• The Evolution of a Telemetry Groundstation Utilizing Today's Open Standards

      Friedman, Paul; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      Computer industry and government standards have had a profound effect on modern telemetry ground stations. Installations are no longer one-of-a-kind inflexible systems built to the specifications of a single user - meeting their needs without regard to the rest of the community. This paper will examine the effect that the evolution of significant graphics, network, operating system, and architecture standards has had on commercial telemetry ground station system products. It will also explore the issue of "open" versus proprietary architectures. The paper closes with a description of a system designed from its very inception to meet and grow with standards.
    • Design Equations for a Specified Bit Error Rate for PCM/FM+FM/FM and Optimum Bandwidths

      Carden, Frank F.; New Mexico State University (International Foundation for Telemetering, 1994-10)
      A PCM/FM+FM/FM system combines the bit sequence with the modulated subcarriers at baseband and the resultant modulates the carrier. This paper concerns the design of this composite system. Such a system combines the spectral efficiency of the analog system with the accuracy of a PCM system when needed for specific sensors and allows the direct transmission of binary computer words if necessary. The impact of the subcarriers on the bit error rate of the bit sequence is determined. Equations are given which allow the degradation of the FM/FM channels by the bit sequence to be determined. Further, it is shown in this work that as the IF bandwidth is increased above twice the bit rate, the peak deviation of the carrier by the bit sequence is no longer .35 times the bit rate. An optimum value for IF bandwidths is determined. The developed design equations allow the design of the composite system with a specified bit error rate and a specified signal to noise ratio in the subcarrier channels.
    • Binary PCM/FM Tradeoffs Between Spectral Occupancy and Bit Error Probability

      Law, Eugene L.; NAWCWPNS (International Foundation for Telemetering, 1994-10)
      The bit rates of telemetry systems are increasing rapidly. Higher bit rates occupy more spectra and result in decreased link margin. The major signal parameters that affect the spectral occupancy and bit error probability (BEP) of binary pulse code modulation (PCM)/frequency modulation (FM) signals are the bit rate, code, premodulation filter, and peak deviation. The measured spectral occupancy is also affected by the spectrum analyzer (or other measurement equipment) settings. Additional parameters that affect the BEP include the receiver intermediate frequency (IF) filter, the FM demodulator, and the bit detector. This paper will present the effects of these parameters on the measured 99% and -60 dBc bandwidths and the BEP of binary PCM/FM telemetry signals. Normalized BEP and bandwidth curves will be presented.
    • 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.

      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. This places an increased demand on the remote capabilities of the equipment used in the telemetry system. Furthermore, emphasis has been placed on the ability to decrease the space and power consumption of the telemetry system to facilitate transportability of the a single telemetry system to multiple sites. Finally, today's telemetry systems demand that all equipment provide multiple functions to provide the maximum performance for the lowest system cost.

      Kleen, Mitchell; White, Joey; Policella, Joseph; CAE-Link Corporation (International Foundation for Telemetering, 1994-10)
      The Space Station Verification and Training Facility is using an object-oriented design methodology for software design, a rate monotonic scheduling and message passing system to support the highly distributed environment, and the Ada language to implement most of the software. One of the subsystems within the Space Station and Training Facility is the Space Network Simulator. Space Network simulators are used to provide training of ground controllers and flight crews, providing a model of real-world formats and protocols. This gives the controller the appearance of a real-world network, providing valuable training. To develop a simulation of the space network within this distributed environment, software objects are under development to dynamically simulate the existence of the space vehicle(s) and their communication components. Communication components include the on-board antennas, transponders, communication systems, and corresponding communication ground control facilities. Telemetry systems are used in the simulation to provide the control of actual data manipulation, as a function of the state of the simulated Space Network. The telemetry system automatically formats appropriate telemetry characteristics through mode and control commands. A software model is under development to provide a transparent interface between the software objects and the telemetry system, allowing the objects to execute without knowledge of the particular telemetry system in use. A transparent interface between the software and hardware, within this object-oriented methodology, reduces the propagation of change to software models as the interface requirements change.
    • A New Error Control Scheme for Remote Control System

      Zhou, Tingxian; Yin, Xiaohua; Zhao, Xianming; Harbin Institute of Technology (International Foundation for Telemetering, 1994-10)
      How to rise the reliability of the data transmission is one of the main problem faced by modern digital communication designers. This paper studies the error-correcting codes being suitable for the channel existing both the random and burst error. A new error control scheme is given. The scheme is a concatenated coding system using an interleaved Reed-Solomon code with symbols over GF (24) as the outer code and a Viterbi-decoded convolutional code as the inner code. As a result of the computer simulation, it is proved that the concatenated coding system has a output at a very low bit error rate (BER)and can correct a lot of compound error patterns. It is suitable for the serious disturb channel existing both the random and burst error. This scheme will be adopted for a remote control system.
    • 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.
    • Control of a Remote Receiving Station and Data Processing at RA Range Hebrides

