems, a desired signal d(n) is estimated using a linear combination of L successive data samples, [x (n), x (n-1) ..... z (n-L +1)]. The weight set W(sub opt) which minimizes the mean-square error between d(n) and the estimate is given by the product of the inverse data covariance matrix and the cross-correlation between the data vector and the desired signal, i.e. the P-vector. For those cases in which time samples of both the desired and data vector signals are available, a variety of adaptive methods have been proposed which will guarantee that an iterative weight vector W(sub a) (n) converges (in some sense) to the optimal solution. Two which have been extensively studied are the recursive least-squares (RLS) method and the LMS gradient approximation approach. Author
Covariance; Adaptive Filters; Matrices (Mathematics); Estimating; Mean Square Values
20060001684 Hong Kong Univ., Hong Kong
A Second Generation Silicon Compiler for Bit-Serial Signal Processing Architecture
Cheung, Y. S.; Leung, S. C.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 487-490; In English; See also 20060001583; Copyright; Avail.: Other Sources
This paper describes a silicon compiler for hit serial signal processing architecture. Some of its features are inherited from the FIRST compiler. A description language is designed to provide a higher-level abstraction and concise specification of physical systems. The compiler automatically computes all the necessary timing requirements for bit-serial time-alignment and generates the necessary control networks. Two examples, a second order autorecursive filter and a fast Fourier transform processor are used as illustrations of the features provided by the compiler. Author
Silicon Transistors; Signal Processing; Compilers
20060001695 IBM Federal Systems Div., Manassas, VA, USA
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True Angle Estimation from a Line Array Using Time-Delay Estimates Over a Known Rotation
Johnson, G. W.; Modugno, E. J.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 12.2.1-12.2.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
The passive determination of conical-bearing angle from a line array is routinely accomplished by estimating the differences in the arrival times of an acoustic wavefront along the aperture.
The conversion from a conical bearing angle to a true bearing (azimuth) angle requires an estimate of the depression/elevation angle of the source.
This paper shows that the observation of time-delay estimates over a known rotation of the line array is an effective procedure for true angle estimation.
Theoretical performance analysis and Monte Carlo simulation results are presented for a broad optimal algorithm which utilizes all of the available time delay information over the array rotation.
This work has significant implications regarding source localization from line arrays. Author
Elevation Angle; Rotation; Time Lag; Algorithms; Arrays
20060001711 Tata Inst. of Fundamental Research, Bombay, India
A Speech Enhancement Method Based on Kalman Filtering
Paliwal, K. K.; Basu, Anjan; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 6.3.1-6.3.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
In this paper, the problem of speech enhancement when only corrupted speech signal is available for processing is considered. For this, the Kalman filtering method is studied and compared with the Wiener filtering method. Its performance is found to be significantly better than theWiener filtering method. A delayed-Kalman filtering method is also proposed which improves the speech enhancement performance of Kalman filter further. Author
Kalman Filters; Wiener Filtering; Words (Language)
20060001715 Advanced Decision Systems, Mountain View, CA, USA
Knowledge Based Object Detection Using SAR Images
Wang, David L.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 7.16.1-7.16.4; In English; See also 20060001583 Contract(s)/Grant(s): DACA86-C-0010; Copyright; Avail.: Other Sources
One of the basic research problems in analyzing synthetic aperture radar (SAR) imagery is the detection of man-made objects. This paper presents a detection paradigm composed of an adaptive segmentation algorithm based on a priori knowledge of objects followed by a top-down hierarchical detection process that generates and evaluates object hypotheses. At the end of this process the most likely hypothesis for the object is selected. The hierarchical structure allows the use of shadow information and inter-object relationships to improve performance over that of a statistical detector based only on the properties of individual objects. Author
