Jones, Charles H.; Gardner, Lee S.; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      How difficult is it to develop a pulse code modulation (PCM) stream data format? Specifically, given a size, in bits, and a set of parameter sample rates, how hard is it to find a mapping of the sample rates that fits into the frame size -- if one even exists? Using telemetry trees this paper will show that the number of possible mappings for a given set of parameters and sample rates grows exponentially in terms of the number of parameters. The problem can thus be stated in terms of finding a specific instance, or showing that no such instance exists, among an exponentially large number of potential mappings. Although not proof, this provides strong evidence that the PCM format design problem is NP-complete (meaning it is a member of nondeterministic polynomial space but not a member of deterministic polynomial space). That is, that the problem can not be solved in polynomial time and would take a computer years or centuries to solve relatively small instances of the problem. However, if the problem requirements are relaxed slightly, telemetry trees can be used to reduce the PCM formatting problem to linear time in terms of the number of parameters. This paper describes a technique that can provide an optimal and fully packed PCM format.
    • Development Goals for a Digital Airborne Recorder

      Smith, Darren C.; Tenderholt, Dean; Naval Air Warfare Center - Weapons Division; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      This paper addresses the development requirements for a digital recorder to be used for fighter environment and attack Helicopter applications. This development is focused on triservice requirements to allow for a common system to meet the needs of various test centers.

      Youssef, Ahmed H.; McNamee, Stuart A.; Bowman, Dalphana; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      This paper describes the status of the Edwards Digital Switch (EDS) [1] and the success of the Digital Switch Sustainment Program (DSSP); a multi-service program aimed at cost-effective means for providing maintenance and development of an advanced digital switching system. This digital communications switching system is deployed at the mission control centers of Edwards AFB, Eglin AFB, and China Lake Naval Air Warfare Center (NAWC). Each system provides the test ranges with mission-critical voice communications and Time Space Position Information (TSPI) switching. Through user-friendly Graphical User Interfaces (GUIs), the switch provides exceptional resource management of radios, telephones, user positions, secure communications, radars, trackers, 4-wire Ear & Mouth (E&M) devices, subscriber services, and other equipment. Developed using commercial equipment, such as the Lucent Technologies Digital Access and Cross-Connect System (DACS) II, the digital switch can integrate and interface with the technologies of other test ranges and customers. The DSSP sustaining engineering contract, a $10M contract awarded in 1997, is a multi-service effort in supporting cost effective maintenance and enhancement for the systems’ software and hardware. Eglin and China Lake have agreed to participate in a Digital Switch Working Group (DSWG) to ensure that this configuration management is in place and that all players follow the same system migration path. These ranges and other interested ranges that agree to purchase systems off the contract and participate in the working group will continue to derive benefits by reducing overhead and eliminating the duplication of effort involved in separate endeavors.

      Siu, David P.; Edwards Air Force Base; Computer Sciences Corporation (International Foundation for Telemetering, 1997-10)
      The older F16 jet fighters are currently being flight tested to evaluate the upgraded electronics for aircraft avionics, flight control and weapons systems. An instrumentation system capable of recording three different video signals, recording four Military- Standard-1553B (Mil-Std-1553B) data streams, recording one PCM stream, transmitting the PCM stream, and transmitting two video signals was needed. Using off the shelf equipment, the F16 instrumentation system was design to meet the electronic specifications, limited available space of a small jet fighter, and limited space in the SBand frequency range.

      Chalfant, Timothy A.; Irving, Charles E.; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      The system throughput capacities of modern data systems exceed the bit rate capacity of current range telemetry capabilities. Coupling this with the shrinking spectrum allocated for telemetry results in a serious problem for the Test, Training, and Space telemetry users. Acknowledging this problem, the Department of Defense (DoD) has embarked on an aggressive improvement and modernization program that will benefit both the government and commercial range providers and users. The ADVANCED RANGE TELEMETRY (ARTM) program was created and funded by the Central Test and Evaluation Investment Program (CTEIP) under the Office of the Secretary of Defense, Undersecretary for Acquisition and Technology to address this problem. The ARTM program goals are to improve the efficiency of spectrum usage by changing historical methods of acquiring telemetry data and transmitting it from systems under test to range customers. The program is initiating advances in coding, compression, data channel assignment, and modulation. Due to the strong interactions of these four dimensions, the effort is integrated into a single focused program. This paper describes the ARTM program and how academia research, emerging technology, and commercial applications will lay the foundation for future development.

      Eslinger, Brian; McCombe, Joleen; Edwards Air Force Base (International Foundation for Telemetering, 1997-10)
      The growing need to transmit larger telemetry streams from the receiving site to the processor location over greater distances is requiring newer and more creative techniques. This paper reports efforts to use Asynchronous Transfer Mode (ATM) technology and inverse multiplexing to provide an economical system to interface telemetry streams into the public network for reliable transmission. Cost savings are available immediately for programs that are willing to meet the synchronization criteria today. Lab testing has shown the feasibility of using cost efficient techniques for data transmission. This document describes the investigation that is currently underway that could provide a significant change to the way telemetry data is transmitted from receiver sites to data processing sites. Instead of using dedicated lines with dedicated bandwidth regardless of the program being supported, the approach that has been tested in a lab environment would allow the dynamic allocation of bandwidth using ATM over a variety of carrier services. The combination of ATM and inverse multiplexing allows telemetry data rates above 1.5 Megabits per second (Mbps) to be transmitted over multiple T1 (1.544 Mbps) lines. Previously, the only choice when data rates exceeded 1.5 Mbps was to use an entire DS-3 (45 Mbps). Now it is possible to transmit intermediate sized data rates (1.5 to 8 Mbps) by bonding multiple T1s to provide the desired data throughput.