• TELEMETRY AND SERVICE CONVERGENCE IN MIXED PROTOCOL TEST RANGE NETWORKS

      Kovach, Bob; Terawave Communications (International Foundation for Telemetering, 2004-10)
      In the past few years, an evolution has been occurring in test range network topologies. With the proliferation of IP-based networks at the desktop, range officers are seeking ways to extend IP-based networks to the test range, to derive the cost and operational benefits offered with IP technology. This transition is not without its own set of problems. The operational transition from the traditional, ATM-based ranges to IP-based ranges must be addressed. In many cases, it is desired to maintain the ATM range, and add IP capabilities as time and budget permits. The net result is that frequently a mixed protocol network emerges. Terawave Communications has been developing telemetry transport solutions for both ATM and IP-based networks, along with technology to enable convergence of additional services such as video, voice, and data across test ranges. Terawave has developed a solution for various network topologies from ATM-only and IP-only to mixed protocol implementations, which supports end-to-end interworking of telemetry, video, and additional services over mixed protocol networks. In this paper, Terawave will detail the implementation decisions made in the course of application development, and share a framework for enabling seamless intra- and inter- range communication of telemetry and mixed services.
    • Telemetry Best Source Selection at White Sands Missile Range

      Engler, Richard (Ray); Kirby, Johanna; White Sands Missile Range (International Foundation for Telemetering, 2004-10)
      Over the last year, the Telemetry Data Center at White Sands Missile Range has conducted extensive comparative testing between its’ 20 year old Best Source Selector and several “off the shelf” selectors currently available. This paper explores the concerns involved in the process of selecting a new Best Source Selector and examines the inherent problems and differences associated with the old and new selectors.
    • TELEMETRY LINK RELIABILITY IMPROVEMENT VIA “NO-HIT” DIVERSITY BRANCH SELECTION

      Jefferis, Robert P.; TYBRIN Corporation (International Foundation for Telemetering, 2004-10)
      Multipath propagation consisting largely of specular reflection components is known to be the major channel impairment in many aeronautical mobile telemetry (AMT) applications. Adaptive equalizers are not effective against flat fading commonly created by strong power delay profile components representing small fractions of the transmitted symbol period. Avoidance and diversity techniques are the only practical means of combating this problem. A new post-detection, no-hit diversity branch selector is described in this paper. Laboratory and limited flight test data comparing non-diversity, selection diversity and intermediate frequency (IF) combining techniques are presented.
    • TESTING OF A DTN PROTOCOL - CCSDS FILE DELIVERY PROTOCOL INTER-IMPLEMENTATION TESTING FINAL REPORT

      Carper, Richard D.; Ciccone, Massimiliano; Rockwell, Kathy Bryan; Space Data Systems; European Space Agency; California Institute of Technology (International Foundation for Telemetering, 2004-10)
      The CCSDS has developed the “CCSDS File Delivery Protocol” (CFDP), as a disruption/delay tolerant file transfer protocol. CFDP allows an automatic, reliable file transfer between spacecraft and ground (in both directions) designed to support the operation of spacecraft by means of file transfer and remote file system management. To support the development and fielding of the protocol in an international and cross-supporting environment, an international, inter-operability test program has been developed and successfully executed. First phase testing involved five independent implementations of the Core Procedures of the protocol. The second phase tests involve multi-hop transferring of files using the Extended Procedures. The third phase involves the testing of the SFO Procedures. The latter two phases involved two independent protocol implementations, namely, those of ESA and JPL. This paper constitutes a final report on the process of testing, the test results, the experience gained, and the resulting plans to extend this methodology to other areas within the CCSDS.
    • THROUGHPUT AND LATENCY PERFORMANCE OF IEEE 802.11E WITH 802.11A, 802.11B, AND 802.11G PHYSICAL LAYERS

