Tubbs, Casey; SCI Technology, Inc. (International Foundation for Telemetering, 1990-11)
      Asynchronous data sources such as those associated with Space Based Radar create a unique problem for Time Division Multiplexed (TDM) Pulse Code Modulation (PCM) frame formats. The problem consists of data arrival based on external occurrences such as target tracking, and not due to sampling polls from internal sequencers. Reserved time slots for asynchronous data must be provided within the synchronous TDM telemetry stream. This increases the required bandwidth to transfer collected data to ground sites proportional to the worst case arrival rate of asynchronous data and the maximum latency allowed for the application. Asynchronous data is readily handled by the Consultative Committee for Space Data Systems (CCSDS) recommended formats without the need to increase the bandwidth disproportionately. The recommendation maintains the ability to provide synchronous telemetry data collection and transmission provided by the TDM PCM frame formats. This paper provides an implementation of CCSDS recommendations and addresses the methodology of merging asynchronous and synchronous data sources without the prerequisite increase in bandwidth associated with purely synchronous TDM approaches. Additional implementation details are provided for the implementation of a Telemetry Operation Procedure (TOP) to downlink error free telemetry frames. The TOP is not currently supported within the CCSDS recommendation. The implementation is provided through the Micro Packaged Data Acquisition and Control Systems developed by SCI Technology in Huntsville, Alabama.
    • Telemetry Format Compiler for the Generation of State machine Code Executed by a PCX Encoder

      Landry, Michael; Loral Conic (International Foundation for Telemetering, 1990-11)
      Telemetry encoders commonly use programmable memory devices for the storage of data used to control the multiplexed output format. The manual generation of this program control information is tedious and error prone. A telemetry format compiler has been developed to automate this process. A high level definition of the format information is processed to result in a binary object file which is programmed into the memory of the encoder and executed by the state machine controlling the encoding.

      Berdugo, Albert; Ricker, William G.; Aydin Vector Division (International Foundation for Telemetering, 1990-11)
      Increased data throughput demands in military and avionics systems has led to the development of an advanced, All-Bus MIL-STD-1553 Instrumentation Monitor. This paper discusses an airborne unit which acquires the information from up to 8 dual-redundant buses, and formats the data for telemetry, recording or real-time analysis according to the requirements of IRIG-106-86, Chapter 8. The ALBUS-1553 acquires all or selected 1553 messages which are formatted into IRIG-compatible serial data stream outputs. Data is time tagged to microsecond resolution. The unit selectively transmits entire or partial 1553 messages under program control. This results in reduced transmission bandwidth if prior knowledge of 1553 traffic is known. The ALBUS also encodes analog voice inputs, discrete userword inputs and multiplexed analog (overhead) inputs. The unit is provided in a ruggedized airborne housing utilizing standard ATR packaging,

      DeWaters, Ronald; Anderson, William; Naval Surface Warfare Center; Loral Data Systems (International Foundation for Telemetering, 1990-11)
      In 1986 the Navy procured Automatic Engineering Read Out (AERO) Telemetry Test Systems to receive, record, process and display telemetry data transmitted from SM-1 and SM-2 STANDARD missiles. AERO systems are self-contained data acquisition systems which are portable for field use, and are capable of receiving missile data, recording the data on analog tape, decommutating data into a computer compatible format, recording data on disk, and displaying processed data on the operator’s terminal. The original design was intended to be versatile and to accommodate future telemeters through software programming, signal switching, unit/module substitution, or add-on equipment. Original missile formats included data rates up to 50,000 data words per second. AERO systems have been used to support field testing of Navy missiles since 1987. In 1989 the AERO system requirements were changed to include support for a new STANDARD missile telemeter which transmits data at much higher rates. The AERO systems have been upgraded to support the new requirement by replacing I/O modules in the host computer, and modifying the control software. The modified system, which is hosted by a low cost DEC MicroVAX computer, records 100 percent of the telemeter data on disk at rates up to 600,000 bytes (300,000 data words) per second, and displays results for quick look review immediately after the missile test. This paper discusses the requirements for the AERO systems, the design philosophy used to ensure an upgradable path, and the benefits of that philosophy when an upgrade was required. The upgrade itself is significant because a low cost MicroVAX has been adapted to a high performance application. The AERO systems were designed, developed and upgraded by Loral Data Systems (formerly Fairchild Weston Data Systems) to the specifications of the Naval Surface Warfare Center in Dahlgren, Virginia.

