• Hypermedia and Expert Systems Applied to Space Vehicle Monitoring & Control

      Bost, J. D.; Le, T. C.; Mangan, P. K.; Meloan, M. D.; Sutton, S. A.; Turner, S. R. (International Foundation for Telemetering, 1989-11)
      The Defense Meteorological Satellite Program (DMSP) weather satellite supports worldwide defense operations by the acquisition of global visual and infrared cloud data and other specialized meteorological, oceanographic, and solar data. In support of DMSP, prototypes are currently under development that will demonstrate the viability of expert systems, real-time graphics, and hypermedia-based information navigation for space vehicle monitoring & control.
    • Data Rate Reduction Using a Digital Anti-Aliasing Filter

      Lee, Kyong H.; Maschhoff, Robert H.; Gulton Data Systems (International Foundation for Telemetering, 1989-11)
      In this paper we explore the limits of data rate or sample rate reduction that can be accomplished by sharp cutoff band limiting filters in a PCM data acquisition system. The results with practical analog filtering techniques are compared with those possible with digital filtering techniques. A typical 2:1 reduction in telemetry bit rate is shown to be practical using digital vs analog techniques. The resultant sample rates as low as 2.5 times the filter cutoff frequency has implications in the reconstruction algorithms which are also discussed. It is shown that by using practical and appropriate interpolation techniques or sample rate multiplication processes the data fidelity can be preserved. Thus the data user is assured that no information is being lost.
    • International Participation in AOS Standards Development

      Lenhard, Klaus G.; European Space Agency (International Foundation for Telemetering, 1989-11)
      During the current decade, international cooperation in space projects has become more and more popular and this trend is increasing. Initially, this involved only single missions with agencies flying payloads on other agencies' spacecraft. Later, this trend continued with international ventures, involving different agencies. In the immediate future, even more challenging scenarios are foreseen. The best known example and prime driver for such sophisticated missions will be the Space Station Freedom and its participating partners' spacecraft. Some of the international missions (ESA missions) are described briefly in this paper, in order to set the scene for a better understanding of the complex needs for standards within advanced orbiting systems. These ventures call for efficient means for cooperation and interoperability. Part of these requirements can be met by following international standards for space communications and space data systems. The Consultative Committee for Space Data Systems (CCSDS) undertook the task of integrating the space data systems requirements and developing appropriate recommendations for data systems standards for these Advanced Orbiting Systems (AOS). All international partners in the Space Station Freedom Program participated in the definition, development, and review of the AOS recommendations. The need for better cooperation in space communications via data relay satellite prompted the formation of a three party international panel called the Space Network Interoperability Panel (SNIP). An important aspect is the need for verification and validation of the concept and of the detailed technical recommendations. For the immediate future, special compatibility campaigns, involving the international agencies are planned in order to ensure the smooth application and functioning of the AOS recommendations.
    • Space Station-Era Ground Data Handling

      Smith, Gene A.; Goddard Space Flight Center / NASA (International Foundation for Telemetering, 1989-11)
      To support the Space Station-era space data flows through ground facilities, plans to handle peak return link data rates ranging from 300 Mbps to 1200 Mbps and average rates growing from 50 Mbps to hundreds of Mbps are being made. These numbers represent orders of magnitude greater rates than are handled today. Simply relaying the data to destinations, however, is not sufficient (nor so straightforward). Because of multiplexing of data, on-board tape recording and playback, noise, and other problems with the space-to-ground link, these data must be reassembled for users into the sequences in which the data were originally produced on-board with error checking, retransmission, correction, or flagging as required to eliminate or tag erroneous data. In the past these services (called Level Zero Processing) have required large operations staffs and have involved delays of 30 to 90 days for final formatting and shipping of data tapes to users. NASA's expectations for improving the SS-era operations depend on providing time ordered, error corrected or flagged data sets with no redundant data packets within 24 hours of receipt on the ground with backup of data for one week. These data sets would be transmitted electronically to data centers for higher level processing and would require no more operations personnel than are required today for systems processing less than 1/100 of the data. To support a variety of user requirements, some of the data will be provided in real time or, if recorded on-board, as priority playback data. Other data sets will be created from on-board system engineering or housekeeping data combined with attitude, position, and time parameters into ancillary data packets. On the ground enhancement of the on-board ancillary data packets will provide standard calibrations and transformations not available on-board. Remote access to an interactive ancillary database will allow users to select and withdraw specified parameters based on user-defined criteria. The collection of these services is referred to as ground data handling and will be a critical component of the Space Station-era ground data operations and mission management system under development at Goddard Space Flight Center for NASA institutional support of Space Station-compatible missions. Challenges represented by this need for more ground processing capability include: * High speed, high rate multipath processors capable of continuous, real-time operation. * High volume data storage systems with high rate data ingest, rapid access to separate segments of data sets, and high rate data output. * Sophisticated information and system management services to provide system configuration monitoring and control, user support, and minimal human interaction. * Interactive database structures with traceable parameter updating and self-identified, standard data set formatting.
    • Using AI To Simulate Spacecraft and Automate operations

