• Planned Evolution of Range Telemetry and Communications into the Public Data Network

      Erdahl, Mike; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The area of range telemetry and communications has been under budget constraints and interoperability enhancement requirements for some time. The near-term onslaught of multimedia communications offerings by telephony and communications companies is certain to cause range engineering personnel to conduct extensive research and possibly make numerous decisions on procurements and technologies before standards are finalized. This paper will address a low-risk migration path for range telemetry to the new multimedia communications for ranges based on current capabilities. This migration path has an end goal of positioning the ranges to take advantage of future multimedia communications as they become available, while leveraging off of current products and procurements, without a major investment.
    • Portable Airborne Digital Data System Recorder

      Harris, Kevin E.; Veda Incorporated (International Foundation for Telemetering, 1994-10)
      Veda Incorporated has developed an airborne instrumentation recorder for a major commercial aircraft manufacturer. The recorder was developed for use in the aircraft company's Portable Airborne Digital Data System (PADDS), a small scale data acquisition and monitor system used for flight testing. The recorder is designed around an off-the-shelf 8mm tape drive, the Exabyte 8505. It records asynchronous, variable-rate data in a proprietary 24-bit recording format, and allows the data to be played back in real time. Its RS-422 control interface is designed to imitate the recorder used in the company's large scale data acquisition system, the Ampex DCRSi-II. Special provisions allow it to withstand the environment of an airplane's EE bay.

      Reinsmith, Lee V.; TYBRIN Corporation (International Foundation for Telemetering, 1994-10)
      This paper describes the application software used in the Message Processing System at the Air Force Development Test Center (AFDTC), Eglin AFB. The focus is on the Alpha AXP application software designed and developed to log, process, and reformat IRIG Chapter 8 1553 data. The main data reduction and editing capabilities of the processing phase are explained: message output selection, message output sampling, message translation, error identification, and IRIG Chapter 8 time editing. The design of and methods used to produce the output files, the BBNProbe STD file, and the 1553 message summary report are described. This software’s flexibility and comprehensiveness in processing, reducing, and re-formatting 1553 message data will enable AFDTC to satisfy current and future post-mission processing requirements.
    • Probability of Bit Error on a Standard IRIG Telemetry Channel Using the Aeronautical Fading Channel Model

      Nelson, N. Thomas; Brigham Young University (International Foundation for Telemetering, 1994-10)
      This paper analyzes the probability of bit error for PCM-FM over a standard IRIG channel subject to multipath interference modeled by the aeronautical fading channel. The aeronautical channel model assumes a mobile transmitter and a stationary receiver and specifies the correlation of the fading component. This model describes fading which is typical of that encountered at military test ranges. An expression for the bit error rate on the fading channel with a delay line demodulator is derived and compared with the error rate for the Gaussian channel. The increase in bit error rate over that of the Gaussian channel is determined along with the power penalty caused by the fading. In addition, the effects of several channel parameters on the probability of bit error are determined.
    • Processing Real-Time Telemetry with Multiple Embedded Processors

      BenDor, Jonathan; Baker, J. D.; Dovetail Systems Corporation; SEMCO (International Foundation for Telemetering, 1994-10)
      This paper describes a system in which multiple embedded processors are used for real-time processing of telemetry streams from satellites and radars. Embedded EPC-5 modules are plugged into VME slots in a Loral System 550. Telemetry streams are acquired and decommutated by the System 550, and selected parameters are packetized and appended to a mailbox which resides in VME memory. A Windows-based program continuously fetches packets from the mailbox, processes the data, writes to log files, displays processing results on screen, and sends messages via a modem connected to a serial port.
    • RadarMap: A Multi-Platformed Range Display Utility

      Rivero, Juan J.; Rarick, Michael J. (International Foundation for Telemetering, 1994-10)
      RadarMap is designed to take PCM-encoded radar data and process it to display the trace of radar targets on a map of the Eglin Test Range. Written in C, X Window, and OSF/Motif, RadarMap runs on a DECStation 5000/240 and utilizes the Loral Data Gathers C functions library to directly access PCM parameters from a Loral System 500 telemetry rack. X Window (a hardware-independent bitmapped graphics display system), OSF/Motif, and the Data Gathers libraries allow portability to other operating systems that support a C compiler and these libraries.