      Mackenzie, Donald; Fielding, Richard; Serco, RA Range Hebrides; Loral Test & Information Systems (International Foundation for Telemetering, 1994-10)
      The Royal Artillery Range (RA Range) is the British Army's weapons practice range in the Outer Hebrides of Scotland. The large sea range is also used by the Royal Air Force and Royal Navy for new weapons system evaluation and in service practice firing. This paper describes the telemetry facility comprising of two prime sites separated by 40 miles of open sea. Tracking antennas and receivers are at the remote island site of St Kilda with data processing and control at the Range Control Base (RCB), Benbecula. To improve operational capabilities and effectiveness, full remote control and monitoring of the multiple receivers and combiners has been installed. Radar tracking outputs are processed in the telemetry computer to produce individual antenna pointing demands.

      Porter, Jim; Meyers, Tom; SEMCO (International Foundation for Telemetering, 1994-10)
      Embedded "Card-Based" receivers are one of the latest innovations in telemetry reception. These products provide substantial power and flexibility in a small form factor (one slot, PC or VME). In many applications they are a cost effective alternative to conventional telemetry receivers. This paper analyzes currently available products with regard to their features, capabilities, and performance, as well as highlighting typical applications.

      Lam, Daniel-Hung; Moyes, Robert; SEMCO; BME (International Foundation for Telemetering, 1994-10)
      This paper discusses the design and performance of the FM/PM/BPSK "personal computer card-based" receiver. In PSK, a carrier recovery technique must be used for signal demodulation. Costas loop is a well known method and is the basis in the design of the BPSK demodulation. A new design approach employing digital Box Car arm filters is used to improve receiver performance and flexibility. Detail design and performance of the digital Costas loop will be explored in a later section. A classical technique is employed for Phase demodulation with the use of tracking Phase Lock Loop. Frequency demodulation is designed around a simple, single FM discriminator IC.

      Chavez, Tom; White Sands Missile Range (International Foundation for Telemetering, 1994-10)
      Testing into the 21st Century will entail significantly different techniques than those presently used. Processing of data sources such as telemetry, radar, optics, and others will change from a merging of data for post flight reduction, to a real time fusion of data for mission support. Change in the philosophy of what is telemetry data will drive the entire processing and display systems used for real time support. Telemetry will move further from being used primarily for airframe performance reporting, to being a source of precision TSPI, video, and endgame performance. This paper will touch on these aspects and explore the processes such as techniques, displays, and standards that will evolve to meet these requirements.

      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.

      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.

      Hines, Dennis O.; Rhea, Donald C.; Williams, Guy W.; Edwards Air Force Base; SPARTA Inc. (International Foundation for Telemetering, 1994-10)
      The rapid technology growth in the aerospace industry continues to manifest itself in increasingly complex computer systems and weapons systems platforms. To meet the data processing challenges associated with these new weapons systems, the Air Force Flight Test Center (AFFTC) is developing the next generation of data acquisition and processing systems under the Advanced Data Acquisition and Processing Systems (ADAPS) Program. The ADAPS program has evolved into an approach that utilizes Commercial-Off-The-Shelf (COTS) components as the foundation for Air Force enhancements to meet specific customer requirements. The ADAPS program has transitioned from concept exploration to engineering and manufacturing development (EMD). This includes the completion of a detailed requirements analysis and a overall system design. This paper will discuss the current status of the ADAPS program including the requirements analysis process, details of the system design, and the result of current COTS acquisitions.
    • 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.

      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.

      Morimoto, Todd A.; Nowitzky, Thomas E.; Grippando, Steven A.; Space & Missile Systems Center; Loral Space & Range Systems (International Foundation for Telemetering, 1994-10)
      An increasing number of satellite users and manufacturers are looking to lightweight, inexpensive satellites as substitutes to traditional large, expensive satellites with multiple payloads. Neither the Department of Defense nor the commercial sector can bear the financial or reputational consequences associated with massive program failures. With the low cost and weight of these new satellites, users can achieve mission success without great risk. One example of this new class of inexpensive spacecraft is the RADCAL (RADar CALibration) satellite. Detachment 2, Space & Missile Systems Center at Sunnyvale, CA operates the satellite. RADCAL is a 200-pound polar orbiting satellite with an average altitude of 450 miles. It is primarily used by 77 worldwide radars to calibrate their systems to within five meter accuracy. Also flying on board RADCAL is a communication payload for remote field users with small radios. The RADCAL program has satisfied all mission requirements. However, with the limited size and cost come certain challenges, both in the satellite and on the ground. Pre-launch testing was not as comprehensive as with more expensive programs; anomalies have arisen that require extensive workarounds. Data management is not a straightforward task, and it is sometimes difficult and inexact to track satellite performance. These challenges are presented with their solutions in the following discussion; this paper addresses the functional, operational, and testing aspects associated with the RADCAL satellite.
    • 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.