Analysis of queuing behavior of automatic ESM systems

Radar electronic support measures (ESM) systems detect active emitters in a given area and determine their identities and bearings. The high arrival rate of radar pulses in dense emitter environments demands fast automatic processing of arriving pulses so that the ESM system can fulfill its functions properly in real time. Yet, the performance analysis of automatic ESM system in real life Is difficult since both pulse arrivals and widths can be specified only probabilistically. The success of queuing theory in many applications such as computer communication networks and flow-control has encouraged designers to utilize queuing theory in qualifying and judging the performance of automatic ESM systems in dense emitter environments. The queuing behavior of these systems is analytically evaluated under different service disciplines and elaborate computer simulations validate the results. The analysis involves statistical modeling of arrival and departure processes as well as distribution of service times. It permits estimating the blocking probability due to high arrival rates of intercepted radar pulses or due to limited speed of the deinterleaver processor. Queuing analysis is shown to be quite useful to quantitatively assess tradeoffs in ESM systems design     

Improving the productivity of complex electronic systems design byutilizing applied design methodologies

The design process of complex electronic systems consists of four traditional main stages, which are system design, electronic design, mechanical design, and design for manufacturing. Even today when many integrated computer aided design environments are in use for electronic systems design, we still seem to accept that the design process really has to follow this path of four individual design stages. It is common that we are dealing with data transfer problems between different types of CAE-applications. However, there is a possibility to avoid the disadvantages due to integration problems between the design stages if we decide to develop the design methodology itself instead of developing those independent software applications. One effective way to improve the productivity of complex electronic systems design is to tune the so-called systematic design approach by adding special aspects of electronic systems design into the questionnaires used for collecting the requirement lists for further mechanical design and DFM. Another important tool is the carefully made manufacturability analysis. The deep interaction of mechanical and electronic design, extended by manufacturability analysis can also lead to innovative solutions as presented previously by the author. In the article entitled “Manufacturability Analysis-A Useful Subset of Systems Engineering” we were able to show that the number of iteration cycles during the different design and manufacturing stages could be reduced by 50% compared to the conventional design methodology. In this paper, we illustrate additional tools to continue this promising development work     

航空发动机分布式控制系统结构分析

对近年来航空发动机分布式控制系统的研究作了简要分析。重点分析了航空发动机分布式控制系统的结构、功能和优点;比较了几种分布式数据总线和电源总线的优缺点,并指出了适用于航空发动机分布式控制系统的数据总线和电源总线选择;分析了发动机运行环境对开发分布式控制系统的影响,并提出了可能的解决方案;指出了开展航空发动机分布式控制系统研究的重要性和未来的发展方向。      

Reconfiguration of flight control systems for actuator failures

We consider the problem of designing fault tolerant control for transient failures in the flight control system caused by harsh electromagnetic environments. We examine principles of fault tolerant design and discuss integrated local supervisory control of these systems. As an example, we present a sample design of a control mixer to achieve fault tolerance in the event of failures in the actuators     

Optimal design of RTCs in digital circuit fault self-repair based on global signal optimization

Since digital circuits have been widely and thoroughly applied in various fields, electronic systems are increasingly more complicated and require greater reliability. Faults may occur in elec-tronic systems in complicated environments. If immediate field repairs are not made on the faults, elec-tronic systems will not run normally, and this will lead to serious losses. The traditional method for improving system reliability based on redundant fault-tolerant technique has been unable to meet the requirements. Therefore, on the basis of (evolvable hardware)-based and (reparation balance technology)-based electronic circuit fault self-repair strategy proposed in our preliminary work, the optimal design of rectification circuits (RTCs) in electronic circuit fault self-repair based on global sig-nal optimization is deeply researched in this paper. First of all, the basic theory of RTC optimal design based on global signal optimization is proposed. Secondly, relevant considerations and suitable ranges are analyzed. Then, the basic flow of RTC optimal design is researched. Eventually, a typical circuit is selected for simulation verification, and detailed simulated analysis is made on five circumstances that occur during RTC evolution. The simulation results prove that compared with the conventional design method based RTC, the global signal optimization design method based RTC is lower in hardware cost, faster in circuit evolution, higher in convergent precision, and higher in circuit evolution success rate. Therefore, the global signal optimization based RTC optimal design method applied in the elec-tronic circuit fault self-repair technology is proven to be feasible, effective, and advantageous.     