Radar Imagery; Synthetic Aperture Radar; Knowledge Based Systems
20060001724 Exxon Production Research Company, Houston, TX, USA
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Fitting Noncausal Autoregressive Signal Plus Noise Models to Noisy Non-Gaussian Linear Processes
Tugnait, Jitendra K.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 324-327; In English; See also 20060001583; Copyright; Avail.: Other Sources
The problem of estimating parameters of a noncausal autoregressive signal from noisy observations is considered. The signal is assumed to be non-Gaussian. The measurement noise is allowed to be non-Gaussian. Two techniques that use both autocorrelations and third-order autocumulants of the data are presented for parameter estimation. Strong consistency of the proposed techniques is proved under certain sufficient conditions. Knowledge of the probability distribution of the driving noise is not required. Simulation examples are presented to illustrate the two methods. The problem of model order selection is also addressed. Author
Parameter Identification; Signal Processing; Autoregressive Processes; Noise Spectra
20060001727 Northeastern Univ., Boston, MA, USA
Discrete All-Pole Modeling for Voiced Speech
El-Jaroudi, Amro; Makhoul, John; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '87); Volume 1; 1987, pp. 8.9.1 - 8.9.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
A new method is introduced for parametric modeling of spectral envelopes when only a discrete set of spectral points is given. This method, which we call Discrete All-Pole (DAP) modeling, uses a discrete version of the Itakura-Saito distortion measure as its error criterion. DAP overcomes the limitations of linear prediction and produces better fitting spectral envelopes for spectra that are representable by a relatively small discrete set of values, such as in voiced speech. The method is especially relevant when the pitch frequency is high as in female speech. Author
Discrete Functions; Frequencies; Voice Communication
20060001785 Connecticut Univ., Storrs, CT USA
Analytic Model Driven Organizational Design and Experimentation in Adaptive Command and Control
Levchuk, Yuri N.; Pattipati, Krishna R.; Kleinman, David L.; Jan. 1, 2005; 12 pp.; In English Contract(s)/Grant(s): N00014-93-1-0793 Report No.(s): AD-A440207; No Copyright; Avail.: Defense Technical Information Center (DTIC)
The purpose of this paper is to present a methodology for the design of experiments to examine the organizational behavior of command and control teams operating in a complex mission environment. This methodology can be used to design an executable model for human-in-the-loop, model-based experiments that provide the necessary empirical components for current and future research in adaptive C2 architectures.
The authors discuss a joint model of a mission and an organization to specify the structure of the mission, organizational constraints and processes, and the requirements for an organizational design. Their methodology illustrates the underlying principles that guide the design of organizations. The paper provides an analytical starting point for model-based experimental research on adaptive architectures. In coordination with companion empirical efforts, it seeks to integrate optimization, modeling, and simulation-based research efforts with psychology-based and experimental activities to conduct humans-in-the-loop, model-driven experiments studying adaptive C2 architectures.
The proposed models drive the formulation of hypotheses, the determination of key variables and their values, and the prediction of organizational performance and the processes of adaptation. The generated measures of organizational performance provide a basis for post-experimental model-data comparison. In addition, the implementation of the design procedure in software allows one to estimate the optimal experimental conditions to test a specific hypothesis. The empirical findings will assist a modeler in identifying new design parameters affecting organizational performance to further study the dependency of organizational performance on the mission structure and on organizational design. DTIC
Adaptation; Adaptive Control; Command and Control; Experiment Design; Mathematical Models; Models; Organizations
20060001838 Aptima, Inc., Woburn, MA USA
Building Adaptive Organizations: A Bridge from Basic Research to Operational Exercises
