Zetocha, Paul; Kirtland Air Force Base (International Foundation for Telemetering, 2003-10)
      There is an increasing desire in many organizations, including NASA and the DoD, to use constellations or fleets of autonomous spacecraft working together to accomplish complex mission objectives. At the Air Force Research Laboratory’s (AFRL) Space Vehicles Directorate we are investigating and developing architectures for commanding and controlling a cluster of cooperating satellites. For many space missions, large monolithic satellites are required to meet mission requirements. In many cases this results in costly satellites which are more complex, more susceptible to failure, and which have performance characteristics that are less than optimal due to realistic physical size limitations. Recently various organizations have begun to explore how distributed clusters of cooperating satellites can replace their larger monolithic counterparts resulting in an overall cost reduction, enhanced mission performance, and increased system fault tolerance. Large clusters of satellites flying in formation are required to have some level of on-board autonomy in order to: fly within specified tolerance levels; perform collision avoidance; address fault detection, isolation, and resolution (FDIR); share knowledge; and plan and schedule activities. In addition, from an operations standpoint, commanding and controlling a large cluster of satellites can be very burdensome for ground operators. At AFRL we are addressing these issues by development of an on-board Cluster Management system which will, in essence, provide the capability to treat a cluster of satellites as a single virtual satellite. A systems level approach is being taken, therefore from a ground perspective the ground control station must also be able to treat the cluster as a virtual satellite. [1] This paper will describe our Cluster Management system, which is the intelligent entity that is responsible for making cluster level decisions and which enables the satellite cluster to function as a virtual satellite. The cluster manager functionality can be broken down into the following five areas: • Command and control • Cluster data management • Formation flying • Fault management • On-board Planning This paper will contain a detailed description of the Cluster Manager architecture along with its various modules.

      Meihong, Li; Qishan, Zhang; Jun, Wang; Beihang University; Beijing University Of Post And Telecommunication (International Foundation for Telemetering, 2003-10)
      SSL protocol is one industrial standard to protect data transferred securely on Internet. Firstly SSL is analyzed, according to its characteristics, one solution plan on mobile bank based on SSL is proposed and presented, in which GPRS technology is adopted and elliptic curve algorithm is used for the session key, finally several functional modules of mobile bank are designed in details and its security is analyzed.
    • Data Aided ML Symbol Timing Estimation for MIMO Systems Using a Polyphase Filterbank

      Liu, Kejing; Rice, Michael; Brigham Young University (International Foundation for Telemetering, 2003-10)
      This paper derives the maximum likelihood (ML) symbol timing estimator for a frequency non-selective multiple-input, multiple output (MIMO) channel assuming linear modulation and known data and known channel gains. The non-frequency selective fading assumption means the multipath delay spread is small so that the symbol time delay is the same across all receive antennas. Both a closed-loop and an approximate open-loop architecture are demonstrated. The open-loop or “batch” estimator is based on a polyphase filterbank implementation of the derivative matched filter.
    • Space-Time Coding for Avionic Telemetry Channels

      Wang, Jibing; Yao, Kung; Whiteman, Don; University of California, Los Angeles; National Aeronautical Space Administration (International Foundation for Telemetering, 2003-10)
      Multiple antennas promise high data capacity for wireless communications. Most space-time coding schemes in literature focus on the rich scatter environment. In this paper, we argue that minimax criterion is a good design criterion for space-time codes over the avionic telemetry channels. This design criterion is different than those of space-time codes over rich scattering Rayleigh fading channels. Theoretical and numerical results show that the codes with optimal performance in Rayleigh fading channels do not necessarily have optimal performance in avionic telemetry channels. Therefore, the space-time codes should be carefully designed/selected when used in the avionic telemetry channels.

      Shames, Peter; Yamada, Takahiro; California Institute of Technology; Institute of Space and Astronautical Science (International Foundation for Telemetering, 2003-10)
      This paper introduces the Reference Architecture for Space Data Systems (RASDS) that is being developed by CCSDS. RASDS uses five Views to describe architectures of space data systems. These Views are derived from the viewpoints of the Reference Model of Open Distributed Processing (RM-ODP), but they are slightly modified from the RM-ODP viewpoints so that they can better represent the concerns of space data systems.

