• LINUX POWERED TELEMETRY PROCESSING

      Ayala, Joseph; Sorton, Eric; Command & Control Technologies Corp. (International Foundation for Telemetering, 2000-10)
      Since its debut, the Linux operating system has garnered much attention in the software development community. This paper discusses the open source operating system, Linux, and it’s application as the operating system powering a commercial off-the-shelf telemetry processing system. The paper begins by discussing what are the real-time requirements of the operating system in a telemetry processing system. A discussion to the Linux system is then presented. Soft real-time features of Linux are discussed which allow it to meet the telemetry processing requirements. Linux is compared with the more traditional operating system products and points are made as to why open source software is just as capable, if not preferable, of handling mission critical applications. The paper also presents the authors’ view of future of Linux and open source software in the telemetry marketplace. The paper concludes with a summary of products available for Linux that support telemetry processing and the data acquisition environment.
    • TechSat21 TESTBED DATABASE

      Self, Lance; Kirtland Air Force Base (International Foundation for Telemetering, 2000-10)
      TechSat21 is sponsored by the Air Force Research Laboratory Space Vehicles Directorate and the Air Force Office of Scientific Research1. Its mission is to control a cluster of satellites that, when combined, create a “virtual satellite” with which to conduct various experiments in sparse aperture sensing and formation flying. Customers of the TechSat21 database include mission planners and system engineers. Mission Planners need information that allows them to make high level planning and scheduling decisions. System Engineers need information to predict satellite sub-system problems and conduct satellite design and performance trade studies. This paper describes those users and the project database.
    • PARAMETRIC ESTIMATION OF THE SCATTERING FUNCTION FOR ARTM CHANNEL SOUNDING DATA

      Rice, Michael; Landon, David; Brigham Young University (International Foundation for Telemetering, 2000-10)
      Parameterized data from ARTM channel sounding test flights are used to derive a parameter-based estimate of the scattering function. The Doppler bandwidth and Doppler spread, important measures of channel dynamics, can be estimated from such a scattering function. Data collected from ARTM Flight 11 suggest that the Doppler bandwidth is larger than 6.7 Hz. Even for very small collections of parameterized data, surprising agreement is shown to non-parametric scattering function estimates. This confirms modeling assumptions and offers a way to achieve significant reductions of storage requirements.
    • ON THROUGHPUT ANALYSIS OF THE MARS IN-SITU ARQ PROTOCOL

      Liang, Robert; Kwan, Bruce; Florens, Cedric; Jet Propulsion Laboratory (International Foundation for Telemetering, 2000-10)
      Combating harsh and unpredictable channel environments is a part of the design of any in-situ communication system (i.e. rover to lander, rover to orbiter, etc.). Channel characteristics can range from simple additive white Gaussian noise (AWGN) channels to more bursty fading channels found in rover to orbiter links (i.e. canyon scenarios and typical orbiter passes around mountain ranges). A combination of forward error correction and automatic repeat request (ARQ) schemes are commonly used to provide a more robust communications link. ARQ enhances the communication link particularly for bursty fading channels. Go-Back-N is a commonly used ARQ scheme and is an option in the newly developed Consultative Committee for Space Data Systems (CCSDS) Proximity-1 Link protocol [7], a data link layer protocol targeted specifically for in-situ applications. Optimization of frame sizes and retransmission persistence of the ARQ scheme require a good analytical model of how the scheme performs over various channel conditions. In this paper, an analytical framework for modeling the COP-1 protocol is presented for both AWGN channels along with bursty fading channels. A Gilbert-Elliot two-state Markov model is used to model a bursty fading channel.
    • A MODULAR APPROACH TO LANDSAT 7 GROUND PROCESSING

      Mah, G. R.; Pater, R.; Alberts, K.; O’Brien, M.; Senden, T.; Raytheon (International Foundation for Telemetering, 2000-10)
      Current Landsat 7 processing is based on a single-string, multifunction approach. A follow-on system has been designed that repartitions functions across multiple hardware platforms to provide increased flexibility and support for additional missions. Downlink bit stream acquisition has been moved to lower cost systems functioning as “capture appliances” with high-speed network interconnections to Level 0 processing on generic compute servers. This decouples serial data stream acquisition from the processing system to allow the addition or replacement of compute servers, without the reintegration of specialized high-speed capture hardware. Moreover, it also allows the easy integration of new systems and missions without extensive system redesign or additional software.
    • ENHANCED PERFORMANCE OF FQPSK-B RECEIVER BASED ON TRELLIS-CODED VITERBI DEMODULATION