Hess, Kathleen P.; Hess, Stephen M.; Kemple,William G.; Hocevar, Susan P.; Entin, Elliot E.; Hutchins, Susan G.; Kleinman, David L.; Serfaty, Daniel; Jan. 1, 2005; 15 pp.; In English; Original contains color illustrations Contract(s)/Grant(s): N00014-99-C-0255 Report No.(s): AD-A440347; No Copyright; Avail.: Defense Technical Information Center (DTIC)
Realizing the benefits of network-centric warfare -- in terms of improved access to high-quality information, speed of command, and dominant application of forces -- will require a synergy among three dimensions of change: technology, force organization, and team processes. To achieve the potential advantages of new technological capabilities requires that the military reexamine old rules of business and force-structures and recast them in ways that allow for increased flexibility and application of force where and when it is required. Experiments and exercises designed to explore alternative structures, processes, and the impacts of information technologies are complex, precisely because they force change in all three dimensions. The challenge of assessing the impacts of these changes in terms of individual, team, and overall organizational performance, are great. This paper describes an approach to dealing with the complexity of assessment described above through the application of 'bridge' experiments that start with a blend of modeling and experimentation in the laboratory -- to thoroughly explore core concepts and test new assessment ideas under controlled conditions -- and scale to meet the challenges of field-level performance assessment by emphasizing those issues that proved to be performance drivers in the laboratory. DTIC
Command and Control; Evaluation; Organizations; Research; System Effectiveness; War Games; Warfare
20060001872 Maryland Univ., Baltimore, MD USA
ENcentive: A Framework for Intelligent Marketing in Mobile Peer-To-Peer Environments
Ratsimor, Olga; Finin, Tim; Joshi, Anupam; Yesha, Yelena; Jan. 1, 2005; 9 pp.; In English; Original contains color illustrations Contract(s)/Grant(s): F30602-00-2-0591 Report No.(s): AD-A440420; No Copyright; Avail.: Defense Technical Information Center (DTIC)
In recent years, the growth of Mobile Computing, Electronic Commerce and Mobile Electronic Commerce has created a new concept of Mobile Electronic Marketing. New marketing models are being developed and used to target mobile users. A mobile environment introduces new challenges that need to be overcome by these marketing models in order to be successful and effective. This paper proposes a framework, called eNcentive, which addresses many of the issues that are characteristic of mobile environments. eNcentive facilitates peer-to-peer electronic marketing in mobile ad hoc environments. Our framework employs an intelligent marketing scheme, by providing users the capability to collect information like sales promotions and discounts. Users can propagate this marketing information to other users in the network. Participating users benefit from such circulation since businesses that originally created the promotions reward the active distributors with additional promotions and other compensations. DTIC
Electronic Commerce; Marketing; Wireless Communication
20060001929 Alphatech, Inc., Burlington, MA USA
Optimized Command and Control Architectures for Improved Process and Performance
Entin, Elliot E.; Jan. 1, 2005; 10 pp.; In English; Original contains color illustrations Contract(s)/Grant(s): N00014-95-C-0125 Report No.(s): AD-A440605; No Copyright; Avail.: CASI: A02, Hardcopy
Evidence in a recent study contrasting team performance in traditional unoptimized architectures to performance in non-traditional optimized architectures showed higher performance in the traditional unoptimized architectures. This was the case despite the fact that the optimization process matched the architecture to the mission and reduced internodal coordination. The experimenters surmised that unfamiliarity with the non-traditional optimized architectures was an important reason for the lower performance in the optimized architectures. The present experiment was conducted to improve upon the design used in the previous experiment so that a valid comparison could be made between a traditional non-optimized architecture and a nontraditional optimized one. As expected, once teams were afforded sufficient training with the non-traditional optimized architecture, they performed higher with it than with a traditional unoptimized architecture. The results provide support for a simple model linking architecture type through team processes to performance. DTIC
Command and Control; Communication Networks; Optimization
