• 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.
    • 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.
    • MIL-STD-1553 Data Acquisition System

      Landry, Michael; Loral Conic (International Foundation for Telemetering, 1989-11)
      The Range Commanders Council recently added a chapter to IRIG 106-86 which describes a standard for acquisition of MIL-STD-1553 traffic flow. A system has been developed which monitors bus traffic using the format described in the standard for encoding. In addition to bus data, PCM analog channels can be inserted into the telemetry steam. Due to the high bandwidth of the telemetry stream, real-time ground processing of the 1553 data is difficult. Therefore, a limited number of selective measurements taken from the bus traffic are available at fixed positions in the telemetry format for real-time monitoring of critical parameters. A discussion of hardware, software, encoding, and testing will be presented.
    • A GPS Disciplined Rubidium Clock

      Dewey, Wayne; Kinemetrics/TrueTime (International Foundation for Telemetering, 1989-11)
      Sub-Microsecond timing accuracy for event tagging and multisite synchronization is possible using the Global Positioning System. In order to maintain a high degree of accuracy during periods when no satellites are visible, a highly stable local time base is required. For those cases which require Cesium Oscillator stability, initial cost and continuing maintenance of the Cesium Oscillator must be considered. A viable alternative is attained by using the Global Positioning System and an oscillator disciplining process. With this system, near Cesium performance can be achieved using a more rugged lower cost Rubidium oscillator. Additionally, when 24 hour satellite coverage becomes available, system performance may surpass that of a Cesium in long term stability as well as long term drift. This presentation describes the system components, including Global Positioning System receiver, Miniaturized Controllable Rubidium Oscillator and Global Positioning System Clock. Clock timing accuracy and short and long term frequency stability results are discussed along with the control algorithms used in the disciplining process. A brief discussion of the computer modeling tools used is also presented.

      Daniels, R. Michael; Sandia National Laboratories (International Foundation for Telemetering, 1989-11)
      As a national laboratory, one of Sandia’s missions requires the development of airborne telemetry systems for acquisition and transmission of in-flight data and for control of flight vehicle functions. These telemetry systems are usually produced in small numbers and have very limited application. Before the flight test, systems undergo extensive functional and environmental testing. During the flight test, a method of sequencing through a predetermined flight program is required. To aid in the development of these telemetry systems, Controllers and Programmers have been developed. The telemeter uses an external Controller during functional and environmental testing to allow access to various internal telemeter functions. An on-board Programmer is used to manage the predetermined sequence of events throughout the flight test. Previously, such ControllerProgrammer systems have consisted of a single-purpose apparatus with limited scope. These systems would be re-designed with each telemetry system -- necessitating additional expenditures in manpower and hardware. This paper discusses an advanced Controller - Programmer system for telemetry applications. It is adaptable to a variety of telemeters and offers a number of benefits. The Controller has the ability to download flight sequence information to the Programmer via a serial communication link, even when the telemeter is assembled in the test vehicle. It also has the capability to log environmental test data and charge telemetry system batteries. Additionally, the Controller provides a user-friendly, reconfigurable method of command entry and a graphic display of telemetry parameters. The Programmer, in addition to communicating with the Controller, has the capability of flight sequence resumption after complete power failure via non-volatile storage of operating parameters. The programmer can control a virtually unlimited number of flight test functions yielding a high degree of design flexibility, and, being microcontroller based, is also power and space efficient.

      NAGARAJ, S.R.; RAJANGAM, R.K.; ISRO SATELLITE CENTRE (International Foundation for Telemetering, 1989-11)
      The Vector cardiography is the 3 dimensional study of Electrocardiographic responses of the human heart. A Vector cardiograph (VCG) instrument was designed and developed to monitor the Cardiographic responses of the Indian payload specialist under zero G conditions in the US Space Shuttle during the scheduled INSAT-lC launch. Accordingly the proposal made by Department of Space for using the vector cardiograph measurement in the Space Shuttle was accepted. A VCG unit was developed under the joint collaboration of HAL, Hyderabad and ISAC-ISRO. This paper brifly describes the design aspects of the VCG instrument, the qulification tests conducted on the same for space application and the final test results obtained during the process. Basically the instrument was built around a Hybrid Instrumentation amplifier and other interfaces for recording the signal into an audio taperecorder.

