Browsing International Telemetering Conference Proceedings, Volume 43 (2007) by Subjects
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BENEFITS AND TECHNIQUES FOR INCREASED POWER EFFICIENCY IN MODERN TELEMETRY TRANSMITTERSWith recent developments in telemetry transmitter technologies, significantly greater DC to RF power efficiencies can be achieved. These new high efficiency transmitter designs may impact overall system design trade-offs by reducing the system size and weight requirements for batteries, heat sinks, and cabling. Furthermore, these fully DC isolated, next generation ARTM Tier 0, I and II enabled devices offer unique options to the platform designer in EMI/EMC control and system design. Advanced manufacturing techniques coupled with adaptive microprocessor control promises enhanced functionality, improved performance and reduced unit costs. The paper presents the performance of a new, high efficiency, telemetry transmitter topology and the possible system benefits involved with the application of this advanced transmitter technology within modern and legacy telemetry platforms. Specific sub-assembly circuit design techniques will be discussed and compared with prior design approaches.
THE EVALUATION AND INTEGRATION OF AN INSTRUMENTATION AND TELEMETRY SYSTEM WITH SOQPSK MODULATION AND CONTROL INTEGRATED WITH AVIONICS DISPLAYSThis paper describes the integration activities associated with the instrumentation and telemetry system developed for an F/A-18 Hornet Flight Test program, including bench integration, avionics integration, and aircraft ground and flight checkout. The system is controlled by a Boeing Integrated Defense System (IDS) Flight Test Instrumentation designed Instrumentation Control Unit (ICU), which interfaces to an avionics pilot display and Ground Support Unit (GSU) to set up the instrumentation during preflight and control the instrumentation during flight. The system takes in MIL-STD-1553, analog parameters, Ethernet, Fibre Channel, and video, and records these with onboard recorders. Selected subsets of this data may be routed to the telemetry system, which features two RF streams, each of which contains up to four PCM streams combined into a composite by a data combiner. The RF streams are transmitted by multi-mode digital transmitters capable of PCM-FM or Shaped Offset Quadrature Phase Shift Keying (SOQPSK), with selectable Turbo-Product Code (TPC) Forward Error Correction (FEC). This paper describes integration of the system with the IDS Flight Test Integration Test Bench (ITB), production avionics integration facilities, and final aircraft ground checkout and initial flight tests. It describes results of integration activities and bench evaluation of the telemetry system.
HIGH-RATE WIRELESS AIRBORNE NETWORK DEMONSTRATION (HiWAND) FLIGHT TEST RESULTSAn increasing number of flight research and airborne science experiments now contain network-ready systems that could benefit from a high-rate bidirectional air-to-ground network link. A prototype system, the High-Rate Wireless Airborne Network Demonstration, was developed from commercial off-the-shelf components while leveraging the existing telemetry infrastructure on the Western Aeronautical Test Range. This approach resulted in a cost-effective, long-range, line-of-sight network link over the S and the L frequency bands using both frequency modulation and shaped-offset quadrature phase-shift keying modulation. This paper discusses system configuration and the flight test results.
PERFORMANCE COMPARISON OF SOQPSK DETECTORS: COHERENT VS. NONCOHERENTShaped Offset Quadrature Shift Keying (SOQPSK) is a spectrally efficient modulation that has been promoted in the airborne telemetry community as a more spectrally efficient alternative for legacy PCM/FM. First generation demodulators for SOQPSK use coherent detectors which achieve good bit error rates at the expense of long synchronization times. This paper examines the performance of a noncoherent SOQPSK detector which significantly improves the signal acquisition times without impacting BER performance in the AWGN environment. The two detection methods are also compared in their ability to combat other channel impairments, such as adjacent and on-channel interference.