      Lee, Dennis; Simon, Marvin; Yan, Tsun-Yee; Jet Propulsion Laboratory (International Foundation for Telemetering, 2000-10)
      Commercial FQPSK-B receivers traditionally use symbol-by-symbol detection and have a 2 dB Eb=No loss relative to ideal QPSK at a bit error rate (BER) of 10^(-5). An enhanced FQPSK-B receiver using a Viterbi algorithm (VA) to perform trellis decoding is simulated and shown to have a 1.2 dB Eb=No improvement over symbol-by-symbol detection for 10^(-5)5 BER at the cost of increased complexity. A simplified Viterbi receiver with a reduced trellis and significantly less complexity is introduced with only a slight BER degradation compared to the full Viterbi receiver. In addition, a theoretical bit error probability expression for the symbol-by-symbol FQPSK-B receiver is derived and compared with simulation results.
    • FQPSK DEVELOPMENTS RECOMMENDED FOR CCSDS STANDARDIZATION BY NASA JPL

      Martin, Warren L.; California Institute of Technology (International Foundation for Telemetering, 2000-10)
      In 1992, international space agencies became concerned that increasing frequency band congestion, together with attempts by the mobile telephone industry to obtain additional bandwidth, would result in substantially more interference incidents. The CCSDS undertook a technical study to identify and recommend more bandwidth efficient modulation schemes, which would permit more users to co-exist in a frequency band while reducing interference incidents. This paper describes the contribution of the Jet Propulsion Laboratory (JPL) to that effort.
    • ULTRA HIGH BIT RATE (UP TO 1GBIT/S) BANDWIDTH EFFICIENT FQPSK ALL-DIGITAL MODULATOR/DEMODULATOR ARCHITECTURES AND NASA IMPLEMENTATIONS

      Ghuman, Parminder; Koubek, Steve; Winkert, Tom; Gray, Andrew; Lay, Norm; Yan, Tsun-Yee; National Aeronautics and Space Administration; California Institute of Technology (International Foundation for Telemetering, 2000-10)
      The paper presents ongoing efforts at NASA’s Goddard Space Flight Center and the Jet Propulsion Laboratory to develop ultra high bit rate bandwidth efficient FQPSK modulators and demodulators. The ability to transmit and receive ever-increasing amounts of extremely high rate data is an enduring challenge in the arena of near-earth space borne science missions. Reliable and efficient transmission of information at these data rates requires the use of power and bandwidth efficient modulations that exhibit low transmitter, receiver, and decoder complexity. Conventional high rate approaches for achieving spectral limiting typically employ sharp post amplifier filtering at the transmitter to limit the interference to the adjacent bands. However, using analog filtering alone can produce substantial intersymbol interference and other distortions that substantially affect the detection performance of the signal. In contrast, various theoretical classes of modulation waveforms can be tailored to provide varying degrees of bandwidth and power efficiency or robustness to non-linear transmitter distortions while incurring little or no performance losses. In order to realize many of these signal types, precise amplitude and phase control over the synthesis of these signals is required, typically necessitating the use of digital signal processing.
    • MODULATOR IMBALANCE EFFECTS ON THE FQPSK AIRBORNE TELEMETRY LINK

      Temple, Kip; Air Force Flight Test Center (International Foundation for Telemetering, 2000-10)
      When designing transmitters for quadrature modulation schemes, the designer always tries to achieve good balance and symmetry of the in-phase (I) and quadrature (Q) branches of the modulator in terms of amplitude, phase, and offsets. Perfect balance between modulators is ideal but rarely if ever achieved. The Advance Range Telemetry (ARTM) program has placed indirect specifications on the remnant carrier and sideband levels which are controlled by modulator imbalance. These specifications will govern the ARTM programs first generation of Feher’s patented quadrature phase shift keying, version B (FQPSK-B) [9] airborne telemetry transmitters. The ARTM Program has also adopted test procedures for quantifying these modulation imbalances. This paper looks at the effects of modulator imbalances on spectral occupancy and bit error probability of the airborne telemetry link. It also outlines how these imbalances influence the levels in one of the ARTM specifications. Recommendations are presented based on the measured data for higher bit rate telemetry systems.
    • COMPATIBILITY OF IRIG-106-00 STANDARDIZED FEHERPATENTED FQPSK WITH OTHER DATA LINKS AND WIDEBAND W-CDMA