Optical communication systems for avionics

Avionic information processing and transmission requirements are increasing geometrically, with no end in sight, The only feasible way to meet them is to incorporate fiber-optic communication systems into avionic platforms, Such systems can be employed to replace standard electronic components, to augment existing systems, or to enable new technologies. In this paper, we survey the field of low-power communication systems from the avionics engineering perspective. We review the fundamental merits of optical fiber for information transmission and discuss various information modulation schemes. These modulation techniques determine the performance requirements for laser transmitters, We describe the horizontal- and vertical-cavity semiconductor lasers currently available for these systems, and measure their performance against the additional environmental constraints of avionics platforms. Finally, we outline expected near- and far-term trends in system and device development     

Transient performance and intelligent combination control of a novel spray cooling loop system

Effective thermal control systems are essential for the reliable working of insulated gate bipolar transistors （IGBTs） in many applications. A novel spray cooling loop system with integrated sintered porous copper wick （SCLS-SPC） is proposed to meet the requirements of higher device level heat fluxes and the harsh environments in some applications such as hybrid, fuel cell vehicles and aerospace. Fuzzy logic and proportional-integral-derivative （PID） policies are applied to adjust the electronic temperature within a safe working range. To evaluate the thermal control effect, a mathematical model of a 4-node thermal network and pump are established for predicting the dynamics of the SCLS-SPC. Moreover, the transient response of the 4 nodes and vapor mass flowrate under no control, PID and Fuzzy-PID are numerically investigated and discussed in detail.     

High speed plastic networks (HSPN): a new technology for today'sapplications

Decades ago, glass fiber promised to be the future of communications offering large bandwidth, low attenuation, and electromagnetic compatibility. For the long haul applications, this promise has been fulfilled. Today, glass fibers have yielded simple, reliable, and economic means of communicating worldwide. However, when it comes to shorter distances and rugged environments, glass fiber optics has not been the answer. Unforeseen rapid developments in software and display technology have enabled communications in the form of multimedia, E-mail, web pages, and video conferencing. These developments are pushing data rates higher and higher in application environments that are more severe, uncontrolled and require shorter connected intensive links. To achieve desired data rates and electromagnetic compatibility (EMC) using copper systems, shielded cable and connectors or parallel links are necessary, driving up cost and complexity. Glass fiber optic systems provide more than adequate bandwidth and superior EMC but cannot offer a cost effective, robust, user-friendly system. Recent developments have poised plastic optical fiber (POF) to fill the physical layer gap. This paper will discuss the recent developments in plastic fiber including appropriate application space, types of plastic optical fiber, ARPA-funded HSPN team, and recent POF developments     

Vehicular remote tolling services using EGNOS

Future Global Navigation Satellite Systems (GNSS) will significantly improve the performance of current navigation systems, providing new and enhanced capabilities. This will enable the implementation of innovative and advanced services and applications closer to the user's needs. In this framework, the road sector is one of the major potential markets for GNSS applications and, therefore, it is very promising for future EGNOS and GALILEO related applications. Satellite navigation receivers are now commonly installed in cars as a key tool for proving new services to people on the move such as electronic charging, real-time traffic information, emergency calls, route guidance, fleet management, or advance driving assistance systems. Specifically, a very important commercial opportunity is represented by the tolling-related applications. This paper describes the Vehicular Remote Tolling (VeRT) Project sponsored by Galileo Joint Undertaking (GJU) and performed in the frame of the first GJU Call under the EC VI Framework Programme. The overall design of the service provision architecture is also presented in this paper, together with the main topics related to the following activities focused on the service prototype demonstrator development.     