20060001931 Aptima, Inc., Woburn, MA USA
Adaptive Architectures for Command and Control: Toward an Empirical Evaluation of Organizational Congruence and Adaptation
Diedrich, Frederick J.; Hocevar, Susan P.; Entin, Elliot E.; Hutchins, Susan G.; Kemple, William G.; Kleinman, Davied L.; Apr. 19, 2005; 15 pp.; In English; Original contains color illustrations Contract(s)/Grant(s): N00014-99-C-0255 Report No.(s): AD-A440624; No Copyright; Avail.: CASI: A03, Hardcopy
How do teams cope with a misalignment between their organizational structures and mission requirements? Through a series of empirical and modeling efforts, our long-term goal is to understand the nature of organizational congruence, and to predict and measure the effects of a lack of congruence on the behaviors of organizations as they strive to adapt. In this paper, we present a series of lessons learned based on a pilot experiment in which we explored the performance of two organizations (functional and divisional) performing a single mission, which in this case, was not designed to favor a particular organization. The lessons learned here suggest a variety of empirical strategies to further our investigations, including measures of performance, rigorous attention to team and mission definitions, and precise planning of training structure. Our findings suggest that each of these factors has the potential to profoundly influence the results, reflecting the multiple factors that shape team performance. DTIC
Command and Control; Congruences; Organizations
20060002073 National Inst. of Information and Communications Technology, Tokyo, Japan
Journal of the National Institute of Information and Communications Technology. Special Issue on Information Security, Volume 52, Nos. 1/2
Takahashi, Tetsuo, Editor; Tawara, Yasuo, Editor; Watanabe, Katsuya, Editor; Tomita, Fumihiko, Editor; Kurihara, Noriyuki, Editor; Okada, Kazunori, Editor; March/June 2005; 313 pp.; In English; See also 20060002074 - 20060002101; Original contains color and black and white illustrations; Copyright; Avail.: Other Sources
Contents include the following: 1. Researches on Information Security in NICT. Technologies for Security of the Internet. Study on Process Model for Internet Risk Analysis. Design and Phase-1 Development of Secure Overlay Networks. A Development of Experimental Environments 'SIOS' and 'VM Nebula' for Reproducing Internet Security Incidents. Buffer-Overflow Detection in C Program by Static Detection. Efficient Traceback Method for Detecting Illegal Access. Log Management System Based on Distributed Database Using P2P Network. The Mathematics Models and an Actual Proof Experiment for IP Traceback System. Detecting Unknown Computer Viruses -A New Approach. Countermeasures Against Information Leakage. Subgroup Membership Problem and Its Applications to Information Security. A Functional Cryptosystem Using a Group Action. A Generalized Harley Algorithm for Genus Two Hyperelliptic Curves. An Expansion Algorithm for Higher Order Differential Cryptanalysis of Secret Key Ciphers. A Study on Higher Order Differential Cryptanalysis of 64 Bit Block Cipher KASUMI. On Multi Rounds Elimination Method for Higher Order Differential Cryptanalysis. Error Detection and Authentication in Quantum Key Distribution. Information Hiding on Digital Documents by Adjustment of New-line Positions.. CASI
Computer Information Security; Computer Viruses; Management Systems; Information Systems
20060002080 National Inst. of Information and Communications Technology, Japan
A Functional Cryptosystem Using a Group Action
Yamamura, Akihiro; Journal of the National Institute of Information and Communications Technology. Special Issue on Information Security, Volume 52, Nos. 1/2; March/June 2005, pp. 101-110; In English; See also 20060002073; Copyright; Avail.: Other Sources
The main purpose of this paper is to examine applications of group cryptography. We construct a backward deterministic system employing the action of the modular group on the upper half plane and the amalgamated free product structure of the group. We invent a geometrical algorithm that finds the normal form of an element of the modular group effectively. This algorithm makes our backward deterministic system tractable. Using the backward deterministic system, we invent a public-key cryptosystem in terms of a functional cryp system. Author
Algorithms; Cryptography; Group Theory; Modularity
20060002099 National Inst. of Information and Communications Technology, Tokyo, Japan
Limiting the Holding Time in Mobile Cellular Phone Systems During Disasters