      McCorduck, James A.; Feher, Kamilo; University of California, Davis; Entech Engineering; Digcom Inc. (International Foundation for Telemetering, 2000-10)
      The interoperability of Feher-patented Quadrature Phase Shift Keying (FQPSK) systems with future and legacy data links is discussed in this paper. In particular, the benefits of “forward” interoperability with 3G (3rd Generation) wireless systems such as WCDMA (Wideband Code Division Multiple Access) up to 40 Mchips/sec are highlighted. Other proposals of forward interoperability with future data links include an enhanced, ultra-bandwidth efficient FQPSK and 16-state FQAM (Feher’s Quadrature Amplitude Modulation) architectures. In addition, since FQPSK based systems have been proven in “dual use” systems and extensively tested and evaluated by the Department of Defense (DoD) and NASA, the analysis of “backward” interoperability with legacy data links such as GSM is also included in this paper.
    • HIGH PERFORMANCE SATELLITE RANGING TECHNIQUE UTILIZING A FLEXIBLE RANGING SIGNAL WAVEFORM

      McLean, Roger; Walker, Niles; Slivkoff, William; ITT Industries (International Foundation for Telemetering, 2000-10)
      Range to an orbiting satellite from a ground reference point (ground station) can be determined by measuring the round trip time for a waveform transmitted to the satellite and returned to the ground station (Turnaround Ranging) and more recently by using the Global Positioning System (GPS). This paper first summarizes and compares the two approaches. The paper then describes and analyzes a new turn-around ranging system which uses a flexible ranging waveform that provides spectral compatibility with existing Military, NASA, and Commercial satellite uplink/downlink signals.
    • STUDY ON HIGH-RATE TELEMETRY DATA REAL-TIME PROCESSING TECHNIQUES

      Chun, Yang; Hongling, Yang; Jie, Zhou; Xinan Electronic Engineering Institute (International Foundation for Telemetering, 2000-10)
      Owing to rapid development of PC industry, personal computer has been surprisingly improved on reliability and speed and it has been applied to many fields, such as aerospace, satellite and telemetry applications. As we all known, two aspects decide how fast the PC-based data acquisition can be reached. One aspect is CPU processing and the other is I/O bandwidth. Indeed, the first aspect has changed increasingly insignificant because the frequency of CPU has exceeded 700MHz which can satisfy fully the need of high rate data processing. So I/O bandwidth is the only key factor of the high rate PC-based data acquisition and we must adopt efficient data buffer techniques to satisfy the demand of telemetry data entry. This paper presents a buffered data channel which use memory mapping, EPLD and Dual-Port SRAM techniques. The operation platform of this design is WINDOWS95/98 and the software includes device driver and real-time processing routines.
    • THE APPLICATION OF MAP MATCHING METHOD IN GPS/INS INTEGRATED NAVIGATION SYSTEM

      Fei, Peng; Qishan, Zhang; Zhongkan, Liu; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 2000-10)
      Map matching method plays an important role in vehicle location and navigation systems. It employs the information in a digital map to compensate the positioning error. This paper presents a fuzzy-logic-based probabilistic map-matching algorithm used in GPS/INS integrated navigation systems, in which the reliability degree of map matching resolution is given explicitly as the decision basis in selecting matching road segment by utilizing the fuzzy comprehensive judgement. The results of experimental simulations have shown that the system performance gained significant enhancement by introducing this algorithm.
    • HOW TO USE RBDS TO TRANSMIT DGPS CORRECTION MESSAGE

      Shengxi, Ding; Qishan, Zhang; Junfeng, Li; Dayi, Zheng; Beijing University of Aeronautics and Astronautics; Chongqing Bashan Instrumental Factory (International Foundation for Telemetering, 2000-10)
      This paper introduces the frequency spectrum characteristic of FM radio broadcast and the message format of RBDS (Radio Broadcast Data System). DGPS correction message in RBDS is described in detail. A design method of RBDS/DGPS system is proposed and the RBDS/DGPS system developed by us is introduced. Finally, some special advantages of RBDS/DGPS system are given.
    • THE REALIZATION OF A NEW AVLNS BASED ON WINDOWS CE

