• CHANNEL ESTIMATION USING GAUSSIAN PROCESS REGRESSION

      Kim, Taejoon; Perrins, Erik; Simeon, Richard; Univ Kansas, Dept Electrical Engineering and Computer Science (International Foundation for Telemetering, 2019-10)
      Gaussian process (GP) regression can be used in the interpolation of observed periodic channel estimates in OFDM transmission systems over both time and frequency in small-scale fading environments. Previous GP regression studies used the popular radial basis function as the GP kernel. In this study, we examine the performance of GP regression using a Bessel kernel with a semi-static hyperparameter vector. Results show that GP regression using the Bessel kernel outperforms the radial basis kernel, as well as traditional interpolation methods such as cubic spline and FIR interpolation, especially when training symbols are spaced far apart in time with respect to the channel coherence time.
    • CLASSIFICATION STYLE REGRESSION FOR SPECTRAL OPENING PMF ESTIMATION

      Fosdick, Garrett; Marefat, Michael; Bose, Tamal; Univ Arizona, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      Dynamic spectrum allocation (DSA) permits unlicensed users to access spectrum owned by a licensed user given they do so without interference to the primary user. To avoid interference with other users, the unlicensed user needs to be aware of channel availability. Spectrum sensing allows a radio to find spectrum holes, but costs energy and time. Predictive methods can be used to decrease the amount of spectrum sensing needed to find an available channel. We designed a novel neural network architecture for spectrum hole prediction. This neural network is capable of creating probability mass functions (PMF) estimates of the length of channel openings with no assumptions of the initial probability distribution or prior knowledge about the traffic. This architecture is shown to work through a mathematical proof, and its performance is measured through simulation.
    • CO-EXISTENCE OF AERONAUTICAL MOBILE TELEMETRY AND LTE SYSTEMS IN THE S-BAND

      Shoudha, Shamman Noor; Saquib, Mohammad; Univ Texas, Dept Electrical Engineering (International Foundation for Telemetering, 2019-10)
      This paper analyzes the effect of Long-Term Evolution (LTE) uplink interference on the performance of Aeronautical Telemetry S-band users. A MATLAB simulation environment is used to analyze the interference effect using SOQPSK-TG and 64-QAM modulation schemes for telemetry and LTE transmitters, respectively. An ideal Surface Acoustic Wave (SAW) filter followed by a 2-by-2 symbol detector is used in the telemetry receiver. To ensure a target bit error rate (BER) of 10-5, depending on the LTE spectrum mask, the Carrier-to-Interference (C/I) ratio requirement is -15.4, -32.4 and -30 dB for data rates 1; 5 and 10 Mbits/s, respectively.
    • CONTROL FAILURES IN AN UNMANNED AERIAL SYSTEM AND THE POTENTIAL FOR STATELESS CONTROL

      Marcellin, Michael; Norland, Kyle; Univ Arizona, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      To participate in the 2019 SUAS competition, an Unmanned Aerial System (UAS), was built. Unfortunately, several critical failures occurred, including an unwanted circling behavior, and an unnecessary self-crash. The analysis of both behaviors revealed surface level errors in the scripts and devices that were used, but also a deeper flaw in the architecture of state based behaviors and conditional state transitions. To address these failures, an alternative architecture based around stateless controls was designed and tested. It successfully resolved the issues, and seems to hold promise as an alternative control system architecture, especially in non-linear environments.
    • CSI Estimation Using Artificial Neural Network

      Gajjar, Viraj; Kosbar, Kurt; Missouri University of Science and Technology (International Foundation for Telemetering, 2019-10)
      We propose using machine learning to estimate channel state information (CSI) for MIMO communication links. The goal is to use information such as atmospheric conditions, amount of path loss, and Doppler shift to improve the accuracy of CSI estimates. We start by designing an algorithm which estimates the CSI based on previously mentioned factors. Using this algorithm, we simulate a dataset of CSI over varying atmospheric conditions, receiver position, and receiver velocity. We then use this dataset to train an artificial neural network, which is able to estimate the CSI by using the current atmospheric condition, receiver position, and velocity.
    • CYBERDEFENSE AND DATA SECURITY IN FLIGHT TEST APPLICATIONS

      Weir, Malcolm; Ampex Data Systems Corporation (International Foundation for Telemetering, 2019-10)
      Specialist test establishments have historically placed significant reliance on “security through obscurity”. With increasing “always on” connectivity and the drive to leverage commercial products, the threat space has widened significantly while the sophistication of attack vectors has evolved. Access through vulnerabilities embedded within a platform’s communications, flight controls, or other on-board access points leave organizations vulnerable to attack, exploitation, and loss of revenue or property. Cyber and operational security associated with all aspects of aircraft technologies is becoming increasingly critical. This paper investigates techniques and procedures by which aircraft and space vehicles can be compromised by and protected against cyber-attacks.
    • DATA COLLECTION AND ANALYSIS TECHNIQUES FOR SOLAR CAR TELEMETRY DATA