      Shah, Vishal; Cooklev, Todor; IEEE (International Foundation for Telemetering, 2004-10)
      IEEE 802.11e is an amendment of the medium-access control (MAC) layer of the standard for wireless local area networking IEEE 802.11. The goal of 802.11e is to provide 802.11 networks with Quality of Service (QoS). 802.11 has three physical layers (PHY) of practical importance: 802.11b, 802.11a, and 802.11g. 802.11a and 802.11g provide data rates between 6 and 54 Mbps, and 802.11b provides data rates of 5.5 Mbps and 11 Mbps. However these data rates are not the actual throughput. The actual throughput that a user will experience will be lower. The throughput depends on both the PHY and MAC layers. It is important to estimate what exactly is the throughput when the physical layer is 802.11a, 802.11b, or 802.11g, and the MAC layer is 802.11e. In other words, how does providing QoS change the throughput for each of the three physical layers? In this paper we provide answers to this problem. Analytic formulae are derived. The maximum achievable throughput and minimum delay involved in data transfers are determined. The obtained results have further significance for the design of high-throughput wireless protocols.
    • TIME SYNCHRONIZATION AND FREQUENCY PRECISION CONTROL AMONG MULTIPLE BASE STATIONS IN GPS

      Haifang, Wang; Qishan, Zhang; Beijing University (International Foundation for Telemetering, 2004-10)
      In this paper, we develop a method for achieving high precision of time and frequency synchronization among multiple base stations in GPS system. We first describe the basic theory of timing and frequency checking, and then analyze several error sources which influence the precision of time and frequency synchronization. Furthermore, we derive explicit formula for calculating the precision of time and frequency. Tested results have indicated that our method can indeed achieve very high time and frequency precision.
    • THE TIMELINESS OF ASYNCHRONOUS PACKET MULTIPLEXING IN SWITCHED ETHERNET

      Qiao, Li; XiaoLin, Zhang; Huagang, Xiong; Yuxia, Fei; Beijing University of Aeronautics & Astronautics (International Foundation for Telemetering, 2004-10)
      Powered by single-segment switched interconnection, Ethernet can be used in time-critical data acquisition applications. Unlike synchronous time division multiple access, asynchronous packet streams result in congestions and uncertain multiplexing delays. With the delay analysis in the worst case and probabilistic guaranteeing conditions, we restrict the packet-sizes, intervals or traffic burstiness a priori to regulate delay deviations within acceptable scales. Some methods of combinatorics and stochastic theory, e.g. Cumulant Generating Function and the Large Deviation Principle, are used and verified by some simulation-based computations. The influence of time varying delay for telemetry applications is also discussed in some sense.
    • Total Border Security Surveillance

      Herold, Fredrick W.; Fredrick Herold & Associates, Inc. (International Foundation for Telemetering, 2004-10)
      This paper describes a system of Total Border Surveillance, which is cost effective, closes existing gaps and is less manpower intensive than the current techniques. The system utilizes a fleet of commercially available aircraft converted to unmanned capability, existing GPS and surveillance systems and autonomous ground stations to provide the desired coverage.
    • USING LABVIEW TO DESIGN A FAULT-TOLERANT LINK ESTABLISHMENT PROTOCOL

      Horan, Stephen; Deivasigamani, Giriprassad; New Mexico State University (International Foundation for Telemetering, 2004-10)
      The design of a protocol for a satellite cluster link establishment and management that accounts for link corruption, node failures, and node re-establishment is presented in this paper. This protocol will need to manage the traffic flow between nodes in the satellite cluster, adjust routing tables due to node motion, allow for sub-networks in the cluster, and similar activities. This protocol development is in its initial stages and we will describe how we use the LabVIEW Sate Diagram tool kit to generate the code to design a state machine representing the protocol for the establishment of inter-satellite communications links.
    • Using Telemetry Front-end Equipment and Network Attached Storage Connected to Form a Real-time Data Recording and Playback System

      Gatton, Tim; General Dynamics Advanced Information Systems (International Foundation for Telemetering, 2004-10)
      The use of traditional telemetry decommutation equipment can be easily expanded to create a real-time pulse code modulation (PCM) telemetry data recorder. However, there are two areas that create unique demands where architectural investment is required: the PCM output stage and the storage stage. This paper details the efforts to define the requirements and limits of a traditional telemetry system when used as a real-time, multistream PCM data recorder with time tagging.
    • Using the CCSDS File Delivery Protocol (CFDP) on the Global Precipitation Measurement mission

      Ray, Tim; NASA (International Foundation for Telemetering, 2004-10)
      The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) to provide reliable delivery of files across space links. Space links are typically intermittent, requiring flexibility on the part of CFDP. Some aspects of that flexibility will be highlighted in this paper, which discusses the planned use of CFDP on the Global Precipitation Measurement (GPM) mission. The operational scenario for GPM involves reliable downlink of science data files at a high datarate (approximately 4 megabits per second) over a space link that is not only intermittent, but also one-way most of the time. This paper will describe how that scenario is easily handled by CFDP, despite the fact that reliable delivery requires a feedback loop.
    • The Wallops Flight Facility Rapid Response Range Operations Initiative