      Gudmundson, Stephan; NetAcquire Corporation (International Foundation for Telemetering, 2003-10)
      While the transition to IP internetworking in space-based applications has a tremendous upside, there are significant challenges of communications efficiency and compatibility to overcome. This paper describes a very high efficiency, low-risk, incremental architecture for migrating to IP internetworking based on the use of proxies. In addition to impressive gains in communications bandwidth, the architecture provides encapsulation of potentially volatile decisions such as particular vendors and network technologies. The specific benchmarking architecture is a NetAcquire Corporation COTS telemetry system that includes built-in TCP-Tranquility (also known as SCPS-TP) and Reed-Solomon Forward Error Correction capabilities as well as a specialized proxy-capable network stack. Depending on network conditions, we will show that the effective bandwidth for satellite transmissions can be increased as much as a factor of one hundred with no external changes to existing internetworking equipment.
    • IEEE P1451.4 Smart Transducers Template Description Language

      Jones, Charles H.; Edwards Air Force Base (International Foundation for Telemetering, 2003-10)
      The IEEE 1451.4 smart transducer interface standard [1] provides a mechanism for both analog and digital, or mixed mode, interfacing to sensors and actuators, which are collectively referred to as transducers. The analog mode allows normal interfacing to the transducer. The digital mode is intended to provide the ‘smarts’ by allowing the transducer to provide basic information to the application system. This information is referred to as the transducer electronic data sheet (TEDS) and contains information ranging from serial number to calibration data and electrical characteristics. A major driving force behind the development of the standard was to minimize the amount of memory required to store a TEDS; with a stated objective of only needing 256 bits, although more are allowed. This requires a method of mapping the bits in a precise fashion. This bit mapping is accomplished through templates which are text based files written in the Template Description Language (TDL). The TDL is a formal language similar to programming languages, but with considerably less looping and conditional control. This is because the entire purpose of the language is to map bits and not to implement general processing or mathematical capabilities. This paper outlines the functionality and syntax of the TDL.

      Brierley, Scott; The Boeing Company (International Foundation for Telemetering, 2003-10)
      Calculating the power spectral density (PSD) at the transducer or data acquisition system offers advantages in a network-based telemetry system. The PSD is provided in real time to the users. The conversion to PSD can either be lossless (allowing a complete reconstruction of the transducer signal) or lossy (providing data compression). Post-processing can convert the PSD back to time histories if desired. A complete reconstruction of the signal is possible, including knowledge of the signal level between the sample periods. Properly implemented, this method of data collection provides a sharp anti-aliasing filter with minimal added cost. Currently no standards exist for generating PSDs on the vehicle. New standards could help telemetry system designers understand the benefits and limitations calculating the power spectral density in a network-based telemetry system.

      Dai, Jiwang; DeSelms, Thomas; Grozalis, Edward; L3 Communications; Veridian Engineering (International Foundation for Telemetering, 2003-10)
      There is growing interest in the airborne instrumentation community to adopt commercial standards to obtain scalable data rates, standards based interoperability, and utilization of Commercial Off The Shelf (COTS) products to reduce system costs. However, there has been few such data acquisition systems developed to date. L-3 Telemetry East has developed a prototype called the Network Data Acquisition System (NetDAS), which is based on the 10/100 Base-T Ethernet standard, TCP/UDP/IP network protocols and an industrial Ethernet switch. NetDAS has added network capability to the legacy MPC-800 telemetry system by replacing the existing formatter module with a formatter/controller based on a COTS CPU module and a custom designed bridge module. NetDAS has demonstrated transmission bit rates as high as 20 Mbps from a single unit using UDP/IP and an Ethernet switch. The NetDAS system has also demonstrated scalable and distributed architecture.

      Li, Mingmei; Guo, Qing; Harbin Institute of Technology (International Foundation for Telemetering, 2003-10)
      This paper aims to add the information access capabilities to enable user’s mobile terminals in a wireless small satellite telemetry system. The cellular phone-centric mobile network architecture provides wireless communication link; telemetry information is provided to users in a highly personalized form according to the end-user’s range. We choose a reference system-level model of network architecture and compare its performance with common small satellite telemetry network link; evaluation results derived using a known analytical model. The result of original hypotheses, network architecture’s prototype includes both analytical performance evaluation and simulation techniques, are discussed in detail.