      CHAKRABORTY, S.K.; RAJANGAM, R.K.; ISRO SATELLITE CENTRE (International Foundation for Telemetering, 1989-11)
      The first Indian Remote Sensing Satellite was launched on 17th March 1988 from a Soviet Cosmodrome into a 904 Km Polar Sunsynchronous orbit. The data transmission from the satellite is at 5.2 Mega Bits/sec in S-Band and 10.4 Mega Bits/sec in X-Band. The payload data is formatted into custom made 8328 words format. A programmable unique versatile frame sync and Decommutation unit has been developed to test the data from the data handling system during its various phases of development. The system works upto 50 Mega Bits/sec and can handle frame sync code length upto 128 bits and a frame length of 2 Exp 20 bits. Provision has been made for programming the allowable bit errors as well as bit slippages, using a front panel setting. This paper describes the design and implementation of such a high bit rate frame synchroniser developed specially for IRS Spacecraft application. It will also highlight the performance of the system.
    • 1553 Data BUS/PCM Multiplexer System

      Breedlove, Phil; Malone, Earl; Loral/Conic; Boeing Aerospace (International Foundation for Telemetering, 1989-11)
      A Telemetry system which integrates 1553 Bus data, DualSimplex bus data, vehicle performance data, and environmental sensor data multiplexing encompasses many interfacing constraints. The Engineering design considerations and hardware constraints required to implement this system are presented in this paper.

      Havey, Gary; Tanji, Todd; Olson, Richard; Wald, Jerry; Honeywell Systems and Research Center (International Foundation for Telemetering, 1989-11)
      Honeywell, under contract from NASA Johnson Space Center and Lockheed Engineering and Sciences Company, has developed a new tool for instrumentation data collection. The Stand-Alone Pressure Measurement Device (SAPMD) is part of a family of microminiature data recorders combined with sensors that can be be used as flight development instrumentation on aerospace vehicles and structures. NASA came to Honeywell with a need to collect absolute pressure data during ascent of the Shuttle on various points over the orbiter’s surface. Instrumentation for this data does not exist on current orbiters, and NASA must use computer modeling to determine structural loading calculations. The conventional approach of placing sensors and cabling inside the Shuttle’s frame combined with drilling holes for the pressure sensors was considered too costly and could weaken the orbiter’s structure. The SAPMD measures pressure at various locations on the space shuttle orbiter skin during ascent. In order to avoid the extensive impacts associated with wiring new measurements into the orbiter data system, the device is self contained, incorporating its own sensor, power supply, self-starting sensor, nonvolatile memory for sensor data, and a real-time clock for time reference. The device is small enough (6.28 in x 1.5 in. x 0.5 in.) to be mounted under the thermal protection system tiles and rugged enough to withstand the environments encountered at the interface between tiles throughout an orbiter mission. Data recorded during ascent is recovered after the mission without removing the device. Other sensors such as strain gauges for structural monitoring, vibration gauges for wing flutter, or differential pressure gauges can be used with this hardware.
    • Amarrm Warhead Compatible Telemetry

      Powell, David G.; Pacific Missile Test Center (International Foundation for Telemetering, 1989-11)
      During the final stages of the AMRAAM Full Scale Development effort a requirement for a miniature warhead compatible instrumentation system was established. Internal missile volume was not available to house the system but volume was identified within the external wiring harness cover. The system was required to have significant data handling capability and encryption, and had to withstand a severe environment on a small power budget. Several technologies were developed at the Pacific Missile Test Center to meet this challenge including Application-Specific Integrated Circuits (ASIC), surface mount technology, and thick and thin film hybrid microcircuits. In addition the state-of-the art in transmitters and power converters was stretched. The result was an encrypted PCM telemeter with 2 watt transmitter and antenna all in the missile wiring harness cover (along with the wires!)

      VERHAEGHE, Jacques; Project Engineer, Techniphone, France (International Foundation for Telemetering, 1989-11)
      Verifying the quality of a PCM (or PAM) telemetry system is an important concern before any launch. A frame simulator generated test is definitely inchoate to exercise the link’s real world disturbances response behavior. It should be completed with tests involving some disturbances measurements.

