International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A typical telemetry system for aircraft flight-testing transmits one or several data streams to the ground for real-time display and analysis, and also records the same stream onboard for later playback. During test operations, only a fraction of the available data is used at any given time for real-time display or analysis. More efficient use of the RF channel could be realized if only the data needed for the current test point is transmitted, rather than the entirety of the data. Intelligent selection of a subset of the data stream can provide large reductions in the required telemetry downlink bandwidth. As one of the Advanced Range Telemetry (ARTM) On-Board Data Management (OBDM) initiatives, a prototype on-board data selection subsystem is being developed and demonstrated. The demonstration utilizes COTS telemetry workstations to the maximum extent possible and includes “plug-in” data requestor, selection, and server components to implement the added DML functionality. A significant objective of the OBDM/DML project will be to validate RF channel models to help minimize the amount of flight-testing necessary to validate the DML concept. This paper will discuss the OBDM/DML architecture, integration of several custom components with the COTS portions of the ARTM “test bench”, and the current status of the OBDM/DML development and test program.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As the number of telemetry applications at sites increases, the need for a higher bandwidth link from site-to-site grows. The use of an inverse T1 multiplexer allows the site to utilize multiple T1 lines rather than more costly higher bandwidth lines. There are many advantages to using a recognized packet standard, such as IRIG-107/98, over simply routing the streams through T1 lines. One advantage is that there is a total separation of data stream clock from T1 transmission clock, reducing synchronization circuitry and overhead. Another advantage is that the use of packets also allows for a smooth reconstructed clock phase on the receiving site, creating a virtually seamless transmission of clock and data. And, finally, by using a recognized packet standard, the inverse T1 multiplexer may easily be integrated into ranging and telemetry systems already incorporating packetized telemetry. This paper will discuss the combination of packets and inverse multiplexing to achieve an expandable transmission system capable of delivering a high bandwidth data stream across multiple T1 lines.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As testing requirements on the ranges require ever more sophisticated cross correlation of data from multiple data acquisition sources, it becomes increasingly advantageous to collect and disseminate this information in a more network oriented fashion. This allows any of the data collected at physically separated sites to be used simultaneously at multiple mission control or data reduction centers. This paper presents an approach that maximizes the use of legacy communication paths and data reduction systems to support an evolutionary migration toward the day when testing can take full advantage of commercial communication protocols and equipment such as OC-3, ATM, etc. One key element of this approach is the packetizing of data at each reception point to provide virtual circuit switching using packet routing. Based on the newly adopted IRIG/RCC 107-98 standard, the system may even be expanded all the way back to the actual sensors. The second key element is the use of the readily available time and timing pulses based on GPS to establish a uniform sampling interval that will allow the cross correlation of data received at different points spread over a wide area.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A digital feedback system used to monitor and control a high energy electron beam’s orbit and stability in a VUV and X-ray storage ring will realize a 10 fold increase in the feedback system response time using packetized (IRIG 107-98) telemetry. The improvement in feedback time will provide a significant improvement in the level of orbit stability. This paper discusses the advantages of using a packetizing standard and high speed data acquisition as a cost effective way to support the scientific community in their real time processing needs.