      O'Brien, R. Michael; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      With today's telemetry systems, an hour-long analog test tape can be digitized in one hour or less. However, the digitized data produced by today's telemetry systems is usually not in a format that can be directly analyzed by the test engineer's analysis tools. The digitized data must be formatted before analysis can begin. The data formatting process can take from one to eight hours depending on the amount of data, the power of the system's host computer, and the complexity of the analysis software's data format. If more than one analysis package is used by the test engineer, the data has to be formatted separately for each package. Using today's high-speed RISC processors and large memory technology, a real-time Flexible Data Formatter can be added to the Telemetry Front End to perform this formatting function. The Flexible Data Formatter (FDF) allows the telemetry user to program the front-end hardware to output the telemetry test data in a format compatible with the user's analysis software. The FDF can also output multiple data files, each in a different format for supporting multiple analysis packages. This eliminates the file formatting step, thus reducing the time to process the data from each test by a factor of two to nine.
    • A Real-Time Telemetry Data Processing System with Open System Architecture

      Jun, Zhang; MeiPing, Feng; Yanbo, Zhu; Bin, He; Qishan, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 1994-10)
      In face of the characteristics of multiple data streams, high bit rate, variable data formats, complicated frame structure and changeable application environment, the programmable PCM telemetry system needs a new data processing system with advanced telemetry system architecture. This paper fully considers the characteristics of real-time telemetry data processing, analyzes the design of open system architecture for real-time telemetry data processing system(TDPS), presents an open system architecture scheme and design of real-time TDPS, gives the structure model of distributed network system, and develops the interface between network database and telemetry database, as well as telemetry processing software with man-machine interface. Finally, a practical and multi-functional real-time TDPS with open system architecture has been built, which based on UNIX operating system, supporting TCP/IP protocol and using Oracle relational database management system. This scheme and design have already proved to be efficient for real-time processing, high speed, mass storage and multi-user operation.
    • Recovery of Telemetered Data by Vertical Merging Algorithms

      Hoag, Joseph E.; Kalibjian, Jeffrey R.; Shih, Dwight; Toy, Edward J.; Lawrence Livermore National Laboratory; EL and Associates, Inc. (International Foundation for Telemetering, 1994-10)
      A long standing problem in telemetry applications is the recovery of data which has been damaged during downlink. Data recovery can be significantly improved by telemetering information in a packet format which employs redundant mechanisms for data encapsulation. A simple statistical algorithm (known as a "merge" algorithm) can be run on the captured data to derive a "least damaged" data set.

      Humpherys, Brian; Brigham Young University (International Foundation for Telemetering, 1994-10)
      This paper describes a method for determining high resolution time, space, and position information for a test range flight vehicle using four tracking receivers. Equipped with GPS time systems, each receiver records the exact time at which a time marker embedded in the transmitted TM data stream is received. With this information, the time difference of arrival for the time markers at three of the receivers can be calculated referenced to the fourth. Using this time difference, the position of the transmitter can be determined. The accuracy with which the received signal time delay can be calculated depends on the accuracy of the GPS time system at each receiver. The effect of time accuracy on positional resolution is evaluated.

      Jin, Minglu; Zhang, Qishan; Shenyang Institute of Aeronautical Engineering; Beijing University of Aero. & Astr. (International Foundation for Telemetering, 1994-10)
      In this paper, by using computer simulations, the interference of channel data in the SDM telemetry system is investigated, the performance of the copy demultiplexing is examined, and finally the selection rule of Walsh functions is recommended.