ECCM capabilities of an ultrawideband bandlimited random noise imaging radar

Investigated here is high-resolution imaging of targets in noisy or unfriendly radar environments through a simulation analysis of the ultrawideband (UWB) continuous-wave (CW) bandlimited random noise waveform. The linear FM chirp signal was selected as a benchmark radar waveform for comparison purposes. Simulation of the recovery of various types of target reflectivity functions (TRFs) for these waveforms were performed and analyzed. In addition, electronic counter-countermeasure (ECCM) capabilities for both types of systems were investigated. The results are compared using the error between the interference (jamming)-free recovered TRF and the recovered TRF under noisy conditions as a function of the signal-to-interference/jamming ratio (SIR/SJR). Our analysis shows that noise waveforms possess better jamming immunity (of the order of 5-10 dB improvement over the linear FM chirp) due to the unique radar correlation processing in the receiver.     

Airport information systems security

Airports are unique as no two airports are designed the same and, while each is a single facility, each is occupied by many different tenants who provide many different services. Each service may include one or more information systems, both automated and manual, running independently from all others. Because of high visibility events such as the bombing of Pan American Flight 103 in 1988, the explosion of TWA Flight 800 in 1996, and the most recent catastrophic events of September 11, 2001, increased security measures have been put in place to protect the flying public from terrorists. The need to share and exchange information effectively and in a timely manner between airport services and systems, with other airport facilities, outside organizations and government agencies, becomes greater each day. The increased requirements defined by previous policy, threat, vulnerability, and risk assessments can be used to derive security services for NAS Air Traffic Control (ATC) operations, as well as Airport Facility (AF) operations. However, conventional solutions may not be suited to the unique needs of an airport environment and may be operationally unacceptable in some cases. This discusses some of the ways that information systems security can help ensure that key security services, including access control and authentication, are available and implementable in all systems as needed in these unique airport environments.     

Analysis tools for the evaluation of maintenance software

Test packages written for built-in test (BIT) and mobile automatic test equipment (ATE) systems for the forward support of electronic and thermal imaging equipment used by the British Army are currently scrutinized and subjected to objective tests by test package evaluation and acceptance teams (TPEATs) before being accepted for field use. This is a time-consuming and costly exercise that can result in the rejection of unsuitable software. The result of such rejection on equipment logistics is for reaching, since the hardware will enter service without adequate maintenance support. In an attempt to address this problem a suite of programs aimed at assisting the verification and validation activities of the TPEAT at every stage of the software life cycle from requirements analysis through to testing and acceptance is being devised. The development of these tools is discussed     

Partially Ionized Plasmas in Astrophysics

Partially ionized plasmas are found across the Universe in many different astrophysical environments. They constitute an essential ingredient of the solar atmosphere, molecular clouds, planetary ionospheres and protoplanetary disks, among other environments, and display a richness of physical effects which are not present in fully ionized plasmas. This review provides an overview of the physics of partially ionized plasmas, including recent advances in different astrophysical areas in which partial ionization plays a fundamental role. We outline outstanding observational and theoretical questions and discuss possible directions for future progress.     

EM Transient Protection Requirements for Avionics LRUs

Avionics and electronic equipment installed in aircraft and air breathing missiles are required to operate without upset or damage when subjected to EM environments caused by lightning, NEMP, and Intrasystems transients. To simplify the design effort required to protect electronic equipment and minimize overlapping transient requirements and qualification tests, unified test requirements and procedures are needed. The goal of these unified test procedures would be to insure a known susceptibility level for each newly designed electronic Line Replaceable Unit (LRU). Ten avionics equipments in current Air Force inventory were tested for the purpose of developing unified procedure test methods. Operating LRUs were subjected to transients using common mode cable current (CMCC), groung potentials and chatteriing relay cable injection methods. Based on observed test results and review of current test requirements, test methods and test levels for unified test procedures for power-on transient tests of avionics equipment have been formulated.     