      Golden, Marilyn; Ortiz, Dennis; Ford Aerospace (International Foundation for Telemetering, 1989-11)
      Software simulation is playing an increasing role in the entire product development life cycle. However, traditional software simulation tools do not fit easily into the intergrated environment required. Recent AI techniques can alleviate the problems involved with intergrating simulation tools through out the development cycle so they can then become the basis for automated operations after the systems have been deployed. Ford Aerospace has developed a software tool that interacts with the user to model the problem domain. The tool automatically provides a continuous, time-sliced simulation fo the modeled domain's behavior. Model-building is object oriented and requires no programming. The system uses a series of integrated graphic screens, controlled by mouse selection, and therefore requires only a few hours of training. Once developed, the domain model can serve as the knowledge base for trade studies made during the development process for V+V of the system during the testing phases and for automated analysis and fault diagnosis and correction during operations. Most complex functions required to be performed on the gorund to control spacecraft can be automated. The paper will discuss how PARAGON can be used (1) to help the spacecraft designer during the development process indentify the most useful set of telemetry points for TT+, (2) to help the test engineer validate performance against traditional software simulations and hardware prototypes, (3) to train and rehearse operators so a wide-variety of scenarios can be experienced interactively rather than a few pre-planned situations, and (4) to help the operator diagnose and correct complex, unexpected, anomalous situations.

      Gilje, Harold B.; Gravel, Arthur J.; AYDIN VECTOR DIVISION (International Foundation for Telemetering, 1989-11)
      The Telemetry Group of the Range Commanders Council has provided suggested standards for transmission of telemetry data. These standards were necessary to promote compatibility of operational equipment at the respective Test and Evaluation ranges. For digital transmission, the applicable standards define the frame and word formats necessary for range compatibility. These standards were developed for acquisition of multiple analog and bi-level signals and provided a relatively straight forward means of developing an aggregate, time-division multiplexed (TDM), serial, data stream which includes the information necessary to reconstruct the signals at the ground station prior to analysis. The Inter-Range Instrumentation Group (IRIG) formats are, by design, periodic and form a matrix of Awords@ which are preassigned to each and every signal being encoded and transmitted. As all the original information is continuous in nature, the encoder must sample each of the channels in their proper sequence and place the sampled data in it’s respecitve time slot. This paper will address some of the buffering techniques used to transmit data in an integrated IRIG format. We will then address an alternate solution to transmitting computer data for ground based analysis and processing, i.e., transmission of data using commercial type modems.

      O’CLARAY, DAN; TOBIN, HENRY; DATATAPE INCORPORATED (International Foundation for Telemetering, 1989-11)
      In order to satisfy future instrumentation data recording requirements, the availability of high data rate recorders with long record times is most desirable. Also, assurance of commonality amongst the many users of these data requires that any system designed be compatible across the user data base. Hence, the American National Standards Institute (ANSI) has developed a tape format standard that will assure commonality and exchange of data in an acceptable manner. This standard also establishes data rate recording requirements using a commercially available media in cassette form that will satisfy the operational need. DATATAPE is developing a recorder system that will meet the ANSI requirements of the data format on tape, as well as the data rate and record times implied by the standard. This paper discusses the development of the tape format standard and the design of the system that will fully comply with the standard. Test data will be presented to verify system capabilities. Additionally, DATATAPE’s progress in developing a system that will comply with the similar Department of Defense (DOD) tape format Standard, MIL-STD2179, will be presented, along with a summary of DOD programs that require MIL-STD-2179 compliant recorder systems.