      Horan, Stephen; Minnix, Timothy; New Mexico State University (International Foundation for Telemetering, 1994-10)
      Small satellites have been perceived as having limited access to NASA's Space Network consisting of the TDR satellites and associated ground terminals. This paper presents the potential for access of the space network using basic small satellite design constraints and a simple helical antenna for the communications links. From the analysis derived through simulation of the orbit of both satellites, small satellites can be shown to have up to 30 minutes per orbit of single-TDRS access. Data rates on the order of 100 kbps are possible in this configuration with total daily data volumes in excess of 100 Mbits being achievable. Design parameters are given for a variety of orbital inclination angles and spacecraft transmission powers to illustrate the expected available contact time for such small satellites to the Space Network. This is compared with typical access time through a fixed ground station.
    • A Software Architecture for Client-Server Telemetry Data Analysis

      Brockett, Douglas M.; Aramaki, Nancy J.; BBN Systems & Technologies (International Foundation for Telemetering, 1994-10)
      An increasing need among telemetry data analysts for new mechanisms for efficient access to high-speed data in distributed environments has led BBN to develop a new architecture for data analysis. The data sets of concern can be from either real-time or post-test sources. This architecture consists of an expandable suite of tools based upon a data distribution software "backbone" which allows the interchange of high volume data streams among server processes and client workstations. One benefit of this architecture is that it allows one to assemble software systems from a set of off-the-shelf, interoperable software modules. This modularity and interoperability allows these systems to be configurable and customizable, while requiring little applications programming by the system integrator.
    • Space Tracking Systems/ Options Study

      Grelck, John; Ehrsam, Eldon; Means, James A. (International Foundation for Telemetering, 1994-10)
      This paper presents the findings of the Space Tracking Systems/Options Study (STS/OS) and indicates its impact on the telemetering community. The STS/OS was commissioned by Air Force Test & Evaluation (AF/TE) to develop a long range plan (vision and roadmap) for the AF Test & Evaluation (T&E) community to ensure affordable capabilities (telemetry, tracking and commanding) for the future (2003-2008). The study was conducted by the Air Force Materiel Command (AFMC), Space & Missile Systems Center (SMC), Detachment 9, at Vandenberg AFB (VAFB), with support from the primary AFMC T&E centers, the Air Force Operational Test & Evaluation Command (AFOTEC), and the Air Force Space Command (AFSPC). Both "open air" aeronautical and astronautical test needs were considered. The study solicited requirements for existing and future programs, extrapolated existing and planned test capabilities out into the future, then compared the two to identify future shortfalls in capabilities and specific actions that are necessary to insure that the future program needs can be met. Three critical types of testing were identified that cannot be satisfied with existing or planned instrumentation. These are: large area testing (LAT), over the horizon testing (OTH), and space weapons testing (SWT). A major deficiency was also uncovered in end game scoring for air and space intercepts, where inadequate capability exists to perform the required vector miss-distance measurement. This paper is important to the telemetering community because it identifies the Global Positioning System (GPS) as the primary time space position information (TSPI) system for all future open air testing. GPS provides a passive capability that permits each vehicle to determine its own precise TSPI. Means must be provided, however, for the vehicle to relay its position to the appropriate range control center. The paper shows that the problems with down linking telemetry, aircraft buss data, digital audio, digital video, and TSPI collectively represent the need for a very capable datalink. Likewise, the need to uplink commands, synthetic targets, synthetic backgrounds, and target control information also represents the need for a very capable datalink. With its extensive expertise in RF linkages, the telemetering community is ideally suited to address this need for a robust datalink for the future of T&E.
    • Sub-Optimum Receiver Filters

      Osborne, William P.; Gutierrez, Alberto; New Mexico State University (International Foundation for Telemetering, 1994-10)
      This paper presents a method for analyzing the performance of a digital receiver when using standard analog filters in place of the ideal matched filter. Expressions are developed for the probability of error and performance loss of the sub-optimum receiver as functions of the minimum eye value and noise bandwidth of the suboptimum receiver filter. A method is developed for choosing the best sub-optimum filter in the sense of minimizing the probability of error. The best sub-optimum Bessel filter of order less than or equal to 6 is specified in terms of 3-dB bandwidth and filter order for a system with a rectangular transmit pulse. This method is applicable to other transmit pulse shapes and can be applied to channels with limited bandwidth. The optimum 3-dB bandwidth obtained here can be scaled relative to the symbol rate to correspond to any practical system.