      Meyer, Steven; Naval Weapons Center, China Lake, CA (International Foundation for Telemetering, 1989-11)
      During high-power microwave (HPM) testing, where the item under test is subjected to power levels up to several thousand W/cm , the RF energy present will make typical 2 telemetry RF links useless. Therefore, other means must be used to retrieve the data during the tests. One method to accomplish data retrieval is to replace the RF data link with a fiber-optic link. This is done by replacing the transmitter with a fiber-optic transmitter on the sending end and the RF receiver with a fiber-optic receiver on the receiving end. Although this sounds simple, it is not always so. Solutions for PCM and FM-FM systems are relatively straightforward, whereas PAM systems present a unique set of problems. This paper addresses possible solutions for PCM and FM-FM and three possible solutions for PAM, one being by using a PAM-to-PCM converter.
    • Simulator for Checkout of Telemetry Receiving Systems

      DeWaters, Ronald W.; Naval Surface Warfare Center (International Foundation for Telemetering, 1989-11)
      Reception of missile telemetry data on board Navy ships is accomplished by using portable telemetry receiving systems which must be assembled/ disassembled for every missile firing exercise. In some cases, system setup problems have resulted in the loss of telemetry data when the missile is fired. The telemetry test simulator was developed by the Naval Surface Warfare Center (NSWC) to generate a telemetry stream identical to that of the missile telemeter. This simulated stream allows for an end to end checkout of the receiving system prior to missile launch which greatly reduces the chance of lost telemetry data upon actual missile firing.

      Lynch, Thomas J., III; Fortmann, Thomas E.; Briscoe, Howard; Fidell, Sanford; BBN Systems and Technologies Corporation (International Foundation for Telemetering, 1989-11)
      Multiprocessing computer systems offer several attractive advantages for telemetry-related data acquisition and processing applications. These include: (1) high-bandwidth, fail-soft operation with convenient, low-cost, growth paths, (2) cost-effective integration and clustering of data acquisition, decommutation, monitoring, archiving, analysis, and display processing, and (3) support for modern telemetry system architectures that allow concurrent network access to test data (for both real-time and post-test analyses) by multiple analysts. This paper asserts that today’s general-purpose hardware and software offer viable platforms for these applications. One such system, currently under development, closely couples VME data buses and other off-the-shelf components, parallel processing computers, and commercial data analysis packages to acquire, process, display, and analyze telemetry and other data from a major weapon system. This approach blurs the formerly clear architectural distinction in telemetry data processing systems between special-purpose, front-end, preprocessing hardware and generalpurpose, back-end, host computers used for further processing and display.

      Johnson, Brian; Science Applications International Corporation (International Foundation for Telemetering, 1989-11)
      T&E range instrumentation systems of diverse designs are located throughout the United States. Used for testing of aircraft weapons systems and missiles these systems are large, expensive, and unique to each site. New technologies now emerging are making possible the construction of small, inexpensive range instrumentation systems of common design and significant capability. Using industry-standard bus designs and distributed general-purpose microprocessors, these systems, while still using existing instrumentation, will be able to provide growth flexibility that is not inherent in today’s monolithic architectures. This paper will review the design and capabilities of a few systems currently under construction as well as describe what can be expected in the immediate future of range instrumentation systems with the transponders using multilateration techniques for position location and message handling. Range instrumentation (RI) systems of various forms have been in place since the testing of weapons systems began. As the technology evolved computers became integral parts of these systems, significantly expanding their capabilities both from the standpoint of data capture and data analysis. That this evolution is continuing can be demonstrated by two RI systems currently under construction: A fixed-site tracking system and mobile tracking system (the Mobile Sea Range, MSR). While these new systems define the state-ofthe-art in computer-based RI systems, new technologies now evolving and the budget-conscious climate that is likely to continue for many years will require changes in our thinking of what an RI system should look like and how it will be maintained. What follows is a brief description of both these fixed and mobile RI systems, an analysis of RI trends, and a few recommendations of what can be done to improve future systems.

      Smith, Dennis L.; Veda Systems (International Foundation for Telemetering, 1989-11)
      Flight test engineers, a unique group of individuals whose tasks are to test and evaluate aircraft in operational environments, are faced with the problem of supporting the complex instrumentation formats and higher data rates that are now appearing on airborne instrumentation platforms. The majority of off-the-shelf portable telemetry support equipment has not kept up with the demands of the modern-day Flight Test Engineer-Data Analyst.