      Dunn, Wiley E.; Fairchild Weston Systems Inc. (International Foundation for Telemetering, 1989-11)
      Although magnetic recording devices employing rotary head technology have been around for many years, specific products were not developed with the bit error performance to satisfy the instrumentation recorder needs of the telemetry community. Only recently have a number of new products and new product development programs materialized which offer positive indications that telemetry systems will soon benefit from the higher data rates and storage capacities. The lack of standards in development of rotary head technology has led to development of a variety of design approaches by various manufacturers and system designers. If this trend continues, the telemetry community will not enjoy the media compatibility which has contributed so much to the success of the IRIG instrumentation recorder. The ability to remove a tape recorded on one vendors recorder and replay the tape on a different ground station containing a second vendors recorder is a capability that should be retained with the advent of the new machines. Two standards have evolved defining tape characteristics and the format of information on tape for instrumentation rotary head recorders. For the instrumentation tape media to be truly transportable between telemetry ground stations, standard signal and data formal interfaces must also be developed.
    • Third-generation Advances in Thermal Printhead-based Chart Recorders

      Gaskill, Dave; Astro-Med, Inc. (International Foundation for Telemetering, 1989-11)
      A brief recap of the effect thermal printhead technology has had on the common 8-channel strip chart recorder, followed by a summary of second and third generation products and their envolving capabilities. How these new instruments are being accepted and used by telemetrists and ground station managers who are faced with bigger tasks and shrinking budgets. A study of how today’s telemetry professionals are shaping the 8-channel recorders of tomorrow, and the new capabilities they will bring.
    • Standard Services for the Capture, Processing, and Distribution of Packetized Telemetry Data

      Stallings, William H.; Goddard Space Flight Center (International Foundation for Telemetering, 1989-11)
      The Information Processing Division (IPD) at the Goddard Space Flight Center (GSFC) has the primary responsibility for the data capture, short-term storage, quality assurance and accounting, pre-processing, and distribution of telemetry data from numerous National Aeronautics and Space Administration (NASA) spacecraft missions. This functional service is referred to as level 0 processing. Level 0 processing is differentiated from higher level processing in that the functions performed do not change the raw sensor or supporting data received and extracted from the telemetry streams (1). Error correction processing and the filling of data gaps to maintain continuity are included functions where applicable. Currently there are two basic forms of telemetry utilized by spacecraft missions supported by level 0 processing systems in the IPD; time division multiplexed and packetized. The basic processing services provided by these systems which are very similar have evolved over many years through experience with numerous spacecraft missions and differing user requirements. The goal of reducing the end-to-end information data system complexity and developmental and operational costs has led to the current extensive effort to standardize data formats utilized by spacecraft missions as well as the user services provided. It has been shown that the use of packetized telemetry will significantly reduce costs while enhancing service for future missions. Packet telemetry standards consistent with the international Consultative Committee for Space Data Standards (CCSDS) are being developed which will provide the basis for future mission data system implementations (2). The IPD has developed two facilities which provide level 0 processing for missions utilizing packetization; the Hubble Space Telescope (HST) Data Capture Facility (DCF) and the Packet Processor (Pacor). The HST DCF, a dedicated system, was the first to be developed and provided the basis for the development of the multimission Pacor DCF. The Pacor is currently capable of providing the processing for the Gamma Ray Observatory and other missions using non-standard packet formats and future missions using standard packet formats compatible with the CCSDS recommendations. Through the development of the packet processing systems, which included extensive working with users, standard level 0 processing functions and services evolved. It is felt that these functions and services form the basis for future implementations including those for the Space Station Freedom. This paper will detail these functions and services.
    • Single Board Bit Synchronizer

      Burgess, George; Bridges, Lloyd; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1989-11)
      ASIC developments have made it possible to include the essential signal processing functions for data detection, clock recovery, and NCO in a single custom-designed chip. Using this chip and PLDs enabled the implementation of a fully-featured bit synchronizer on a single VME board in a rack-mountable 1.75" high, 19" wide chassis. This represents a space savings of 2/3 over existing units. The data rates supported are 250 bps to 5Mbps (2.5 Mbps biphase).
    • The Rotor-Signal-Module of MFI90