      McGiven, Fred A.; TIW Systems Inc. (International Foundation for Telemetering, 1990-11)
      TIW Systems has developed a modern, compact, modular, antenna controller (ACU) for telemetry, tracking, and communications antennas. The controller combines the functions of an antenna control unit, a position conversion/display chassis, and a polarization control unit. By using plug-in cards, a tracking receiver, autophasing control unit, tracking synthesizer, and other functions can be added. Depending on the requirements, the tracking receiver can be a simple wide-band steptrack receiver, or can be a full function phase-locked-loop (PLL) autotrack receiver. In the past, all this capability would have taken a large portion of an entire equipment rack. The unit uses modern microprocessor technology for digitally controlling the position and rate of the antenna. Advanced tracking modes and remote control can be added by connecting an external computer (PTIC) to one of the ACU’s serial ports. The PTIC also provides a user friendly operator interface through the use of high resolution color graphics and easy to understand menus.

      Cipolla, Frank; Seck, Gerry; Datron Systems Inc. (International Foundation for Telemetering, 1990-11)
      Datron Systems Inc. has developed a high efficiency autotrack feed series which uses a tracking mode coupler to generate track error signals. The mode coupler allows the use of a corrugated feed horn in doubly shaped or cassegrain geometries or a scaler ring feed in prime focus reflectors, to achieve extremely high overall antenna efficiencies. The low insertion loss of the mode coupler allows the incorporation of autotrack capability in an antenna system without degradation of the overall G/T or EIRP. Another feature of this feed is the excellent cross talk performance. The mode coupler is a rho-theta type tracker and as such is suitable for use in both single channel monopulse and equivalent full three channel monopulse autotrack applications. Datron has built, installed, and tested feeds of this type at S, C, and X band frequencies and is currently under contract to develop a dual K/Q band version. Datron has also integrated other components into the mode coupler feed assembly such as: amplifiers, filters, diplexers, couplers, downconverters, switches, noise sources, etc.

      COOK, JAMES H., JR.; KOSTER, A. RENEE; SCIENTIFIC-ATLANTA, INC. (International Foundation for Telemetering, 1990-11)
      The design and performance of a 1435 MHZ to 2600 MHZ ESCAN1 feed will be discussed. The radiation characteristics of a very small (<10 wavelengths) reflector antenna will be presented. The ESCAN tracking concept offers a significant improvement in the effective gain, sidelobes and tracking performance for broadband telemetry trackers over previous, low-cost approaches. The tradeoffs associated with the optimization of the ESCAN antenna’s radiation performance will be presented along with a comparison of conical scan and single channel monopulse performance. The tradeoffs will include an analysis of the limitations in performance due to central blockage, aperture illumination, spillover, and coma effects of an “effective” off-axis feed for a small, paraboloidal reflector antenna.
    • Frame Synchronization At 300 Mbps And Beyond ...

      Wunderlich, Kristin; Chesney, Jim; Bennett, Toby; Goddard Space Flight Center; Ford Aerospace Corporation (International Foundation for Telemetering, 1990-11)
      While most current ground based space telemetry acquisition systems are designed for and support data rates up to a few megabits per second (Mbps), NASA’s Tracking and Data Relay Satellite System (TDRSS) can support downlink rates up to 300 Mbps. In addition, the Advanced TDRSS (ATDRSS) is expected to support rates up to 650 Mbps. These high data rates will be required to support NASA’s future large scale operational programs such as the Space Station Freedom and the Earth Observation System. At the Goddard Space Flight Center, a prototype Frame Synchronizer card is under development which will operate at a minimum of 300 Mbps while providing a full suite of programmable functions such as 32 bit correlation, search-check-lock strategy, bit slip tolerance, fly wheeling, etc. In addition, cumulative quality data generation, on-board self diagnostics, and status/control processing are all integrated in this single card design. This level of functionality and very high data rate is made possible by the design of NASA application specific Gallium Arsenide (GaAs) Very Large Scale Integrated (VLSI) circuits to support space telemetry data system standards specified by the Consultative Committee for Space Data Systems. This paper will describe functions performed by this card and its supporting VLSI components.
    • Telemetry Antenna Patterns for Single and Multi-Element Arrays