      Boulinguez, Marc; Applications Engineer, Space Systems (International Foundation for Telemetering, 1989-11)
      This paper presents a new family of telemetry and command front-end products, as applied to spacecraft ground segment systems. The general philosophy behind both check-out systems and command and control stations has recently evolved from large host computers to a more distributed architecture, where more processing for either recovering telemetry data or encoding commands is done at the front-end level. The overall reliability and safety of such systems have also called for communications oriented subsystems, complying with international standards (ETHERNET, IEEE 488, CCITT X25...). For the same reasons, satellite manufacturers and operators are now requesting more integrated front-end subsystems, which include in one unit subcarrier modulation (PSK or FSK) and baseband functions (Telemetry synchronisation or command encoding), as well as the corresponding built-in test capabilities. The 3000 series family of products complies with all the criteria enumerated above. Furthermore, it offers a line of matching telemetry and command units, available in both overall check-out (O.C.O.E.) and Telemetry, Tracking and Command (T.T.&C.) versions, thus facilitating the complete integration of a spacecraft system from ground test to in-orbit operation. The choice of industry standards such as the VME bus, the hostbased development of firmware in “C”, also ensure product modularity, allowing easy expansion or adjustments to the specific requirements of particular missions or programs. The 3000 series complies with the European Space Agency (E.S.A.) PSS-45 and PSS-46 standards, which are compatible with NASA/GSFC Aerospace Data Systems Standards and the NASCOM message format. These concepts are illustrated in the application of the 3000 series products in the EUTELSAT II program. Architectures for both the ground check-out systems and the control stations are presented; technical choices for system set-up and control and communications in-between subsystems are discussed. Future trends and new standards in spacecraft telemetry, command and control systems are presented, and particularly the implementation in the 3000 series products of the recommendations from the Consultative Commitee on Space Data Systems (C.C.S.D.S) on “Packet” Telemetry and Telecommand, as well as channel coding (Viterbi and ReedSolomon algo- rythms) using proprietary developments of VLSI circuits.

      Rauch, William D.; Realtime Data Systems Center (International Foundation for Telemetering, 1989-11)
      The next 25 years will bring about a revolution in telemetry acquisition and processing. Airborne systems will become smaller and faster, providing additional monitoring and processing capabilities to test vehicles. In addition, ultra-high speed on-board data networks will provide communications between data collection and processing units. The telemetry platforms of tomorrow will be required to collect the entire contents of the data network, in a manner similar to today’s MIL-STD 1553 technology. The ground station of tomorrow will be required to process this bus information and provide it to the users for analysis. Ground station components, including intelligent front-ends and host processors could easily be replaced by a combination of on-board communication network processors (similar to the current 1553 processors) linked to a ground system data network. Processing could be shifted to the vehicle while ground functions remain dedicated to recording and analysis. Specialized workstations will provide for user analysis, history recording, and display. Ground networks will use shared (reflected) memory concepts to provide for addition of unlimited workstations separated by much greater distances than are associated with today’s shared memory systems.

      Svensson, Ake; Maoz, Michael; Saab Missiles AB; RAFAEL; Aydin Vector Division (International Foundation for Telemetering, 1989-11)
      Aydin Vector Division has developed and manufactured an airborne, high shock, wideband FM/FM telemetry system for Saab Missiles AB in Sweden. This system was presented in the ITC Proceedings of 1988, Volume XXIV, pp 71-84 (Ref [1]). Three such systems were supplied. Saab Missiles AB also awarded Aydin Vector Division with an additional order for a larger number of high shock, computer based, specially designed, miniature PCM/FM airborne telemetry systems. These systems were developed, manufactured and supplied to Saab Missiles AB, and have been extensively and successfully used in the Swedish program. The PCM/FM telemetry package described in this paper was used for the system testing and the firing trials program of a mortar projectile, where the measurement requirements included micro processor interfaces, as well as a high amount of analog and bi-level data channels. The paper covers the specifications of the PCM/FM system mentioned above, the concept that was used to meet these specifications, the system’s mechanical and electrical design, the packaging technique and some of the test results.