Okada, Kazunori; Journal of the National Institute of Information and Communications Technology. Special Issue on Information Security, Volume 52, Nos. 1/2; March/June 2005, pp. 289-299; In English; See also 20060002073; Copyright; Avail.: Other Sources
Call demand suddenly and greatly increases during major disasters, because people want to check on their families and friends in the stricken area. Many call attempts in mobile cellular systems are blocked due to limited radio frequency resources. In this paper, as a solution to this problem, limiting the holding time of calls is investigated and a dynamic holding time limit (DHTL) method, which varies the holding time limit dynamically based on the number of call attempts is proposed. The effect of limiting holding time is investigated first using a computer simulation with a constant and heavy traffic load model. This simulation shows that the average holding time of calls is decreased as the holding time limit is reduced. But it also shows limiting the holding time decreases the number of calls blocked and forced call terminations at handover considerably. Next a simple estimation method for the holding time limit, which reduces the blocking rate to the normal rate for increasing call demand, is described. Finally, results are given of a simulation, which show that the DHTL method keeps good performance for a sudden and great traffic load fluctuation condition. Author
Computerized Simulation; Radio Frequencies; Time Dependence; Disasters; Telephones; Mobile Communication Systems
20060002168 Oki Electric Industry Ltd., Tokyo, Japan
Properties of an Orthogonal-Type Echo Canceller
Maeno, Takahiro; Kobayashi, Masaki; 1987 IEEE International Symposium on Circuits and Systems, Volume 2; 1987, pp. 442-445; In English; See also 20060002103; Copyright; Avail.: Other Sources
This paper describes the characteristics of an echo canceller that is based on a system of orthogonal functions. The features of the adaptive digital filter that employs a system of orthogonal functions (orthogonal-function ADF) will first be described. The poles can be positioned at any desired location inside the unit circle on the z-plane in the orthogonal-function ADF and the convergence speed does not decrease even when the poles are positioned. A computer simulation was conducted to compare the convergence speeds when a white signal and colored signal were used as the input signal. Simulation confirmed that the convergence speed of the orthogonal-function ADF decreases only slightly when a colored signal is used as the input signal, compared with the speed when a white signal is used. Author
Digital Filters; Adaptive Filters; Orthogonal Functions; Convergence; Computerized Simulation
20060002169 Oki Electric Industry Ltd., Tokyo, Japan
Improved Double Integration Delta-Sigma Modulations for A to D and D to A Conversion
Shoji, Yasuo; Suzuke, Takeo; 1987 IEEE International Symposium on Circuits and Systems, Volume 2; 1987, pp. 451-454; In English; See also 20060002103; Copyright; Avail.: Other Sources
This paper describes a new form of 'double integration' delta sigma modulator as the analog-to-digital and digital-to-analog converter for the voiceband signals. It has the following three features compared with the earlier double integration delta sigma modulator. 1) The processing of the sampling rate can be executed at 1/2 clock speed. 2) The low-voltage power drive and expansion of the dynamic range are possible because the internal integral voltage is 1/2 or less. 3) The noise component out of the baseband is attenuated more effectively to improve the signal-to-noise ratios. The properties of this new modulator and its performance are demonstrated with computer simulations. type is advantageous from the viewpoint of the circuit scale. Author
Digital to Analog Converters; Analog to Digital Converters; Delta Modulation; Signal to Noise Ratios; Voice Communication; Electric Potential; Dynamic Range
20060002245 Frequentis G.m.b.H., Vienna, Austria
VHF Channel Occupancy Measurements over Core Europe