      Rieger, James L.; Naval Weapons Center, China Lake, California (International Foundation for Telemetering, 1990-11)
      The use of multiple antennas (or multiport) antennas for vehicular telemetry causes patterns to result which are unknown and not well understood by the telemetry designer. When the antenna ports are separated by distances of more than a half wavelength, the resulting patterns are rarely what was intended. The antenna plotting program, an extension of a earlier University of Utah antenna plotting routine, allows rapid creation of patterns for up to 30 (or more) antennas of like polarization displaced from each other in all three axes. Single-port antennas are modeled as compound antennas to produce the observed pattern, and combinations of these single-port antennas are then plotted. Case studies are shown for an aircraft and a missile body.

      Perry, Ross; Kelly, Fred; Brimbal, Michel; Computer Sciences Corp.; Gould Inc. (International Foundation for Telemetering, 1990-11)
      The Telemetry Integrated Processing System (TIPS) at the U.S. Air Force Western Space and Missile Center (WSMC), Vandenberg AFB, California is a large scale, computer based, telemetry processing and display system installed in the early 80’s. The digital printer/plotters used in the Quick Look Display Area (QLDA) were installed in 1979 and their maintenance support has become critical. Their replacement is now necessary. This paper will present the approach used to solve the replacement of these printer/plotters by off-the shelf commercial equipment. The key objectives of providing users with a similar display output and strict hardware and software compatibility with existing system have been met. In addition, the new equipment installed can meet the display requirements of future developments or upgrades of the TIPS.

      Robillard, Jean-Claude; Brimbal, Michel; Gould Inc., Array Recorders Division; Gould Inc., Recording Systems Division (International Foundation for Telemetering, 1990-11)
      In the past 2 to 3 years, linear array recorders based on direct thermal printing technology have proven to be the recorders of choice for a large number of telemetry display stations. This technology initially developed for facsimile communications has evolved to meet speed and reliability required by the operation of recorders in the telemetry station environment. This paper discusses the performance of various direct thermal printing techniques employed. The focus is given to parameters that are critical to telemetry station operation such as quality of the chart output, maintenance and support, reliability and cost. The reliability issue is discussed at length as it is impacted by printhead thermal stress and mechanical wear. Other printing technologies available for chart recording are briefly reviewed as they may appear to be suitable alternatives in some telemetry applications.

      Malone, Erle W.; Breedlove, Phillip; Boeing Aerospace, Seattle, WA; Loral Conic, San Diego, CA (International Foundation for Telemetering, 1990-11)
      A telemetry system which integrates MIL-STD-1553 bus data, dual-simplex bus data, vehicle performance data, and environmental sensor data multiplexing involves many interfacing constraints. The engineering design considerations and hardware constraints required to implement this system are presented in this paper.

      Deutermann, Alan; Schaphorst, Richard; Delta Information Systems, Inc. (International Foundation for Telemetering, 1990-11)
      As the role of television in the aerospace industry has expanded so has the need for video telemetry. In most cases it is important that the video signal be encrypted due to the sensitive nature of the data. Since this means that the signal must be transmitted in digital form, video compression technology must be employed to minimize the transmitted bit rate while maintaining the picture quality at an acceptable level. The basic compression technique which has been employed recently, with successful results, is a combination of Differential PCM and Variable Length coding (DPCM/VLC). This technique has been proposed to the Range Commanders Council to become a possible standard. The purpose of this paper is to compare the basic DPCM/VLC technique with alternative coding technologies. Alternative compression techniques which will be reviewed include Transform coding, Vector Quantization, and Bit Plane coding. All candidate techniques will be viewed as containing four elements -- signal conditioning, signal processing, quantization, and variable length coding. All four techniques will be evaluated and compared from the stand point of compression ratio and picture quality.

      Quart, Barry; Mitchell, Rick; Bombardier Inc.; Loral Data Systems (International Foundation for Telemetering, 1990-11)
      The Data Acquisition System Ground Station (DASGS) is a system developed by Loral Data Systems (Loral) for CANADAIR Aerospace Group. The system implements the latest technologies in telemetry front-end equipment, host computers, networking, and graphic workstations. The goal of the DASGS is to supply Canadair with a telemetry acquisition and processing system that can satisfy the Regional Jet (RJ) program requirements and provide future expandability to service their needs throughout the 1990’s. This paper will address three aspects of this telemetry system. First, the telemetry data processing requirements of the RJ program will be described. Second, the system architecture, both hardware and software, will be discussed and the basis for the architecture. The third topic of this paper will cover how the system processing capability can be increased to satisfy Canadair’s future requirements.

