• Use of a Commercial Visual Programming Language to Simulate, Decommutate, Test and Display a Telemetry Stream

      Wells, George; Baroth, Ed; California Institute of Technology (International Foundation for Telemetering, 1994-10)
      The advantages of using visual programming to create, modify, test and display a telemetry stream are presented. The failure to fully deploy the high-gain antenna of the Galileo spacecraft has resulted in a software redesign of the computer systems onboard the spacecraft to support the low-gain antenna mission. Visual programming software is being used to test new algorithms as part of the ground support for the spacecraft Test Bed. It is very important that any new software algorithms be thoroughly tested on the ground before any modifications are made to the spacecraft. The advantage of using a visual programming language (LabVIEW, National Instruments) is that it provides easy visibility into the decommutation process that is being modified by the Galileo programming support team. In addition, utilities were written using visual programming to allow real-time data display and error detection. A data acquisition board is used to clock in the actual synchronous telemetry signal from the Test Bed at rates below 10 kHz. The time to write and modify the code using visual programming is significantly less (by a factor of 4 to 10) than using text-based code. The gains in productivity are attributed to the communication among the customer, developer, and computer that are facilitated by the visual syntax of the language.
    • The Use of Digital Signal Processors in Front-End Weather Satellite Telemetry Processing

      Lide, David A.; Talabac, Stephen (International Foundation for Telemetering, 1994-10)
      This paper discusses the use of DSP technology in the embedded real time ingest and pre-processing of weather satellite data. Specifically, case studies are presented in the use of Texas Instrument TMS 320 processors as front-end handlers of GOES MODE AAA and GOES GVAR data formats.
    • The Use of Open Architecture Systems in Cost Reduced Satellite Telemetry & Control Stations

      Spielman, David R.; AP Labs, Inc. (International Foundation for Telemetering, 1994-10)
      A comprehensive examination of the market demands for cost reduced satellite telemetry & control stations will be presented. These systems are implemented using flexible, open architecture-based high performance real-time systems. The trend for combining telemetry monitoring of satellite data with closed-loop satellite command and control functions will be presented. This combined functionality opens up the possibilities for completely integrated, reduced cost satellite control systems. The market forces driving the demand for this integrated functionality include the broadening of non-military satellite applications, the widening international deployment of commercial satellites and the accompanying drive toward decentralized satellite control. The major requirements for the telemetry processing and command & control functionality of the integrated, reduced cost satellite control system will be presented. These requirements include: full real-time performance for processing telemetry data; flexible architecture for the incorporation of a wide range of I/O devices; capability of performing real-time, closed-loop control based on conditions in the telemetry data; user friendly development environments for application-specific customization of the system; and low system costs with the capability of indigenous support. The divergent requirements of performance, flexibility and price of these integrated, reduced cost satellite control systems is made possible via the use of open architecture building blocks that include standard VME boards combined with specialized real-time software drivers and user oriented, flexible Graphical User Interface (GUI) software.
    • Variable Polarization Ferrite Antenna

      Dunn, Daniel S.; Telep, Matthew S.; Augustin, Eugene P.; Technical Systems Associates, Inc (International Foundation for Telemetering, 1994-10)
      This paper describes a ferrite antenna that can produce any polarization on the Poincaré sphere over the frequency range of 9.0 to 11.4 GHz by utilizing Faraday rotation and a quarter-wavelength phase shifter. All possible polarizations of the electromagnetic wave are achievable with this antenna which includes linear, circular and elliptical polarizations. Any tilt angle of elliptical polarization and any orientation of the linear polarization can be achieved as well. The polarization of the ferrite antenna can be electronically switched to a different polarization instantly without the use of moving parts. An automatic data acquisition system was designed and built to fully analyze the antenna' s characteristics.
    • VERIFICATION AND VALIDATION OF CONTROL CENTER OPERATIONS USING A TELEMETRY SIMULATION

      Policella, Joseph; Kleen, Mitchell; White, Joey; CAE-Link Corporation (International Foundation for Telemetering, 1994-10)
      In space applications, telemetry systems are traditionally used to provide a front end for processing Control Center data. Control Center operations dictate the content and processing requirements of the telemetry data to enable the control center personnel to make proper decisions concerning the operation of their space vehicle. Unfortunately many anomalous operational scenarios do not arise during control center checkout procedures which are designed to test the functionality of the Control Center equipment. However, an interactive telemetry simulation, which involves producing telemetry data using real-world formats and data rates, can create many of the situations control center personnel may encounter. A host computer is used to drive a telemetry system which in turn produces simulated vehicle data. As a result, a telemetry simulation can not only verify the functionality of the Control Center hardware and software, but also validate Control Center procedures and train Control Center personnel in the process.
    • Voice Encode/Decode System for PCM Insertion and Extraction

      Laird, Daniel T.; Edwards Air Force Base (International Foundation for Telemetering, 1994-10)
      In the field of aircraft testing the need to efficiently record the cockpit voice communication without consuming a significant amount of the acquisition frame bandwidth has been an issue for years. There are methods, based on commercially available products, that allow for voice placement into PCM streams that will satisfy the requirement of relatively low bandwidth consumption. In this paper I will discuss a design that makes minimal demand on bandwidth, with the freedom to vary the placement of the voice within the minor acquisition frame.
    • Wideband FM Telemetry Application

      Neuens, Jim; Veda Incorporated (International Foundation for Telemetering, 1994-10)
      A Wideband FM Telemetry System was developed by Veda Incorporated and Boeing Commercial Airplane. This system supports Boeing 777 flight testing and will support future Boeing test efforts. This is an upgrade to the system previously used by Boeing for testing other planes. The design interfaces to the new Boeing Data Acquisition and Analysis systems and provides 15 Megabits per second Telemetry at ranges up to 180 miles. This paper provides details regarding the following design and integration issues: o) RF Transmitter Design o) RF Receivers o) Airborne Antenna o) Ground Based Antenna o) Data Interfaces o) System Performance o) Problems / Solutions
    • XL-L: A Novel Two Axis Pedestal System Which Eliminates Keyholes and Has Complete Continuous Hemispherical Coverage Without the Use of Rotary Joints or Sliprings

      Augustin, Eugene P.; Sullivan, Arthur (International Foundation for Telemetering, 1994-10)
      The XL-L Two-axis Pedestal is a novel adaptation of an existing design using a cross elevation over elevation axis configuration. This design affords full hemispherical coverage without gimbal lock (keyholes). In addition, the system provides continuous coverage without the necessity of rotary joints and sliprings. The design is ideally suited for shipboard systems, but is equally advantageous for any tracking mission where the target can approach a zenith gimbal lock or keyhole.