Prinz, Johannes; Rihacek, Christoph; Sajatovic, Miodrag; Zazo, Santiago; Lopez-Perez, Javier; Perez-Alvarez, Ivan A.; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005, pp. 1-21; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The Broadband-VHF (B-VHF) project aims to develop a new integrated broadband VHF system for aeronautical voice and data link communications based on Multi-Carrier Code Division Multiple Access (MC-CDMA) technology. The B-VHF project is being conducted within the 6th Framework Programme of the European Commission (EC). The B-VHF system is intended to be deployed as an overlay system within the VHF aeronautical communications (COM) band (118- 137 MHz) by exploiting parts of the VHF spectrum that appear to be effectively unused by existing DSB-AM and other narrowband (NB) VHF systems. Alternative B-VHF deployment scenarios include other communications bands up to 1 GHz (e.g. DME band). These parts of the VHF spectrum, which can be re-used by the B-VHF system are location-dependent and are based on the overall current VHF channel occupancy observed during a defined time period. For the purposes of the B-VHF project, the VHF occupancy was defined as a fraction of channels (percentage of all 761 VHF narrowband channels) for which the received instantaneous power level has - at least instantaneously - exceeded the selected threshold value (dBm). Author (revised)
Very High Frequencies; Voice Communication; Systems Integration; Data Links; Broadband
20060002252 AeroSat Corp., USA
Transformational Cost Reduction for Airborne Internet
Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005, pp. 1-14; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Airborne internet objective are: To enable a safe, more secure, more cost efficient NAS. By eliminating communications as a constraint. On the economic viability of aviation related applications: very low cost; very high speed; scaleable; ubiquitous; secure; open; evolutionary. Derived from text
Cost Reduction; Internets; Viability
20060002261 Mitre Corp., USA
The Right Radar Backup for ADS-B
Crane, Leslie; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005, pp. 1-30; In English; See also 20060002231; Original contains color illustrations Contract(s)/Grant(s): DTFA01-01-C-00001; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
When ADS-B replaces radar in the National Airspace System as the principal surveillance tool for air traffic control, what will be the role of radar as a surveillance backup? What are the backup surveillance requirements? What are the tradeoffs between primary and secondary radar as a backup system? This presentation addresses these questions and presents alternative scenarios for radar surveillance backup for ADS-B. Author
Air Traffic Control; Secondary Radar; Surveillance
20060002264 Federal Aviation Administration, Washington, DC, USA
Communications Operating Concept and Requirements for the Future Radio System
Anderson, Gregg; Gonda, John; Chavez, Patricia; Hung, Brian; Saumsiegle, William; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005; 16 pp.; In English; See also 20060002231; Original contains color illustrations Contract(s)/Grant(s): DTFA01-01-C-00001; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The objectives are: Provide communications capacity for Air Traffic Management through 2030. Allow a realistic transition for service providers and airspace users. Support ATS and AOC communications for safety and regularity of flight. Address VHF spectrum depletion in both Regions. Investigate multi-mode avionics for implementation. Derived from text
Air Traffic Control; Communication Networks; Airspace; Safety
20060002272 Alenia Marconi Systems, Rome, Italy
Analysis of Air Traffic Control Systems Interference Impact on Galileo Aeronautical Receivers
DeAngelis, Massimiliano; Fantacci, Romano; Rinaldi, Claudio; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference andWorkshop; November 2005; 29 pp.; In English; See also 20060002231; Original contains color and black and white illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
A GNSS receiver (GPS, Galileo) operating in a civil aircraft is exposed to the signals transmitted from ATC (Air Traffic Control) Surveillance sensors, Aeronautical Navigation systems and other non-Aeronautical systems. The present study aims to investigate Galileo E5/L5 inband and out-of-band interference due to some ATC systems (Primary and Secondary radars, and VOR, DME, ILS, and TACAN Navaids), in terms of SNR and accuracy degradation. We performed the analysis through both a theoretical approach and a simulations activity. Through the theoretical approach, we analyzed the interference effects expressing the results in terms of SNR degradation as a function of the aircraft-ATC systems distance. We discovered that if the GNSS receiver is covered within 3dB beam width by the ATC system antenna, the interference is not negligible. For this reason, we analyzed the pulse blanking mitigation technique that is able to blank the interference with a negligible GNSS SNR