      Strock, O. J. (Jud); Witchey, Michael (Mike); Loral Data Systems (International Foundation for Telemetering, 1990-11)
      This paper responds to a test range engineer’s need to relay one or more channels of various types of telemetry data from a remotely-located receiving station to the central telemetry station at range headquarters for real time processing and display. Several types of data are identified, and specific equipment and technology for multiplexing, transmission, and demultiplexing up to eight streams from a variety of sources is discussed. The widely-used T3 communications link, also known as DS-3, can relay data via satellite, microwave link, or other high-speed path at 44.736 megabits per second, of which about 95% can be actual telemetry data; other standard links operate at lower aggregate rates. Several links and rates are discussed, with emphasis in the high-rate T3 link.

      SMITH, DARREN C.; CHINA LAKE NAVAL WEAPONS CENTER (International Foundation for Telemetering, 1990-11)
      The Naval Weapons Center (NWC) A-6E flight test program, like so many DOD efforts, is caught in the vise of declining budgets and increasing demands and requirements. The A-6E data management system has evolved over 30 years by extensive testing and reflects all the “real world” experience obtained over that period of time. This paper will address that data management system, specifically how data is recorded on the A-6E during flight test and some associated issues as well as how that data is managed for analysis use, all within the environment of tight budgets and increased requirements.

      Wechel, Robert Van; Interstate Electronics Corporation (International Foundation for Telemetering, 1990-11)
      The GPS equipment developed in the tri-service GPS range applications program is now available for use. One promising application on test and training ranges is for pointing control of theodolites, laser trackers, and threat emitters. Theodolites and laser trackers are capable of extremely high accuracy in range applications, but suffer from a very narrow acquisition range, thus requiring external acquisition aiding. Unmanned threat emitters are also used that require external pointing information. In this application of GPS, a GPS receiver or translator is used on the test or training vehicle, and the position of the vehicle is downlinked to the tracking site. A pointing angle is then computed at the tracking site and is used to point or steer the theodolite, laser tracker, or threat emitter. Because of the high accuracy, of differential GPS, this method is very precise. Also, with a direct high-rate datalink, time delays for the pointing information can be very low, again providing very accurate pointing for high-dynamic vehicles. This method promises to be a highly cost-effective approach for steering these devices because it eliminates the requirement for continuous manning of the sites.
    • Optical Communication in Space A Challenge to Microwave Links

      Mayer, Gerhard; Franz, Jürgen; Applied Data Systems Division; Institute for Communication Technologies (International Foundation for Telemetering, 1990-11)
      Laser communications offer a viable alternative to microwave communications for intersatellite and interplanetary links. Main characteristics are higher data rates, small size antenna telescopes with narrow beamwidths, but the drawback of the necessity for complex pointing, acquisition and tracking systems. After a review of some important technology aspects and modulation / detection schemes the optospecific link parameters axe discussed. An experimental coherent optical system set-up at DLR is described.

      Penna, Sergio Duarte; EMBRAER - Flight Test Division (International Foundation for Telemetering, 1990-11)
      The 90’s will be a challenge to many industries, but in particular to airframe manufacturers like EMBRAER that wish to grow up on a solid basis not only for this decade, but also for the next one. This paper describes the requirements of the on-board data acquisition system and alternatives proposed for the EMBRAER’s new 19-seat, twin engine turbo prop commuter aircraft, the CBA-123.

      Napier, T. M.; Peloso, R.A.; Aydin Computer and Monitor Division (International Foundation for Telemetering, 1990-11)
      An innovative digital approach to analog noise synthesis is described. This method can be used to test bit synchronizers and other communications equipment over a wide range of data rates. A generator has been built which has a constant RMS output voltage and a well-defined, closely Gaussian amplitude distribution. Its frequency spectrum is flat within 0.3 dB from dc to an upper limit which can be varied from 1 Hz to over 100 MHz. Both simulation and practical measurement have confirmed that this generator can verify the performance of bit synchronizers with respect to the standard error rate curve.