      Kremer, Steven; Bishop, Jim; NASA; LJT and Associates, Inc. (International Foundation for Telemetering, 2004-10)
      While the dominant focus on short response missions has appropriately centered on the launch vehicle and spacecraft, often overlooked or afterthought phases of these missions have been the launch site operations and the activities of launch range organizations. Throughout the history of organized spaceflight, launch ranges have been the bane of flight programs as the source of expense, schedule delays, and seemingly endless requirements. Launch Ranges provide three basic functions: (1) appropriate geographical location to meet orbital or other mission trajectory requirements, (2) project services such as processing facilities, launch complexes, tracking and data services, and expendable products, and (3) safety assurance and property protection to participating personnel and third-parties. The challenge with which launch site authorities continuously struggle is the inherent conflict arising from flight projects whose singular concern is execution of their mission, and the range’s need to support numerous simultaneous customers. So, while tasks carried out by a launch range committed to a single mission pale in comparison to efforts of a launch vehicle or spacecraft provider and could normally be carried out in a matter of weeks, major launch sites have dozens of active projects with dozens of separate sponsoring organizations. Accommodating the numerous tasks associated with each mission, when hardware failures, weather, maintenance requirements, and other factors constantly conspire against the range resource schedulers, make the launch range just as significant an impediment to responsive missions as launch vehicles and their cargo. The obvious solution to the launch site challenge was implemented years ago when the Department of Defense simply established dedicated infrastructure and personnel to dedicated missions, namely an Inter Continental Ballistic Missile. This however proves to be prohibitively expensive for all but the most urgent of applications. So the challenge becomes how can a launch site provide acceptably responsive mission services to a particular customer without dedicating extensive resources and while continuing to be cost effective and to serve other projects? NASA’s Wallops Flight Facility (WFF) is pursuing solutions to meet exactly this challenge. NASA, in partnership with the Virginia Commercial Space Flight Authority, has initiated the Rapid Response Range Operations (R3Ops) Initiative. R3Ops is a multi-phased effort to incrementally establish and demonstrate increasingly responsive launch operations, with an ultimate goal of providing ELV-class services in a maximum of 7-10 days from initial notification. This target will be pursued within the reality of simultaneous concurrent programs, and ideally, largely independent of specialized flight system configurations. WFF has recently completed Phase 1 of R3Ops that included an in-depth collection (through extensive expert interviews) and limited software modeling of individual launch operations processes by various range disciplines. This modeling is now being used to identify existing inefficiencies in current procedures within each process and to show interdependencies. Existing practices are being tracked to provide a baseline as new procedures are implemented and evaluated. Technology infusion efforts have been identified and are currently underway in the area of space-based range safety and communications. Phase II of this effort will involve evaluation and implementation of real time software process flow tools, software integration of processes already defined into an integrated model, and spiral software development of the process flow tools. The technology efforts will begin maturing with flight demonstrations and integration into the operational environment. The completion of Phase II will enable R3Ops efficiencies to meet the requirements of many upcoming commercial and government programs. A critical duty in this phase will be the identification of an effective software tool that meets launch range requirements in a responsive multi-user environment.
    • XML: A GLOBAL STANDARD FOR THE FLIGHT TEST COMMUNITY

      Corry, Diarmuid; Cooke, Alan; ACRA CONTROL (International Foundation for Telemetering, 2004-10)
      Much effort has been spent on developing physical layer standards to ease multi-vendor inter-operability. However as anyone familiar with real-life system integration knows a large gap exists in defining system configuration and set-up, not just between vendors but also between different groups on the base. Different solutions to this problem have been attempted (for example TMATS). However, the emergence of XML (eXtensible Markup Language) as a commercial standard presents a new opportunity to define a powerful and extensible tool for data-interchange between different systems. This paper introduces the self-documenting standard for information exchange that is XML. A generic model for flight test data acquisition is presented. Finally, an XML vocabulary (or schema) based on this model is proposed. This schema could form the basis for an industry wide XML standard to simplify the problem of data interchange between vendors, between programs, even between different databases in the same organisation.