degradation. In addition, exploiting the CNIT (National Interuniversity Telecommunications Consortium) Galileo Simulator, opportunely modified, we analyzed the effects of the Radar/Navaids interferences in terms of degradation of Galileo positioning accuracy, either with and without the mitigation process. The simulation activity has been performed considering a scenario closer to a real one, of an aircraft approaching Roma-Fiumicino airport. Both the theoretical analysis and the simulation activity highlighted that the DME systems effects on Galileo receivers could be disruptive without the application of the mitigation technique. The latter technique blanks all the interference effects with a simple algorithm and a limited increase in receiver complexity. Author
Galileo Spacecraft; Electromagnetic Interference; Navigation Instruments; Navigation Aids; Interoperability
20060002287 Mulkerin Associates, Inc., Springfield, VA, USA
Communications-Supported Concepts for Highjacked Aircraft
Mulkerin, Thomas; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005; 27 pp.; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Abstract There has been an increased emphasis on aviation security since the events of 9/11. The focus of this paper is on communications support for monitoring and reacting to activities on a commercial aircraft that has been highjacked. The concepts discussed are the use of a panic button, aircraft video and audio on demand, and automatic flight plan transmission. Implementation of these ideas does not require the development of new technologies, rather new applications for existing equipment. Thus, the concepts could be implemented soon. A panic button on a passenger aircraft could be used by an aircrew member to alert air traffic controllers and the Airline Operation Center (AOC) that a highjacking is occurring. An ACARS (Aircraft Communications Addressing and Reporting System) message along with a synthesized voice message containing identification and location data would be automatically transmitted when an aircrew member triggers the panic button. When there is a suspicion that a highjacking is in progress, an Air Traffic Control (ATC) controller could initiate video and audio surveillance 'on demand' via a secure communications link. In addition, the controller could initiate a process whereby the aircraft s Flight Management System (FMS) would transmit the current flight plan and automatically send changes. Author (revised)
Air Traffic Control; Communication Networks; Video Communication; Security; Passenger Aircraft
20060002294 Honeywell International, Inc., USA
Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop
November 2005; 21 pp.; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The private and business jet market poses a challenging environment for providing cost competitive communication links replicating terrestrial systems. This is particularly evident with today s airborne cellular market and these issues will increase when addressing the need to disseminate high quality strategic aeronautical weather and environmental information in the next generation of business jet wireless infrastructure.
While several techniques are being pursued, one tactic, driven by the high cost of hardware and maintenance for a satellite link, attempts to leverage the existing groundbased network. However, this highlights the difficult challenges to maintaining high quality of service for the ground and airborne user.
A potential key towards addressing these issues is the advent of a cost competitive reconfigurable antenna. As an optimized link to the terrestrial infrastructure, the antenna fulfills multiple roles and has a great impact on the overall system capabilities.
Honeywell is developing the ESCAN array, an 800 MHz 2.6 GHz reconfigurable aperture derived from a ground-based satellite tracking design originally investigated by the Georgia Tech Research Institute under the DARPA sponsored RECAP program. This array is composed of multiple metallic patches connected by high performance embedded RF switches. The switches are controlled by a matrix of low-power lasers illuminating photovoltaic devices. The connectivity is dynamically altered over a specified area to maximize a particular radiation performance metric such as directive gain or broad bandwidth. The aperture has the ability to dynamically place nulls, steer beams with a single feed, generate single highly directional or multiple beams, and control bandwidth. It will provide optimal communication capability in changing environmental conditions.
