• Channel Based Sampling in a Network Based Data Acquisition System

      Sulewski, Joseph; Dehmelt, Chris; L-3 Communications Telemetry East (International Foundation for Telemetering, 2013-10)
      Over the last few years, PCM based data acquisition systems have become known as "Traditional PCM" systems. This terminology modification is a sign of the evolution of the next generation of telemetry/data acquisition systems based on network topologies. This has come about due to users clamoring for functionality that has not been available in the traditional systems, such as supporting increased data rates, providing access to onboard archived data, supporting on-the-fly reconfiguration, and simplifying data distribution and delivery. The iNET standard is using standard network technology to improve device interoperability and data acquisition. To minimize impact on existing data acquisition system devices, the initial effort of this approach has included the transmission of "Traditional" fixed PCM frames within a network message based structure. This approach, however, squanders network bandwidth, as a PCM frame includes all samples of all channels, and requires significant processing power for even simple tasks. Delivering on the promise of a more flexible transmission method requires a change in how data is acquired in the data acquisition devices. The iNET standard defines such a packet based transport system, which supports channel based packet formats besides "Traditional PCM" to efficiently deliver data products. This paper will provide background on the benefits of these methods and an overview of methods by which these formats can be implemented.
    • Evaluation of CMA+AMA Equalization for SOQPSK Modulation in Aeronautical Telemetry

      Cole-Rhodes, Arlene; Moazzami, Farzad; KoneDossongui, Serge; Opasina, Oladotun; Umuolo, Henry; Betelle, Habtamu; Thang, Solomon; Shrestha, Robin; Morgan State University (International Foundation for Telemetering, 2013-10)
      Multipath interference continues to be the dominant cause of telemetry link outages in low-elevation angle reception scenarios. The most reliable and universally applicable solution to this problem is in the form of equalization. Previous work in this area has considered the Constant modulus algorithm (CMA) equalizer operating in a blind adaptive mode. To the extent that knowledge of the multipath channel improves the performance of CMA and related equalizers and permits the use of other equalization techniques, data aided equalizers are of interest. Channel knowledge is obtained by comparing the received samples with the samples corresponding to a known bit pattern (called a pilot block) periodically inserted in the telemetry data stream. The main objective of this research is to evaluate the performance of a modified CMA equalization algorithm, which has the property of automatically resolving the phase of the QPSK modulated symbol, and to determine its suitability for use with SOQPSK-TG by taking into account the capability of exploiting the presence of a periodically inserted pilot block. As an initial effort in that direction, this paper provides simulation results of the error performance of the blind linear combination of CMA and alphabet matched algorithm (AMA) equalizer as compared to that of pilot assisted equalization with SOQPSK modulation over aeronautical channel.
    • Next Generation End to End Avionics Bus Monitoring

      Rodittis, Kathy; Cooke, Alan; Symvionics Inc.; Curtiss-Wright Controls Avionics & Electronics (International Foundation for Telemetering, 2013-10)
      With the advent of networked based data acquisition systems comes the opportunity to acquire, transmit and store potentially very large volumes of data. Despite this, and the increased size of the data acquisition networks, the use of tightly integrated hardware, and setup and analysis software enable the FTI engineer to save time and increase productivity. This paper outlines how the use of innovative bus packetizer technology and the close integration of FTI software can simplify this process. The paper describes how packetizer technology is used to acquire data from avionics buses, and how it packages this data in a format that is optimized for network based systems. The paper further describes how software can simplify the process of configuring avionics bus monitors in addition to automating and optimizing the transport of data from various nodes in the acquisition network for transmission to either network recorders or via a telemetry link.
    • Telemetry Network Intrusion Detection Test Bed

      Dean, Richard; Moten, Daryl; Moazzami, Farhad; Morgan State University (International Foundation for Telemetering, 2013-10)
      The transition of telemetry from link-based to network-based architectures opens these systems to new security risks. Tools such as intrusion detection systems and vulnerability scanners will be required for emerging telemetry networks. Intrusion detection systems protect networks against attacks that occur once the network boundary has been breached. An intrusion detection model was developed in the Wireless Networking and Security lab at Morgan State University. The model depends on network traffic being filtered into traffic streams. The streams are then reduced to vectors. The current state of the network can be determined using Viterbi analysis of the stream vectors. Viterbi uses the output of the Hidden Markov Model to find the current state of the network. The state information describes the probability of the network being in predefined normal or attack states based on training data. This output can be sent to a network administrator depending on threshold levels. In this project, a penetration-testing tool called Metasploit was used to launch attacks against systems in an isolated test bed. The network traffic generated during an attack was analyzed for use in the MSU intrusion detection model.
    • Telemetry Network System (TMNS) Link Management Algorithm Verification

      O'Connell, Ray; RoboComAI LLC (International Foundation for Telemetering, 2013-10)
      Telemetry Network System (TmNS) contains a centralized link manager which allows efficient use of the frequency spectrum by dynamically allocating capacity to transmit based on need and priority. To verify the accurate operation of the telemetry system link management algorithm prior to system demonstration, a combination of novel techniques were leveraged in the areas of modeling and simulation, and test bed verification. This paper will cover the process of verifying the link management algorithm from the use of the OPNET iNET simulation to test bed radio simulators along with the developed test bed tools used to capture the results.
    • Variable Rate OFDM Performance on Aeronautical Channels

      Moazzami, Farzad; Cole-Rhodes, Arlene; Dean, Richard; Elrais, Mostafa; Mengiste, Betelhem; Guatam, Bibek; Damiba, Eugene; Morgan State University (International Foundation for Telemetering, 2013-10)
      This paper shows the design and testing of a test bed at Morgan State University as part of the development of a Link Dependent Adaptive Radio (LDAR). It shows the integration of variable rate QAM/OFDM modulation and a variable rate Punctured Convolutional Coder. It also shows a dynamic aeronautical channel simulator developed to capture the dynamics of these channels. Performance results are show for combinations of modulation, coding and channel variations that provide motivation for the potential of the LDAR system.