      Holland, Rainer; DLR Institut für Flugmechanik (International Foundation for Telemetering, 1989-11)
      This paper presents special measuring equipment designed for acquiring rotor data from a BO105 helicopter. Some aspects of hardware design, especially in the field of digital data acquisition and processing will be discussed. On this occasion the limited space available on the rotor hub must be taken into consideration. The rotor-signal-module also has to function in the future measurement system MF190. The paper concludes with the presentation of a method of calibrating the measurement values from the rotor blades. In this connection measured rotor data will be compared with results obtained by a nonlinear helicopter computer simulation. This represents one possibility to check the data quality.
    • Small Intercontinental Ballistic Missile Telemetry Processing System

      Woodham, Milt; Kelley, A. L.; Martin Marietta Corporation; Fairchild Weston Data Systems (International Foundation for Telemetering, 1989-11)
      Development of the Small Intercontinental Ballistic Missile (SICBM) requires a versatile Telemetry Processing System to support the various tests throughout the development. These test requirements created a need for high-speed data processing and display for real time decisions. These requirements were driven by the need to reduce development time and cost of the small ICBM. Martin Marietta was also interested in an off-the-shelf system (hardware and software). The system had to be menu-driven and user-friendly. Martin Marietta entered into a contract with Fairchild Weston Systems Inc. to supply five (5) of these systems, known as Telemetry Processing Systems (TPS). This paper defines the TPS System hardware and software capabilities and how it is being used to support the small ICBM testing.
    • A Time-Variant Approach for Encrypted Digital Communications

      Ng, Wai-Hung; The Aerospace Corporation (International Foundation for Telemetering, 1989-11)
      Two new approaches, a time-variant key and a random transmission rate, are introduced to strengthen the security of encrypted digital communications in which a "black-box" type of crypto-device is employed. These approaches not only further upgrade present crypto-methodology, but may also secure the system against the possibility of the cryptographic key's falling into the hands of an unauthorized listener after initial communication has begun. Therefore, communication privacy could be maintained even under the most scrutinizing post-recorded ciphertext attack.
    • Simulated Performance Results of the OMV Video Compression Telemetry System

      Ingels, Frank; Parker, Glenn; Thomas, Lee Ann; Mississippi State University; Marshall Space Flight Center, NASA (International Foundation for Telemetering, 1989-11)
      The Orbital Maneuverable Vehicle (OMV) will use a man-in-the-loop round trip space-to-earth communication link for remote control and docking with an orbiting spacecraft. The control system uses range/range rate radar, a forward command link, and a compressed video return link. Figure 1 illustrates the overall compressed video coding techniques. Analog RS-170 compatible video is available from any one of eight or, at a lower resolution, simultaneously from any two television cameras. The video data is digitized and then compressed by sampling every sixth frame of data. A rate of five frames per second is adequate for the OMV docking speeds. Further compression, at the expense of spatial resolution, is obtained by averaging adjacent pixels. The remaining compression is achieved using differential pulse code modulation (DPCM) and Huffman run length encoding. To protect this compressed video data stream from Space to TDRSS channel errors, a concatenated error correction coding system will be used. This concatenated coding is achieved by encoding with a helical interleaved (depth 8) Reed-Solomon (255,239) block code and then encoding with a rate 112 convolution code (constraint length 7) followed by a periodic convolution interleaver (30,116). Thus, we see that four stages of compression, two types of error correction encoding and two levels of interleaving are utilized in this fairly sophisticated data transmission system. A detailed system description and simulated system performance results are presented in this paper.

      Wargo, William D.; Watt, Gill; Metraplex Corporation (International Foundation for Telemetering, 1989-11)
      This paper will address the application of an end-to-end programmable PCM telemetry system featuring a modular, programmable data acquisition and encoding system, and a data analysis work station using an IBM PC compatible computer.
    • Subminiature Telemetry Systems For Submunitions

