By Topic

Systems Journal, IEEE

Issue 1 • Date March 2008

Filter Results

Displaying Results 1 - 25 of 29
  • [Front cover]

    Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (155 KB)  
    Freely Available from IEEE
  • IEEE Systems Journal publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (35 KB)  
    Freely Available from IEEE
  • Table of contents

    Page(s): 1 - 2
    Save to Project icon | Request Permissions | PDF file iconPDF (36 KB)  
    Freely Available from IEEE
  • Guest Editorial Recent Advances in Global Navigation and Communication Satellite Systems

    Page(s): 3 - 6
    Save to Project icon | Request Permissions | PDF file iconPDF (422 KB)  
    Freely Available from IEEE
  • Simulation of Multi-Element Antenna Systems for Navigation Applications

    Page(s): 7 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1779 KB) |  | HTML iconHTML  

    The application of user terminals with multiple antenna inputs for use with the global navigation satellite systems like Global Positioning System (GPS) and Galileo has attracted more and more attention in the past years. Multiple antennas may be spread over the user platform and provide signals required for the platform attitude estimation or may be arranged in an antenna array to be used together with array processing algorithms for improving signal reception, e.g., for multi-path and interference mitigation. In order to generate signals for testing of receivers with multiple antenna inputs and corresponding receiver algorithms in a laboratory environment, a unique hardware signal simulation tool for wavefront simulation has been developed. The signals for a number of antenna elements are first generated in a flexible user defined geometry as digital signals in baseband and then mixed up to individual RF-outputs. This paper describes the principle functionality of the system and addresses some calibration issues. Measurement setups and results of data processing with simulated signals for different applications are shown and discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance Evaluation of a Precorrelation Interference Detection Algorithm for the GNSS Based on Nonparametrical Spectral Estimation

    Page(s): 20 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB) |  | HTML iconHTML  

    This paper deals with a signal processing precorrelation method to detect the presence of interference at a global navigation satellite system (GNSS) receiver site. In particular, a nonparametric spectral estimation approach based on the Welch windowed periodogram will be considered here. The performance of the proposed detector, in terms of detection probability, for a given false-alarm probability value, will be derived by means of an analytical approach and resorting to computer simulations. A performance comparison with previously proposed precorrelation methods will also be presented in order to highlight the better behavior of the proposed approach that makes it suitable for safety of life (SoL) applications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time-Frequency Excision for GNSS Applications

    Page(s): 27 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1706 KB) |  | HTML iconHTML  

    Interference detection and mitigation in global navigation satellite systems (GNSSs) are important issues for both military and civilian applications. In this paper, a novel time-frequency algorithm for GNSS application is proposed. The use of infinite impulse-response notch filters for the interference excision is introduced and analytical formulas for the detection of the disturbing signals are derived. The proposed method is tested by simulations and compared with time-frequency excision algorithms reported in literature, proving its effectiveness for interference removal. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Two-Pole and Multi-Pole Notch Filters: A Computationally Effective Solution for GNSS Interference Detection and Mitigation

    Page(s): 38 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1632 KB) |  | HTML iconHTML  

    In a global navigation satellite system (GNSS) receiver, the presence of detection and mitigation units, capable of reducing the impact of disturbing signals, can extremely enhance the position accuracy. However, the presence of such units is usually limited to professional receivers that dispose of additional computational power that can be used for interference detection and mitigation. In this paper, the two-pole notch filter, that is the natural extension of the one-pole notch filter, is proposed as computationally effective solution for interference detection and mitigation. The notch filter structure and the adaptive algorithm employed for tracking the disturbing signal are analyzed, and an interference detection unit, based on the adaptive algorithm convergence, is proposed. The two-pole notch filter coupled with the detection unit is used as elementary block for the design of a multi-pole notch filter that can efficiently mitigate more than one CW interference. Theoretical and simulative analyses show the feasibility and the good performance of the proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Integrated NAV-COM Systems: Assisted Code Acquisition and Interference Mitigation

    Page(s): 48 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1082 KB) |  | HTML iconHTML  

    In this paper, the problem of code acquisition for global navigation satellite systems (GNSS) is investigated in the presence of interference. A low-complexity interference mitigation technique is proposed to combat the effect of interference, which offers the potential for improved performance especially when high power jammers affect the reception. For practical implementation, an integrated navigation-communication network architecture is proposed, composed by an assistance network to aid code synchronization and an interference management system, augmenting the GNSS local component to enhance the system quality of service. Accordingly, an overall assistance network is proposed to estimate the interference characteristics and broadcast them to conventional terminals along with a rough time and frequency reference to improve code acquisition performance. Analytical and simulated results are provided, in the presence of binary offset carrier (BOC) modulation, showing the clear potential of assistance GNSS to significantly improve performance and reduce terminal complexity at the same time. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cross-Layer Design of Dynamic Bandwidth Allocation in DVB-RCS

    Page(s): 62 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1503 KB) |  | HTML iconHTML  

    In this paper, a novel cross-layer framework for optimizing the dynamic bandwidth allocation (DBA) of a digital video broadcast (DVB)-return channel satellite (RCS) system using adaptive coding is proposed. The design of the medium access control (MAC) methods taking into account the adaptive physical layer and higher layers' quality of service (QoS) requirements is cast as an optimization problem by using the network utility maximization (NUM) framework applied within the satellite subnetwork. Hierarchical and global solving procedures fully compliant with the DVB-RCS standard are proposed. They do not only provide minimum bandwidth guarantees but also maximize fairness. Further, they allow a joint optimization of the time slot size and overall system efficiency while minimizing signalling overhead. A reduced computational complexity algorithm to solve the DBA problem is presented. In practical terms, it increases the number of connections with absolute and relative QoS requirements the system can manage and facilitates the interoperability of the satellite network within an Internet protocol (IP) environment. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bandwidth-Effective Design of a Satellite-Based Hybrid Wireless Sensor Network for Mobile Target Detection and Tracking

    Page(s): 74 - 82
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2169 KB) |  | HTML iconHTML  

    Wireless sensor networks (WSNs) have the potential to assist advanced target tracking applications. The major challenge related to the design of such networks is to cope with the energy and computational limitations that characterize sensor nodes. To address this problem, we propose a hybrid architecture that integrates two sensor categories. The first performs basic detection and tracking functions while the second supports complex tasks such as imaging and broadband communication via a satellite network. Moreover, we develop a technique that allows vision sensors adapting the rate of the exchanged data according to the target activity in the monitored zone. Finally, a tracking approach taking into consideration the error on local sensor position measurements is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The TCP “Adaptive-Selection” Concept

    Page(s): 83 - 89
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (657 KB) |  | HTML iconHTML  

    The rapidly increasing importance of wireless communications (including satellite), together with the rapid growth of high speed networks, pose new challenges to transmission control protocol (TCP). Among them, the most prominent are long round trip times (RTTs), not negligible packet error rates (PER), and very large bandwidths. To overcome them, a wide variety of TCP enhancements has been presented in the literature with different purposes and capabilities. However, as most proposals aim to address different impairments, they result optimized for specific network environments. Therefore, given the increasing level of heterogeneity of present and future networks, the choice of ldquothe bestrdquo TCP enhancement seems a quite irresolvable problem, depending on the characteristics of the specific connections. The TCP adaptive-selection concept, presented and discussed in this paper, aims to circumvent this problem by providing an alternative approach that challenges at the root the idea that only one TCP enhancement must be adopted, not only on the whole network in general, but also on the same server machine. In fact, by extending the concept that underlies adaptive coding and modulation (ACM) to transport layer, TCP adaptive-selection envisages the concurrent adoption of different TCP versions on the same server, the better to match the different impairments present on different connections. The implication of this novel approach, as well as the possible criteria to be adopted for the TCP selection, are deeply discussed in this paper, where a particular emphasis is given to the ldquodynamicrdquo TCP adaptive-selection variant. Preliminary results, referring to a simple network topology, chosen to enlighten the mechanism of the TCP adaptive-selection technique, are also provided. They are quite encouraging and justify the following remarks on feasibility and the discussion of some implementation proposals. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Experimental Missions in W-Band: A Small LEO Satellite Approach

    Page(s): 90 - 103
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2338 KB) |  | HTML iconHTML  

