• The Generic Data Capture Facility

      Connell, Edward B.; Barnes, William P.; Stallings, William H.; Goddard Space Flight Center (International Foundation for Telemetering, 1987-10)
      The growing complexity of space science missions is causing a dramatic increase in the data rates and volumes from spaced-based experiments, and the ground operations functions associated with handling data from these missions are growing in complexity consistent with this increase. A key requirement on the systems that provide data handling support is to control operations costs carefully while providing high-quality data capture functions. One approach to meeting this particular objective that has been taken at the Goddard Space Flight Center has been to initiate the development of a Generic Data Capture Facility (GDCF) that can provide data capture support for a variety of different types of spacecraft. The GDCF is emerging through a blend of new system development and evolution of existing systems, and when complete, it will have the capability to support the two major data formatting schemes (packet and Time-Division Multiplexed (TDM)). The specific implementations are designed to support the Gamma Ray Observatory and the Upper Atmosphere Research Satellite, but the GDCF will provide the baseline system to support various new missions as they emerge.
    • High Data Rate Reed-Solomon Encoding and Decoding Using VLSI Technology

      Miller, Warner; Moakis, James; Goddard Space Flight Center (International Foundation for Telemetering, 1987-10)
      Presented as an implementation of a Reed-Solomon encoder and decoder, which is 16-symbol error correcting, each symbol is 8 bits. This Reed-Solomon (RS) code is an efficient error correcting code that the National Aeronautics and Space Administration (NASA) will use in future space communications missions. A Very Large Scale Integration (VLSI) implementation of the encoder and decoder accepts data rates up to 80 Mbps. A total of seven chips are needed for the decoder (four of the seven decoding chips are customized using 3Fm Complementary Metal Oxide Semiconduction (CMOS) technology) and one chip is required for the encoder. The decoder operates with the symbol clock being the system clock for the chip set. Approximately 1.65 billion Galois Field (GF) operations per second are achieved with the decoder chip set and 640 MOPS are achieved with the encoder chip.
    • An Inexpensive S-Band Angle Pointing Technique for Steering a Narrow Beam Ku-Band Antenna

      Line, Larry; Hager, Fred; Hanson, Duke; Kral, Kevin; Moss, Robert; Goddard Space Flight Center; Motorola, Inc.; Honeywell-Speery Space Systems; Westinghouse Electric Corporation (International Foundation for Telemetering, 1987-10)
      A recently tested antenna pointing control system for gimbaled antennas has been developed. A modified TDRSS user transponder produces pointing error signals from the S-band forward link which in turn drive the Steering Control Electronics (SCE) to precision steer a S-/Ku-band Data and S-band Tracking (KDST) planar array. A successful test of the pointing and data handling capabilities is described and plans for further tests, incorporating additional refinements, are presented.
    • TDRS Ku-Band Gateway

      Collins, Cynthia M.; Lecha, Javier; Principe, Caleb M.; Ross, Douglas; Goddard Space Flight Center (International Foundation for Telemetering, 1987-10)
      The Wideband Transport Frame Formatter (WTFF) is the Tracking and Data Relay Satellite (TDRS) Ku-band return link gateway. This gateway is designed to support the Consultative Committee for Space Data Systems (CCSDS). The WTFF is being developed by Goddard Space Flight Center as a proof of concept project for the CCSDS and the National Aeronautics and Space Administration (NASA). This design is in many aspects consistent with the Open System Interconnect (ISO) model's "lower layer architecture". The WTFF system is a multiplexing device developed to process and downlink the high rate data generated by a wide variety of users. The WTFF is designed to frame and format high data rate user channels into transport frames and multiplex according to a predefined schedule into two bit streams that are compatible with TDRS Ku I and Q band service. The combined data rate will be 300 Mbps. The WTFF will service up to eight input channels generating data in the range of 10 to 150 Mbps. In addition to these input channels, audio data will be accepted by the WTFF system and inserted in the downlink. A second function of the WTFF is to provide telecommunication coding as assigned to each virtual channel to ensure a given quality of service.