      Renken, G.; Ferguson, D.; Havey, G.; Kriz, J.; Olson, R.; Honeywell Sysytems and Research Center (International Foundation for Telemetering, 1989-11)
      The increased sophistication and reduced size of the emerging generation of ‘smart’ submunitions has generated a requirement for subminiature telemetry systems for use in test and evaluation. The Army’s SADARM and the Air Force’s Sensor Fuzed Weapon (SFW) are typical of smart submunitions with multiple sensors, VHSIC signal processing, large warheads, and complex deployment sequences. Reported here is the SADARM Telemetry Module, designed and developed by Honeywell to support the SADARM Program. The SADARM Telemetry Module applies MMIC and VLSI technology to provide sophisticated telemetry operation with a physically small, (2 in ) package, in a harsh operating environment. The 3 SADARM Telemetry Module senses 17 channels of digital and analog data, digitizes the analog data, multiplexes and PCM formats the data stream and transmits it via an IRIG compatible MMIC transmitter. This SADARM Telemetry Module was used to collect in-flight performance data at the SADARM Congressional Tests in February, 1989. Submunitions have evolved into very complex systems. Submunition development support testing has also become increasingly complicated. Onboard flight recorders are not feasible for live submunition tests because destruction of the submunition after the test precludes recovery of the recorded data. Telemetry provides the necessary test and measurement support required for efficient, cost effective, submunition development. The application of conventional telemetry for this type of submunition instrumentation has also become more difficult as the submunitions have become smaller in size and have more complex deployment sequences to evaluate. In addition, subminiature telemetry provides a practical, cost effective means to support field testing and development efforts in multiple munition weapon systems. In fact, subminiature telemetry offers the most practical instrumentation approach to evaluate the in-flight performance of several munitions dropped simultaneously. The SADARM Telemetry Module, discussed in this paper, incorporated these subminiature telemetry performance requirements into a practical, cost effective instrumentation package for SADARM development support.
    • Specifying and Evaluating PCM Bit Synchronizers

      Carlson, John R.; Aydin Computer and Monitor Division (International Foundation for Telemetering, 1989-11)
      As we enter the 1990’s PCM Bit Synchronizers continue to be of major importance to data recovery systems. This paper explains the specification of PCM Bit Synchronizers and provides insight into real world performance requirements and verification methods. Topics include: Theoretical bit error ratio for wideband versus prefiltered data, probability of cycle slip, jitter, transitition density and transition gaps. The merits of multiple and/or adaptive, loop bandwidth, input signal dynamic range, and embedded Viterbi decoders are also discussed. Emphasis is on the new high data rate applications, but the concepts apply to the specification of bit synchronizers in general.

      LaPlante, John R.; Barge, Steve G.; Loral Instrumentation (International Foundation for Telemetering, 1989-11)
      The difficulty of incorporating custom real-time processing into a conventional telemetry system frustrates many design engineers. Custom algorithms such as data compression/conversion, software decommutation, signal processing or sensitive defense related algorithms, are often executed on expensive and timeconsuming mainframe computers during post-processing. The cost to implement such algorithms on real-time hardware is greater, because programming for such hardware is usually done in assembly language or microcode, resulting in: The need for specially trained software specialists Long and often unpredictable development time Poor maintainability Non-portability to new applications or hardware This paper presents an alternative to host-based, post-processing telemetry systems. The Loral System 500 offers an easy to use, high-level language programming environment that couples real-time performance with fast development time, portability and easy maintenance. Targeted to Weltek’s XL-Serles 32 and 64 bit floating point processors, delivering 20 MFLOPS peak performance, the environment transparently integrates the C programming environment with a parallel date-flow telemetry processing architecture. Supporting automatic human interface generation, symbolic high-level debugging and a complete floating point math library the System 500 programming environment extends to parallel execution transparently. It handles process scheduling, memory management and data conversion automatically. Configured to run under UNIX, the system’s development environment is powerful and portable. The platform can be migrated to PC’s and other hosts, facilitating eventual integration with an array of standard off-the-shelf tools.

      Burgess, George; Bridges, Lloyd; Stanford Telecommunications, Inc. (International Foundation for Telemetering, 1989-11)
      ASIC developments have made it possible to include the essential signal processing functions for data detection, clock recovery, and NCO in a single custom-designed chip. Using this chip and PLDs enabled the implementation of a fully-featured bit synchronizer on a single VME board in a rack-mountable 1.75" high, 19" wide chassis. This represents a space savings of 2/3 over existing units. The data rates supported are 250 bps to 5Mbps (2.5 Mbps biphase).