    W-band (75-110 GHz) is proposed nowadays as a valuable alternative to intensively-exploited Ku- and Ka-bands for high-speed transmission over satellite networks. In such a framework, some experiments are being carried out, which are targeted to verify the feasibility of exploitation of W-band for broadband service deployment. From a theoretical viewpoint, the large bandwidth availability and the scarce amount of interference typical of W-band should guarantee high capacities. Nevertheless, many crucial aspects are still to be carefully investigated, e.g., signal propagation issues, RF impairments, choice of modulation and coding, efficient antenna design, etc. In this paper, an overview is made on the low Earth orbit (LEO) nano-satellite mission in-orbit key-test and validation of W-band (IKNOW). IKNOW mission is an ongoing advanced feasibility study part of an Italian Space Agency Project, named W-band analysis and verification (WAVE), coordinated by the Department of Electronic Engineering, University of Rome ldquoTor Vergatardquo. The main objective of the IKNOW mission is to tackle some of the unexplored critical aspects concerning W-band satellite transmission. In such a perspective, IKNOW should be regarded as a ldquopilot mission,rdquo whose results will be used for a first uplink-downlink satellite channel characterization, in-orbit validation of W-band technology, and space qualification processes. This paper is focused on the research work carried out in a preliminary phase of the IKNOW study and will also consider a number of elements related to the mission configuration, payload architecture, link analysis, potential RF impairment factors, and atmospheric effects. Proposed analysis and preliminary results shown can provide to interested readers the basic guidelines that will drive the practical implementation of IKNOW mission, as well as the most relevant issues to be faced by future developers of W-band missions using small LEO satellites. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High Performance Communication and Navigation Systems for Interplanetary Networks

    Page(s): 104 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (866 KB) |  | HTML iconHTML  

    The increasing development of technologies enabling efficient space exploration and data communications has recently fostered a number of scientific missions, aimed at supporting the research in the field of geology and astronomy. To this end, the design of an effective telecommunication infrastructure is the challenge offered to research scientists and space engineers. In particular, the definition of a network architecture suitable to support both communication and navigation services is of paramount importance for future space missions. In this view, this paper reviews protocols and architectures presently used in space missions and proposes improved transmission strategies, relying upon a packet-layer coding approach, which is expected to improve the overall performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Disturbance Observer-Based Robust Control of Free-Floating Space Manipulators

    Page(s): 114 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB) |  | HTML iconHTML  

    A disturbance observer-based control scheme is proposed for free-floating space manipulator with nonlinear dynamics derived using the virtual manipulator approach. The derived dynamic equation uses only link angles as generalized coordinates, which is suitable for the controller design in joint space. Since joint coupling, model uncertainties in robot dynamics are treated as lumped disturbances, a disturbance observer is developed at each joint of degree-of-freedom space manipulator to decouple and simplify the controller design. Simulation results of a six-link space manipulator show that the proposed scheme achieves superior performance, especially when large external disturbances are present. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Technical Feasibility and Relative Productivity of Alternate NASA Robotic Missions to a Lunar Dark Crater

    Page(s): 120 - 128
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1394 KB) |  | HTML iconHTML  

    Two concepts for large-scale, complex, robotic missions to search for frozen water at the lunar south pole are systematically analyzed to determine their relative productivity and investment requirements. A concurrent design team, a technology-assessment tool, and a sensitivity model are integrated to search a large, complex trade space. Performance goals for a broad portfolio of missions comprising NASA's lunar exploration program are optimized subject to budget, workforce, and other nontechnical constraints. Explicit distinction is made between enabling and enhancing technologies. Uncertainties and dependencies are included within the optimization framework. Given the constraints used in this analysis, the study determines that the longer mission [using a radioisotope thermoelectric generator (RTG)] would return 14 times the value of the shorter mission (using a methanol-oxygen fuel cell) for roughly a 17% increase in cost, and would be enabled with the recommended temporal technology portfolio. To assess the robustness of the investment recommendations, other potential fuel-cell chemistries are evaluated along with potential improvements in rover speed and autonomy, and a reduced activity profile. Results indicate that a lithium-oxygen fuel cell would enable the highest level of productivity among the three fuel cells studied, though not as high as that permitted by an RTG. For the shorter duration mission concepts, it was found that productivity could be enhanced by reducing the number of activities from the baseline 15 to 4, thereby permitting time for each activity to be more fully accomplished. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Visualization Framework for Real Time Decision Making in a Multi-Input Multi-Output System