Aimed at applications demanding multi-functionality from a single aperture, ESCAN reduces the number of antennas required to support a platform and enables a rapid response in a changing communication infrastructure. Since ESCAN is designed specifically for cost sensitive airborne applications, Honeywell s proposed advances in the manufacture and electronic integration of these highly integrated apertures are a critical aspect of the program. From a larger perspective, this endeavor seeks to usher reconfigurable apertures into commercial markets by vastly improving manufacturability and cost compared to electronically scanned phased arrays. Author
Airborne Equipment; Communication Networks; Operating Costs; Radio Frequencies; Satellite Tracking; Phased Arrays
20060002307 Department of Defense, USA
Distributed Adaptive Operations: Command & Control of Networked-enabled Forces,Geographically Dispersed
Glaros, Gregory E.; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005, pp. 1-24; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Characteristics of the environment are: Fog and friction will always be present. Competition continuously increases complexity in order to survive and win. Solving for complexity requires: Getting a solution quickly rather than identifying a perfect solution over time then executing as fast as possible. Increased importance on collaboration and cooperation. Networking has greater value than individual performance. Reach dominates Richness. Increased need for higher transaction rates and high rates of learning. Diversity, variety, scale, and numbers matter. Iteration and continuous feedback is required. Derived from text
Adaptive Control; Command and Control; Network Analysis
20060002316 Analex Corp., Cleveland, OH, USA
Systems Methodology to Defining Surface Network Architecture
Nguyen, Thanh C.; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005; 23 pp.; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The current state of most modern airports surface network is fragmented, while the requirements for the integration of the Communications, Navigation, and Surveillance (CNS) in these airports are rapidly growing and urgently needed if the future vision of the National Airspace System (NAS) is to be realized. To address this problem, FAA and NASA under the Advanced Communications, Navigation, and Surveillance Architectures and Systems Technologies (ACAST) Project, have been exploring new concepts and technologies that will transform the NAS.
As an important component of this ACAST effort, NASA is researching communications requirements for surface network concept, analyzing current and future planned communications links against these growing surface Integrated CNS (ICNS) requirements and defining a surface ICNS network architecture that is scalable, reliable and flexible to meet current and future needs of airports operations. Traditionally, this task of analyzing and defining a network architecture as complex as the airport environment has been considered an art, depending on an individual s talents and knowledge of technologies, services and protocols. The results of this type of network architecture and design are often not reproducible.
In this paper, we will introduce a relatively new approach to network analysis, architecture and design and we will explore how this approach can be applied to defining the ACAST s Surface ICNS Network Architecture that may meet the current and future requirements of airport operations. This approach is viewing the surface network, along with its environment (everything that the surface network interacts with or impacts), as a system. Associated with this system are sets of services that are offered by the network to the rest of the system. Therefore, the surface network is considered as part of the larger system (such as the NAS), with interactions and dependencies between the surface network and its users, applications, and devices. This is a systems approach or methodology to networking. Author
Communication Networks; Network Analysis; Telecommunication
20060002317 Lockheed Martin Corp., Rockville, MD, USA
Integration of Airport Surface Communication Systems
Wang, Yang; Zhao, Yiyuan J.; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS) Conference and Workshop; November 2005; 24 pp.; In English; See also 20060002231; Original contains color illustrations; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Airport surface congestion has been recognized by FAA as a key traffic capacity problem in the National Airspace System (NAS). This article addresses the needs to integrate the current separate, dedicated, non-interoperable airport surface communication systems into a common communications platform. Designing a common communication infrastructure for all stakeholders requires the understanding of each stakeholder s needs for the surface operations. A methodology for collecting and expressing these needs has been discussed. Designing a common communication infrastructure also requires the proper integration of various communications and networking technologies. A reference model of an integrated airport surface communication systems has been proposed to meet the needs of all stakeholders. Author
National Airspace System; Telecommunication; Systems Integration
20060002361 Transport Canada, Downsview, Ontario, Canada
Strategies for Reducing Driver Distraction from In-Vehicle Telematics Devices: A Discussion Document
Apr. 2003; 34 pp.; In English Report No.(s): PB2006-102172; TP-1433-E; No Copyright; Avail.: National Technical Information Service (NTIS)
In-Vehicle Telematics refers to devices incorporating wireless communications technologies in order to provide information services, vehicle automation and other functions. Transport Canada is concerned that in-vehicle telematics devices are a threat to road safety because they increase driver distraction and cause an increase in distraction-related crashes. This concern is based on a substantial and mounting body of evidence indicating that using these devices impairs driving performance. NTIS
Information Systems; Telecommunication
Source: NASA.
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