      Wenhua, Qi; Qishan, Zhang; Hailong, Liu; BeiHang University (International Foundation for Telemetering, 2003-10)
      Security hardware based on asymmetric algorithm is the key component of Public Key Infrastructure (PKI), which decides the safety and performance of system. Security device in server or client have some common functions. We designed the client token and cryptographic server to improve the performance of PKI, and got obvious effect.

      Wolejsza, Chester J. Jr.; The Aerospace Corporation (International Foundation for Telemetering, 2003-10)
      The United States Government, through the Integrated Program Office (IPO), currently operates a converged polar orbiting constellation of POES and DMSP satellites to acquire, process and disseminate meteorological and environmental data on a global scale. Because of the increasing need for more precise and timely meteorological data, the IPO is developing the follow on system known as the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The NPOESS system is expected to use a modernized, CCSDS compatible data acquisition and distribution network, and will provide more timely data than for the current POES/DMSP satellites. The NPOESS satellite system will also continue the collection of long-term environmental data as a follow on to NASA’s Earth Observation System (EOS). The continuation of NASA’s EOS system will begin with a risk reduction effort in support of NPOESS, known as the NPOESS Preparatory Project (NPP). This paper will describe the CCSDS implementation that both the NPP and NPOESS satellites are expected to use beginning with the launch of the NPP spacecraft in 2006. The launch of the first NPOESS satellite is anticipated in 2009.

      Davis, Jesse; Kyker, Ron; Berry, Nina; Sandia National Laboratories (International Foundation for Telemetering, 2003-10)
      A particular engineering aspect of distributed sensor networks that has not received adequate attention is the system level hardware architecture of the individual nodes of the network. A novel hardware architecture based on an idea of task specific modular computing is proposed to provide for both the high flexibility and low power consumption required for distributed sensing solutions. The power consumption of the architecture is mathematically analyzed against a traditional approach, and guidelines are developed for application scenarios that would benefit from using this new design.

      Lucas, Jason; Alix, Kevin; Lessmann, Kurt; FI 2010 (International Foundation for Telemetering, 2003-10)
      Sponsored by the Central Test and Evaluation Investment Program (CTEIP) under the Director of Test and Evaluation (DOT&E), the Foundation Initiative 2010 (FI 2010) project is chartered to enable interoperability among ranges, facilities, and simulations in a timely and cost-efficient manner and to foster reuse of range assets and future software systems. To achieve this vision, FI 2010 has developed and is validating a common architecture called the Test and Training Enabling Architecture (TENA), which provides for real-time software system interoperability using the TENA Middleware, as well as interfaces to existing range assets, C4ISR systems, and simulations. The TENA middleware is being developed using an iterative development process, with functionality being released in four “spirals.” The current software version, Release 3.0, was built upon previous releases and provides some key functionality enhancements to include multicast transport, vector data types and User Datagram Protocol (UDP) multicast communication support. This paper will provide detailed information on the current status of the FI 2010 project, the TENA Middleware Release 3.0, and how the TENA software has been utilized to support test and training events (e.g., Millennium Challenge 02).

      Whiteman, Don; Sakahara, Robert; NASA (International Foundation for Telemetering, 2003-10)
      The use of remote ground stations for telemetry data-relay in space launch applications is costly and limits the geographic locations for launches of future Reusable Launch Vehicle (RLV) systems. The National Aeronautics and Space Administration Space-based Telemetry and Range-Safety (STARS) Study is investigating the use of satellite data relay systems as a replacement or supplement for ground-based tracking and relay stations. Phase-1 of STARS includes flight testing that evaluates satellite data-relay feasibility, defines satellite system performance limitations, and generates requirements for the development of future satellite telemetry data relay systems. STARS Phase-1 ground-test results and goals for the Phase-2 system development and flight-testing are also presented.

      Sorenson, Carl E.; Yarbrough, Stanton K.; Freudinger, Lawrence C.; Gonia, Philip T.; ManTech International Corporation; NASA (International Foundation for Telemetering, 2003-10)
      This paper overviews the Research Environment for Vehicle-Embedded Analysis on Linux (REVEAL), which is an open standards framework for the creation and deployment of realtime embedded and network distributed data systems. REVEAL is an ongoing project at NASA Dryden to evaluate the feasibility and benefits of using Linux in a modern generic web-enabled data system for measurement and telemetry network research, by actually building such a system. Novel features are described, such as XML based self-configuring, self-verifying and self-documenting software, and automatic XML metadata generation. The REVEAL architecture is described, including the core server and scheduler, and the management of system and user job processing. Performance, timing, determinism, and security issues are discussed, as well as the advantages and limitations of Linux.

      Burleigh, Scott; California Institute of Technology (International Foundation for Telemetering, 2003-10)
      Delay-tolerant networking (DTN) is a system for constructing automated data networks in which end-to-end communication is reliable despite low data rates, possible sustained interruptions in connectivity, and potentially high signal propagation latency. As such it promises to provide an inexpensive and robust medium for returning telemetry from research vehicles in environments that provide meager support for communications: deep space, the surface of Mars, the poles or the sub- Arctic steppes of Earth, and others. This paper presents an overview of DTN concepts, including “bundles” and the Bundling overlay protocol. One possible scenario for the application of DTN to a telemetry return problem is described, and there is a brief discussion of the current state of DTN technology development.

      Mastrippolito, Luigi; Aberdeen Proving Ground (International Foundation for Telemetering, 2003-10)
      The US Army Aberdeen Test Center (ATC) is acquiring, transferring, and databasing data during all phases of automotive testing using networked data acquisition devices. The devices are small ruggedized computer-based systems programmed with specific data acquisition tasks and then networked together with other devices in order to share information within a test item or vehicle. One of the devices is also networked to a ground-station for monitor, control and data transfer of any of the devices on the net. Application of these devices has varied from single vehicle tests in a single geographical location up to a 100-vehicle nationwide test. Each device has a primary task such as acquiring data from vehicular data busses (MIL-STD-1553, SAE J1708 bus, SAE J1939 bus, RS-422 serial bus, etc.), GPS (time and position), analog sensors and video with audio. Each device has programmable options, maintained in a configuration file, that define the specific recording methods, real-time algorithms to be performed, data rates, and triggering parameters. The programmability of the system and bi-directional communications allow the configuration file to be modified remotely after the system is fielded. The primary data storage media of each device is onboard solid-state flash disk; therefore, a continuous communication link is not critical to data gathering. Data are gathered, quality checked and loaded into a database for analysis. The configuration file, as an integral part of the database, ensures configuration identity and management. A web based graphical user interface provides preprogrammed query options for viewing, summarizing, graphing, and consolidating data. The database can also be queried for more detailed analyses. The architecture for this network approach to field data acquisition was under the Aberdeen Test Center program Versatile Information System Integrated On-Line (VISION). This paper will describe how the merging of data acquisition systems to network communications and information management tools provides a powerful resource for system engineers, analysts, evaluators and acquisition personnel.

      Orozco, Gina; Klipsch School of Electrical and Computer Engineering (International Foundation for Telemetering, 2003-10)
      The NMSUSat is part of the AFRL/NASA University Nanosatellite program. The constellation will consist of a main microsatellite that will have a command link from ground and a telemetry link to ground while a picosatellite will act as a sensor reporting data to the microsatellite. Innovative command and data handling will be incorporated at low cost and greater accessibility. In this paper we present the necessary communications and control architecture for the space segment and the ground segment of the nanosatellite.

      Sunshine, Carl; Williams, Lance; The Aerospace Corporation; Northrop Grumman (International Foundation for Telemetering, 2003-10)
      A critical area for achieving interoperability between satellite control networks is the means chosen to interconnect Satellite Operations Centers and remote antenna systems. The CCSDS Space Link Extension (SLE) services are good candidates for this purpose, but national security space activities have demanding requirements for accuracy of data transfer, controlled delay, and security, which may not be fully achievable with the existing recommendations. The US Air Force developed a test bed to evaluate the SLE protocols during live satellite contacts, for both data transfer and management functions such as scheduling, configuring ground resources, and status reporting. Performance was generally satisfactory, but several extensions were found to be necessary. The SLE services provide a promising basis for use in ground stations to support both legacy Air Force interfaces and newer standards based satellite control services.