Environments in the Outer Solar System

The outer planets of our solar system Jupiter, Saturn, Uranus, and Neptune are fascinating objects on their own. Their intrinsic magnetic fields form magnetic environments (so called magnetospheres) in which charged and neutral particles and dust are produced, lost or being transported through the system. These magnetic environments of the gas giants can be envisaged as huge plasma laboratories in space in which electromagnetic waves, current systems, particle transport mechanisms, acceleration processes and other phenomena act and interact with the large number of moons in orbit around those massive planets. In general it is necessary to describe and study the global environments (magnetospheres) of the gas giants, its global configuration with its large-scale transport processes; and, in combination, to study the local environments of the moons as well, e.g. the interaction processes between the magnetospheric plasma and the exosphere/atmosphere/magnetosphere of the moon acting on time scales of seconds to days. These local exchange processes include also the gravity, shape, rotation, astrometric observations and orbital parameters of the icy moons in those huge systems. It is the purpose of this chapter of the book to describe the variety of the magnetic environments of the outer planets in a broad overview, globally and locally, and to show that those exchange processes can dramatically influence the surfaces and exospheres/atmospheres of the moons and they can also be used as a tool to study the overall physics of systems as a whole.     

Achieving higher levels of electronic integration throughsystem-on-chip

All aerospace vehicles have the common constraint of limited space for the electronic systems. The challenge has always been how to pack effective electronic systems into the space available. Higher levels of electronic integration can give a competitive advantage; for example, by providing extra channels in a communications satellite thereby increasing revenue to the operator. Today's deep sub-micron manufacturing processes for integrated electronics offer an opportunity for a step change for electronic functionality that can be packaged in a given space. This technology makes possible, for the first time, a true system-on-chip approach to electronic systems, which is already being exploited by the commercial sector in products such as the mobile telephone     

DF Vectoring: Application to Stationary Synchronous Satellites

Several methods of using an earth-based radio reference signal to determine the three-axis attitude of a synchronous satellite, and two types of spacecraft electronic systems (amplitude measurement and phase measurement), which obtain attitude and pointing information from the radio reference signal for orientating the spacecraft and for directing large-aperture antennas aboard the spacecraft are described. The earth-based radio reference signal also enables the electronic systems to determine angles to other ground stations with respect to fixed (reference) stations on the earth. These attitude- and angle-determining techniques are applicable to communications satellites, navigational satellites, and intersatellite data relay systems.     

Telecommunications Technology in Metropolitan Areas

The electronic communication technology available today offers the possibility of changing many patterns of information transfer in urban areas. There are three major trends which are converging to make this change possible. These are: 1) the technology to permit wideband information transfer manifested in the existing 2300/CATV/Cable System and in modification of the Bell network for wideband services; 2) the potential demand for a vast range of new services to persons operating in the urban areas; 3) the increasing demands for meeting mobile information transfer needs in the urban areas through radio systems operating in the 100 to 1000 MHz part of the spectrum. The extent to which these trends are allowed to converge will be a function of the quality of telecommunication policy formulation and execution. In order to formulate policy, it is necessary to have a vision of the future toward which to work. This paper will discuss the types of services possible with the technology presently available, which will have impact on future policy decisions.     

A survey of radar ECM and ECCM

Radar electronic countermeasure (ECM) and electronic counter-countermeasures (ECCM) form the principal conflicting pair in modern electronic warfare. The technical history and state of art of both the radar ECM and ECCM are surveyed and their development trends are predicted. The classification of ECCM techniques, compatibility of various ECCM devices in a radar system and effectiveness evaluation of radar ECM and ECCM systems are also discussed