In this thesis, we present a MAC-layer packet scheduling algorithm, called Best-effort Packet Scheduling Algorithm(BPA), for real-time switched Ethernet networks. BPA considers a message model where application messages have trans-node timeliness requirements that are specified using Jensen's benefit functions. The algorithm seeks to maximize aggregate message benefit by allowing message packets to inherit benefit functions of their parent messages and scheduling packets to maximize aggregate packet-level benefit. Since the packet scheduling problem is NP-hard, BPA heuristically computes schedules with a worst-case cost of O(n^2), faster than the O(n^3) cost of the best known Chen and Muhlethaler's Algorithm(CMA) for the same problem. Our simulation studies show that BPA performs the same or significantly better than CMA. We also construct a real-time switched Ethernet by prototyping an Ethernet switch using a Personal Computer(PC) and implementing BPA in the network protocol stack of the Linux kernel for packet scheduling. Our actual performance measurements of BPA using the network implementation reveal the effectiveness of the algorithm. Finally, we derive timeliness feasibility conditions of real-time switched Ethernet systems that use the BPA algorithm. The feasibility conditions allow real-time distributed systems to be constructed using BPA, with guaranteed soft timeliness. / Master of Science

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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The Modular Range Interface (ModRI) is a reliable networked data acquisition system used to acquire and disseminate dissimilar data. ModRI’s purpose is to connect TSPI systems to a central computer network. The modular hardware design consists of an SBC, COTS network interfaces, and other COTS interfaces in a VME form factor. The modular software design uses C++ and OO patterns running under an RTOS. Current capabilities of ModRI include acquisition of Ethernet, PCM data, RS-422/232 serial data, and IRIG-B time. Future strategies might include stand-alone data acquisition, acquisition of digital video, and migration to other architectures and operating systems.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper describes the TENA architecture, which has been proposed by the Foundation Initiative 2010 (FI 2010) project as the basis for future US Test Range software systems. The benefits of this new architecture are explained by comparing the future TENA-enabled range infrastructure with the current situation of largely non-interoperable range resources. Legacy equipment and newly acquired off-the-shelf equipment that does not directly support TENA can be integrated into a TENA environment using TENA Gateways. This paper focuses on issues related to the construction of such gateways, including the important issue of real-time requirements when dealing with real-world data acquisition instruments. The benefits of leveraging commercial off-the-shelf (COTS) Data Acquisition Systems that are based on true real-time operating systems are discussed in the context of TENA Gateway construction.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Western Aeronautical Test Range (WATR) Integrated Next Generation System (WINGS) Mission Segment provides data acquisition, processing, display and storage in support of each project’s mission at NASA Dryden Flight Research Center (DFRC). The network architecture for WINGS Mission Segment is responsible for distributing a variety of information from the Telemetry and Radar Acquisition and Processing System (TRAPS), which is responsible for data acquisition and processing, to the Mission Control Centers (MCCs) for display of data to the user. WINGS consists of three TRAPS and four MCCs, where any TRAPS can drive any one or multiple MCCs. This paper will address the requirements for the TRAPS/MCC network and the design solution.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Complete real time testing of a telemetry tracking system typically requires the use of a cooperative target operating under conditions specially set up to simulate actual flight scenarios. This is a very expensive, time-consuming process and does not necessarily exercise all of the functions and capabilities available in new digital antenna controllers. This paper introduces Radar Environment Simulator technology and its application to testing of telemetry tracking systems. Measured results are shown, demonstrating that operational environment simulation is a valuable approach to quickly and effectively characterize the real time operation of a telemetry tracking system.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes a real-time implementation of the pattern recognition technology originally developed by BBN [Delatizky et al] for post-processing of time-sampled telemetry data. This makes it possible to monitor a data stream for a characteristic shape, such as an arrhythmic heartbeat or a step-response whose overshoot is unacceptably large. Once programmed to recognize patterns of interest, it generates a symbolic description of a time-series signal in intuitive, object-oriented terms. The basic technique is to decompose the signal into a hierarchy of simpler components using rules of grammar, analogous to the process of decomposing a sentence into phrases and words. This paper describes the basic technique used for pattern recognition of time-series signals and the problems that must be solved to apply the techniques in real time. We present experimental results for an unoptimized prototype demonstrating that 4000 samples per second can be handled easily on conventional hardware.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Telemetry systems designed to support the current needs of mission-critical applications often have stringent real-time requirements. These systems must guarantee a maximum worst-case processing and response time when incoming data is received. These real-time tolerances continue to tighten as data rates increase. At the same time, end user requirements for COTS pricing efficiencies have forced many telemetry systems to now run on desktop operating systems like Windows or Unix. While these desktop operating systems offer advanced user interface capabilities, they cannot meet the realtime requirements of the many mission-critical telemetry applications. Furthermore, attempts to enhance desktop operating systems to support real-time constraints have met with only limited success. This paper presents a telemetry system architecture that offers real-time guarantees while at the same time extensively leveraging inexpensive COTS hardware and software components. This is accomplished by partitioning the telemetry system onto two processors. The first processor is a NetAcquire subsystem running a real-time operating system (RTOS). The second processor runs a desktop operating system running the user interface. The two processors are connected together with a high-speed Ethernet IP internetwork. This architecture affords an improvement of two orders of magnitude over the real-time performance of a standalone desktop operating system.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Unmanned Aerial Vehicles (UAV) are becoming a significant asset to the military. This has given rise to the development of the Vehicle Control and Simulation System (VCSS), a low-cost ground support and control system deployable to any UAV testing site, with the capability to support ground crew and pilot training, real-time telemetry simulation, distribution, transmission and reception, mission planning, and Global Positioning System (GPS) reception. This paper describes the development of the VCSS detailing its capabilities, demonstrating its use in the field, and showing its novel use of internet technology for vehicle control telemetry distribution.

International Telemetering Conference Proceedings / October 26-29, 1987 / Town and Country Hotel, San Diego, California / The Telemetry Systems Operation (TSO) of CSC in Lompoc, California, has been developing telemetry systems since October 1981. Three major turnkey systems have been developed as well as several smaller derivative systems. Each system, built for a different end-user, was custom fit to support unique requirements and often represented several different techniques for accommodating similar problems within different system architectures. This paper describes the evolution of TM system architectures developed by TSO Lompoc, and the special engineering problems solved in the course of their development to provide the user with accommodating telemetry systems that are responsive, expandable, and cost-effective.