      Cardinal, Robert; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The success of the client/server paradigm for modern networked telemetry systems continues to stress the LAN that carries data generated from the acquisition front ends to the display workstations and the file servers on the LAN. As the number of LAN-attached devices such as Loral's System 500 Model 550 (Loral 550) telemetry front end, workstations, and file servers grows beyond two, the Ethernet LAN collision rates increase and the throughput slows down. At what point the network performance declines is a function of the specific application bandwidth demands required. This paper describes a new method for boosting LAN performance by providing Ethernet switching and protocol filtering. The performance of the LAN is critical to the performance of the complete telemetry enterprise architecture.

      Toole, Michael T. (International Foundation for Telemetering, 1994-10)
      Since the Gulf War, there has been significant interest in Theater Missile Defense (TMD) resulting in funding growth from tens of millions of dollars at the time of the Gulf War to $1.7 Billion in 1994. The Ballistic Missile Defense Organization (BMDO) has developed a Theater Missile Defense test and evaluation program that will assess technological feasibility and the degree to which system functionality and performance meet technical and operational requirements. The complexity of the TMD program necessitates a comprehensive test program which includes flight testing, ground testing, and modeling and simulation. This article will provide and overview the requirements and capabilities needed to satisfy these requirements. The data processing, and telemetry communities will play a major role in providing the expertise to support the development of the nation’s future Theater Missile Defense capabilities.

      O'Cull, Douglas C.; Microdyne Corporation (International Foundation for Telemetering, 1994-10)
      With the increased concerns for reducing cost and improving reliability in today's telemetry systems, many users are employing simulation and automation to guarantee reliable telemetry systems operation. Pre-Mission simulation of the telemetry system will reduce the cost associated with a loss of mission data. In order to guarantee the integrity of the receive system, the user must be able to simulate several conditions of the transmitted signal. These include Doppler shift and dynamic fade simulation. Additionally, the simulator should be capable of transmitting industry standard PCM data streams to allow pre-mission bit error rate testing of the receive system. Furthermore, the simulator should provide sufficient output power to allow use as a boresite transmitter to check all aspects of the receive link. Finally, the simulator must be able to operate at several frequency bands and modulation modes to keep cost to a minimum.
    • A Telemetry System with Fibre Transmission

      Qishan, Zhang; Xianliang, LI; Jun, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 1994-10)
      It is known that a PCM telemetry system features with good accuracy, great dynamic range, and low noise. And when more than fourteen data channels are required, the PCM is generally the best choice. The paper describes the general ideas involved in developing a PCM telemetry system with fibre transmission.
    • TWARSES The Two Wire Automatic Remote Sensing and Evaluation System

      Dahl, Ernest A.; Naval Surface Warfare Center (International Foundation for Telemetering, 1994-10)
      The Two Wire Automatic Remote Sensing and Evaluation System (TWARSES) automatically transmits and evaluates information (data) from remote sensors on a common two wire buss. In addition the system presents automatic evaluation and alarms, which provide both location data and sensor readout data of the monitored area. This system is a stand-alone modular system in which a common two wire line installed bow-to-stern and top-to-bottom, connects, integrates, evaluates, and powers a multiplicity of sensors. The United States Navy uses this system to provide safety and survivability by monitoring environmental gases, liquid levels, and power, temperature, and humidity levels on ships and in office buildings. The automatic monitoring system operates in a manner similar to an automatic, multiscriber, party-line telephone system. The system is controlled by the Scanner/Display unit which interrogates each of the 150 possible sensors according to the program stored in a microprocessor. This patented system provides a separate address for each sensor transponder, permitting all of the transponders to be simply connected in parallel across a common, twisted pair transmission line. The interrogating signal is also used to provide power (6V - 2mA) for the sensor transponders and their associated sensors. This further simplifies the system by eliminating the need for a separate source of power at each sensor location. Each sensor is interrogated with a 15-bit sequence which specifies: (1) the address of the sensor which is to reply, (2) the parameter to be reported (e.g. voltage, temperature, humidity, etc.) And (3) the desired precision (which sets the length of the reply). The interrogation is transmitted as frequency shift-keyed signal. Among the various types of interrogation signals which could be used (AM, FM, etc.) frequency shift-keying (FSK) was selected because: