• AN EXTENSION OF SOQPSK TO M-ARY SIGNALLING

      Bishop, Chris; Fahey, Mike; Phase IV Systems, Inc. (International Foundation for Telemetering, 2003-10)
      Shaped Offset Quadrature Phase Shift Keying (SOQPSK) has the advantages of low sidelobes and high detection probability; however, its main lobe has a fixed width set by the number of constellation points. By slightly modifying the modulation scheme, the four constellation points of quadrature shift keying can be changed to M constellation points where M is a power of 2. After this change, the power spectral density (PSD) retains low sidelobes, and the desirable property of being able to detect the signal by integrating over two symbol periods is retained.
    • TELEMETRY IN BUNDLES: DELAY-TOLERANT NETWORKING FOR DELAY-CHALLENGED APPLICATIONS

      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.
    • NETWORKED DATA ACQUISITION DEVICES AS APPLIED TO AUTOMOTIVE TESTING

      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.
    • AN ETHERNET BASED AIRBORNE DATA ACQUISITION 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.
    • A CELLULAR PHONE-CENTRIC MOBILE NETWORK ARCHITECTURE FOR WIRELESS SMALL SATELLITE TELEMETRY SYSTEM

      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.
    • 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.
    • REFERENCE ARCHITECTURE FOR SPACE DATA SYSTEMS

      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.
    • A Bit Error Rate Analysis of Offset QPSK over the Aeronautical Telemetry Multipath Channel

      Rice, Michael; Dang, Xiaoyu; Brigham Young University (International Foundation for Telemetering, 2003-10)
      The impact of multipath fading parameters on the probability of error for Offset QPSK (OQPSK) is derived. The multipath fading channel is modeled using the aeronautical telemetry channel model [1-2]. Expressions for the probability of bit error are derived that are a function of the multipath model parameters. The expressions are shown to agree with computer simulations and show that a strong multipath reflection with a short delay causes much more degradation than a weak multipath reflection with a long delay.
    • TELEMETRY DATA DISTRIBUTION UTILIZING A MULTICAST IP NETWORK

      DeLong, Brian; Sypris Data Systems (International Foundation for Telemetering, 2003-10)
      The efficient distribution of telemetry data via standard Ethernet networks has become an increasingly important part of telemetry system designs. While there are several methods and architectures to choose from, a solution based on IP multicast transmission provides for a fast and efficient method of distributing data from a single source to multiple clients. This data distribution method allows for increased scalability as data servers are no longer required to service individual client connections, and network bandwidth is minimized with multiple network clients being simultaneously serviced via a single data transmission.
    • HIGH RATE DATA BROADCAST SYSTEM FOR NPP IN-SITU APPLICATIONS

      Mirchandani, Chandru; Fisher, David; Brentzel, Kelvin; Coronado, Patrick; Harris, Carol; NASA (International Foundation for Telemetering, 2003-10)
      A vital part of all satellite development is the ground system that will be used to process the satellite downlink. To support the High-Rate Data (HRD) Downlink satellites planned for launch by the NPOESS Preparatory Project (NPP), GSFC has developed a Single Chassis System (SCS) solution, which provides data processing from RF to data product using leading-edge hardware components. The SCS is a hardware solution that meets and exceeds this rate requirement. In realtime, the SCS autonomously processes and delivers Direct Broadcast data from NPP satellites. An objective of the HRD System development was that it be an integrated processing element housed in a single commercial off-the-shelf PC capable of exceeding the near-term requirements of NPP and moving towards the mid and far term needs of NASA.
    • RANGE AND SPACE NETWORKING - WHAT’S MISSING

      Rash, James; Hogie, Keith; Criscuolo, Ed; Parise, Ron; NASA; Computer Sciences Corporation (International Foundation for Telemetering, 2003-10)
      A large selection of hardware and software components are readily available for supporting Internet communication in the ground network environment. These components can be used to construct very powerful and flexible communication systems. The Operating Missions as Nodes on the Internet (OMNI) project at NASA/GSFC has been defining and demonstrating ways to use standard Internet technologies for future space communication. Theses concepts and technologies are also applicable to test range telemetry applications. This paper identifies the network equipment and protocols to support end-to-end IP communication from range sensors and spacecraft instruments to end users. After identifying the end-to-end network hardware and software components, the paper discusses which ones are currently available and lists specific examples of each. This includes examples of space missions currently using Internet technology for end-to-end communication. It also lists missing pieces and includes information on their current status. The goal of this paper is also to stimulate thought and discussion on what steps need to be taken to start filling in the remaining missing pieces for end-to-end range and space network connectivity.
    • Wireless Transducer Systems Architectures – A User’s Perspective

      Blakely, Patrick A.; Boeing Company (International Foundation for Telemetering, 2003-10)
      This paper provides essential requirements and describes some possible architectures of so-called Wireless Transducers Systems from the user’s perspective and discusses the application advantages of each architecture, in the airplane-testing environment. The intent of this paper is to stimulate discussion in the transducer user and supplier communities and standards committees, leading to increased product suitability and lower cost for commercial off the shelf wireless transducer products.
    • A DESIGN FOR SATELLITE GROUND STATION RECEIVER AUTOCONFIGURATION

      De Leon, Phillip; Wang, Qingsong; Horan, Steve; Lyman, Ray; New Mexico State University (International Foundation for Telemetering, 2003-10)
      In this paper, we propose a receiver design for satellite ground station use which can demodulate a waveform without specific knowledge of the data rate, convolutional code rate, or line code used. Several assumptions, consistent with the Space Network operating environment, are made including only certain data rates, convolutional code rates and generator polynomials, and types of line encoders. Despite the assumptions, a wide class of digital signaling (covering most of what might be seen at a ground station receiver) is captured. The approach uses standard signal processing techniques to identify data rate and line encoder class and a look up table with coded sync words (a standard feature of telemetry data frame header) in order to identify the key parameters. As our research has shown, the leading bits of the received coded frame can be used to uniquely identify the parameters. With proper identification, a basic receiver autoconfiguration sequence (date rate, line decoder, convolutional decoder) may be constructed.
    • AN INTRODUCTION TO LOW-DENSITY PARITY-CHECK CODES

      Moon, Todd K.; Gunther, Jacob H.; Utah State University (International Foundation for Telemetering, 2003-10)
      Low-Density Parity-Check (LDPC) codes are powerful codes capable of nearly achieving the Shannon channel capacity. This paper presents a tutorial introduction to LDPC codes, with a detailed description of the decoding algorithm. The algorithm propagates information about bit and check probabilities through a tree obtained from the Tanner graph for the code. This paper may be useful as a supplement in a course on error-control coding or digital communication.
    • AIR-GROUND TELEMETRY SYSTEMS FOR RESEARCH HELICOPTERS

      Kasper, Eugene F.; Leong, Gary; Ames Research Center (International Foundation for Telemetering, 2003-10)
      This paper describes the development of a compact mobile telemetry system using commercial-off-the-shelf components. The personal computer-based systems support microwave pulse code modulation and serial spread-spectrum radio modem telemetry. The mobile ground station provides data display and archiving of test activities, air-ground communications between experimenters and the flight test crew, and acts as a flight test Differential Global Positioning System base station. The success of the systems indicates that functional telemetry capabilities can be established for small flight test programs at modest cost.
    • TCP EXTENSIONS FOR A SATELLITE CHANNEL

      Hu, Xuenan; Zhou, Tingxian; Harbin Institute of Technology (International Foundation for Telemetering, 2003-10)
      The usage of Internet is explosively growing. Satellite has become a choice solution breaking through the bandwidth bottleneck and the terrain limit. TCP, which is well suited to terrestrial networks, performs poorly on a satellite channel. The reduced efficiency and QoS(Quality of Service) mainly result from three characteristics of a satellite link: higher bit error rate, the high latency, asymmetry. For this issue, the paper presents connection-subsection network architecture, and brings forward S-TCP based on the architecture.
    • Drowning in Data, Starving for Knowledge OMEGA Data Environment

      Coble, Keith; Veridian Incorporated (International Foundation for Telemetering, 2003-10)
      The quantity T&E data has grown in step with the increase in computing power and digital storage. T&E data management and exploitation technologies have not kept pace with this exponential growth. New approaches to the challenges posed by this data explosion must provide for continued growth while providing seamless integration with the existing body of work. Object Oriented Data Management provides the framework to handle the continued rapid growth in computer speed and the amount of data gathered and legacy integration. The OMEGA Data Environment is one of the first commercially available examples of this emerging class of OODM applications.
    • SMART ANTENNA (DIVERSITY) AND NON-FEEDBACK IF EQUALIZATION TECHNIQUES FOR LEO SATELLITE COMMUNICATIONS IN A COMPLEX INTERFERENCE ENVIRONMENT

      Haghdad, Mehdi; Feher, Kamilo; University of California Davis; American SkySat; FQPSK Consortium – Digcom, Inc. (International Foundation for Telemetering, 2003-10)
      An improved performance smart diversity was invented to improve the signal performance in a combined selective fading, Additive White Gaussian Noise (AWGN), Co-channel interference (CCI) and Doppler shift environment such as the LEO satellite channel. This system is also applicable to aeronautical and telemetry channels. Smart diversity is defined here as a mechanism that selects at each moment the best branch in a n-branch diversity system based on the error quality with no default branch and no prioritization. The predominant novelty of this discovery is the introduction of multi level analog based Pseudo Error Detectors (PSED) in every branch. One of the advantages of PSED is that it is a non redundant error detection system, with no requirement for overhead and no need for additional valuable spectrum. This research was motivated by problems in LEO satellite systems due to low orbit and high relative speed with respect to the ground stations. The system is independent of the modulation techniques and is applicable to both coherent and non-coherent detections. The results from simulations using dynamic simulation techniques and hardware measurements over dynamic channels show significant improvement of both the Bit Error Rate (BER) and the Block Error Rate (BLER).
    • RESEARCH OF SECURITY HARDWARE IN PKI SYSTEM

      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.
    • THE CASE FOR MIS-MATCHED FILTERING IN NONLINEARLY AMPLIFIED FQPSK AND GSM INTER-OPERABLE SYSTEMS

      Gonzalez, Maria C.; University of California, Davis (International Foundation for Telemetering, 2003-10)
      Structures for power-efficient systems, requiring the use of non-linear amplifiers and thus Mis-Matched filtering, are presented. These architectures allow for changeable amounts of power, bit rate, and modem selectable formats. The benefits include power/spectral efficiency, in addition to robust operation in mobile environments . Alternatives to matched filter receivers are addressed for power constrained systems associated with mobile systems in frequency selective channel environments. Two types of modulation format FQPSK[1][2][3] and GMSK[4], with different mismatch filters at the receiver, are analyzed.