    Page(s): 129 - 145
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2791 KB) |  | HTML iconHTML  

    Human beings have the capacity to make quick and accurate decisions when multiple objectives are involved provided they have access to all the relevant information. Accurate visual measures/decision surfaces (maps) are critical to the effectiveness of this process. This paper introduces a methodology that allows one to create a visual decision making interface for any multi-input multi-output (MIMO) system. In this case, the MIMO is thought of in the broadest sense to include battlefield operations, complex system design, and human support systems (rehabilitation). Our methodology starts with a Bayesian causal network approach to modeling the MIMO system. Various decision making scenarios in a typical MIMO system are presented. This is then followed by a description of the framework that allows for the presentation of the relevant scenario dependent data to the human decision maker (HDM). This presentation is in the form of 3-D surface plots called decision surfaces. Additional decision making tools (norms) are then presented. These norms allow for single value numbers to be presented along with the decision surfaces to better aid the HDM. We then present some applications of the framework to representative MIMO systems. This methodology easily adapts to systems that grow bigger and also when two or more systems are combined to form a larger system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Services: A System's Perspective

    Page(s): 146 - 157
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB) |  | HTML iconHTML  

    A system's perspective of services is contained herein. Analogous to manufacturing, services can and should also be viewed from a system's perspective. While the interdependences, similarities, and complementarities of manufacturing and services are significant, there are considerable differences between goods and services, including the shift in focus from mass production to mass customization (whereby a service is produced and delivered in response to a customer's stated or imputed needs). In general, a service system can be considered to be a combination or recombination of three essential components-people (characterized by behaviors, attitudes, values, etc.), processes (characterized by collaboration, customization, etc.), and products (characterized by software, hardware, infrastructures, etc.). Furthermore, inasmuch as a service system is an integrated system, it is, in essence, a system-of-systems (SoS) which objectives are to enhance its efficiency (leading to greater interdependency), effectiveness (leading to greater usefulness), and adaptiveness (leading to greater responsiveness). The integrative methods include a component's design, interface, and interdependency; a decision's strategic, tactical, and operational orientation; and an organization's data, modeling, and cybernetic consideration. A number of insights are also provided, including an alternative SoS view of services; the increasing complexity of systems (especially service systems), with all the attendant life-cycle design, human interface, and system integration issues; the increasing need for real-time, adaptive decision making within such an SoS; and the fact that modern systems are also becoming increasingly more human-centered, if not human-focused-thus, products and services are becoming more complex and more personalized or customized. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Aloha from the big island of Hawaii (WAC 2008)

    Page(s): 158 - 159
    Save to Project icon | Request Permissions | PDF file iconPDF (770 KB)  
    Freely Available from IEEE
  • 2nd Annual IEEE Systems Conference

    Page(s): 160
    Save to Project icon | Request Permissions | PDF file iconPDF (494 KB)  
    Freely Available from IEEE
  • 2008 Workshop International Consortium on System of Systems (ICSOS)

    Page(s): 161
    Save to Project icon | Request Permissions | PDF file iconPDF (489 KB)  
    Freely Available from IEEE
  • 2008 IEEE International Conference on System of Systems Engineering (SoSE) and 1st ICSoS Workshop

    Page(s): 162
    Save to Project icon | Request Permissions | PDF file iconPDF (642 KB)  
    Freely Available from IEEE
  • Special issue on resilience engineering

    Page(s): 163
    Save to Project icon | Request Permissions | PDF file iconPDF (840 KB)  
    Freely Available from IEEE
  • Special issue on creating a global earth observation system of systems

    Page(s): 164
    Save to Project icon | Request Permissions | PDF file iconPDF (499 KB)  
    Freely Available from IEEE
  • Special issue on grid resource management

    Page(s): 165
    Save to Project icon | Request Permissions | PDF file iconPDF (592 KB)  
    Freely Available from IEEE

Aims & Scope

The IEEE Systems Journal is created to provide a systems-level focused forum for application-oriented manuscripts that address complex systems and system-of-systems of national and global significance

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Professor Vincenzo Piuri
Università degli Studi di Milano