      Wenzheng, Zhang; Xianliang, Li; Qishan, Zhang; Beijing University of Aeronautics and Astronautics (International Foundation for Telemetering, 2000-10)
      There is an increasing demand for practical and powerful navigation system to lead people from one place to another quickly and rightly. The introduction of a new embedded operating system, Windows CE, allows us to design a compact, low-cost, efficient autonomous vehicle location and navigation system. This paper discusses the advantages of Windows CE, demonstrates the possibility of building an AVLNS based on it. Then a realization scheme of hardware platform and navigation software is presented.
    • ADVANCED TELEMETRY PROCESSING AND DISPLAY SYSTEM (ATPDS)

      Leichner, Ted; Nicolo, Stephen J.; Snyder, Ed; Stacy, Mark; Ziegler, Charles; GDP Space Systems (International Foundation for Telemetering, 2000-10)
      This paper describes a PC-based Advanced Telemetry Processing and Display System (ATPDS)- a highend, real-time telemetry processing and display system implemented on a COTS PC platform. for A network-centric architecture was chosen from candidate architectures as the most viable for the ATPDS. The network-centric architecture is Windows NT-based, client/server based, supporting clients and servers on both local or remote PC workstations. The architecture supports distributing processing loads across multiple workstations, optimizing mission processing requirements. The advantage of this system is its flexibility and expandability with low acquisition and life-cycle support costs. The ATPDS allows the user to configure one or more small systems into a larger high-end system based on varying mission requirements.
    • THE STUDY ON SOFTWARE ADAPTIVE DETECTION TECHNOLOGY

      Changming, Li; Hao, Wu; Naitong, Zhang; Harbin Institute of Technology (International Foundation for Telemetering, 2000-10)
      Software radio is a new concept emerging in military communication and commercial wireless communication systems. Its kernel idea is to give a support with rapid building the flexible, modular, multiband and multimode wireless systems. This paper aims at programmable detection module in software radio application. It uses adaptive software to realize the detection function, this will greatly enhance the wireless receivers’ flexibility and intelligent process. From the simulation results of MPSK adaptive detection software, it can be concluded that adaptive software makes the system easy to realize detection function for various applications.
    • IMPROVING PERFORMANCE OF SINGLE OBJECT TRACKING RADAR WITH INTEGRATED GPS/INS

      Singh, Mahendra; McNamee, Stuart; Navarro, Rick; Fleishans, Amy; Garcia, Louie; Khosrowabadi, Allen; Waddan Systems; Air Force Flight Test Center; White Sands Missile Range; TYBRIN Corporation (International Foundation for Telemetering, 2000-10)
      A novel approach combines GPS receiver technology with micro-electromechanical inertial sensors to improve performance of single object tracking radar. The approach enhances range safety by integrating an airborne Global Positioning System/Inertial Movement Unit (GPS/IMU) with a C-band transponder to downlink time-space-position information (TSPI) via FPS-16 instrumentation radar. This improves current telemetry links and the Range Application Joint Program Office (RAJPO) data link for downlinking TSPI because of the inherent long-range advantage of the radar. The goal of the project is to provide distance independent accuracy, and to demonstrate continuous 15-meter or better position accuracy over the entire flight envelope out to slant ranges up to 1,000 Km with at least 50 updates per second. This improves safety coverage for the wide area flight testing. It provides risk reduction for the Air Force Flight Test Center (AFFTC), Edwards Air Force Base, California and other ranges planning TSPI system upgrades.
    • IMPROVEMENTS IN AUTOMATIC MODULATION RECOGNITION OF ASK AND FSK SIGNALS

      Simms, Dennis; Kosbar, Kurt; Garmin International; University of Missouri, Rolla (International Foundation for Telemetering, 2000-10)
      An algorithm for automatic modulation recognition of ASK, PSK and FSK was developed by Azzouz and Nandi. The algorithm has some serious problems at SNR of 10 dB and below. This paper describes a modification to the algorithm that significantly improves the performance for detection of ASK and FSK at moderate and low SNR.
    • ANTENNA CONTROL FOR TT&C ANTENNA SYSTEMS

      Kaiser, Julius A.; Herold, Fredrick W.; Fredrick Herold and Associates, Inc. (International Foundation for Telemetering, 2000-10)
      A thinned array sensor system develops error voltages for steering dish antennas from signals arriving over a broad range of angles, thereby eliminating need for a priori knowledge of signal location.