      Rouse, Michael; Sauer, Miranda; Kosbar, Kurt; Missouri University of Science and Technology, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      Data collected from a solar car is monitored in real-time, which allows for intelligent decision making, efficient debugging, and high-quality testing for solar car teams. This paper compares three databases (MySQL, PostgreSQL, and MongoDB) to determine the optimal database system that should be used at solar car competitions. Each database system was tested using simulated solar car data to measure read and write speeds, and quality of performance on a low-power computer. Data were analyzed and displayed with custom interfaces to improve the user experience at solar car competitions.
    • DECORRELATION DEEP LEARNING FOR FINGERPRINT-BASED INDOOR LOCALIZATION

      Kim, Taejoon; Perrins, Erik; Xiong, Guojun; Univ Kansas, Dept Electrical Engineering and Computer Science (International Foundation for Telemetering, 2019-10)
      Indoor localization is of particular interest due to its immense practical applications. However, the rich multipath and high penetration loss of indoor wireless signal propagation make this task arduous. Though recently studied fingerprint-based techniques can handle the multipath effects, the sensitivity of the localization performance to channel fluctuation is a drawback. To address the latter challenge, we adopt an artificial multi-layer neural network (MNN) to learn the complex channel impulse responses (CIRs) as fingerprint measurements. However, the performance of the location classification using MNN critically depends on the correlation among the training data. Therefore, we design two different decorrelation filters that preprocess the training data for discriminative learning. The first one is a linear whitening filter combined with the principal component analysis (PCA), which forces the covariance matrix of different feature dimensions to be identity. The other filter is a nonlinear quantizer that is optimized to minimize the distortion incurred by the quantization. Numerical results using indoor channel models illustrate the significant improvement of the proposed decorrelation MNN (DMNN) compared to other benchmarks.
    • DESIGN AND RESEARCH OF REAL-TIME MONITORING PROGRAM DEVELOPMENT SYSTEM FOR CIVIL AIRCRAFT FLIGHT TEST DATA BASED ON WPF

      Mao, Wei; Feng, Can; Liu, Tao; Wang, Feng; Liang, Jiayi; Flight Test Center of the COMAC, Instrumentation Dept (International Foundation for Telemetering, 2019-10)
      The real-time monitoring program offlight test data is an indispensable and important supporting tool in the flight test of large civil aircraft. With the continuous deepening of the networked test system, a large number of complex flight test parameters pose a huge challenge for the development of monitoring programs. Based on the WPF platform, this paper uses XAML files, reflection and DataBinding to design a system for developing real-time monitoring programs for flight test data. The system realizes the rapid integration and management of the monitoring program by dragging and displaying the control, shortening the preparation cycle in the past few weeks to several hours; when the system is running, the three-layer architecture can drive hundreds of monitoring terminals in real time, which is the domestic large-scale passenger aircraft C919 aircraft. The first flight and forensic flight test provided technical support.
    • Design of Airborne Real-time Monitoring System for Vibration Signal of Large Civil Aircraft

      Jiayi, Liang; COMAC Flight Test Center, Instrumentation Dept (International Foundation for Telemetering, 2019-10)
      The high frequency vibration signal can effectively reflect the structural strength of aircraft during flight test. In order to meet the need of real-time monitoring of vibration parameters of a large civil airliner, an airborne real-time monitoring system for vibration signals is designed and developed. Development of airborne real-time monitoring software for high-frequency signals was based on C#. The software received and analyzed the network data of the airborne acquisition system, processed the time domain signals by FFT and power spectrum transformation, and realized the graphical display. The software can provide a strong support for the monitoring person to know the status of the aircraft in time.
    • DESIGN OF PROBING WAVEFORMS IN SOFTWARE-DEFINED SENSING AND IMAGING SYSTEMS

      Lee, Hua; Univ California Santa Barbara, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      The probing waveforms play a crucial role in the performance of software-defined sensing-imaging systems. The characteristics of the probing waveforms govern both the computation complexity and accuracy of the estimation. This paper describes the concepts of the design and utilization of the probing waveforms for sensing and imaging applications.
    • DESIGNING A TELEMETRY SYSTEM WITH A FOCUS ON EDUCATION

      Marcellin, Michael; Fuehrer, Daniel; Nguyen, James; Schreiber, Andre; Univ Arizona, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      The University of Arizona Baja Racing team competes in an international competition each year. We build a custom telemetry system for the car to collect data during races in order to inform design decisions and warn of upcoming problems. This paper will focus on the contrast between designing a system for production versus designing for the educational experience, as is the ultimate goal of our team. We will specifically discuss this contrast in the areas of size, power consumption, manufacturability, maintainability, repairability, and testability.
    • DEVELOPING WIRELESS IMUS TO SIMPLIFY INTEGRATION INTO DYNAMIC SYSTEMS

      Kosbar, Kurt; Lipina, Jacob; Christmas, Austin; Marcolina, Rebecca; Missouri University of Science and Technology (International Foundation for Telemetering, 2019-10)
      This paper discusses the development of wireless inertial measurement units (IMUs) designed to transmit data from a prototype Mars rover to a remote base station. These nine degree of freedom, multi-chip modules provide measurements for linear acceleration, angular rotation velocity, and magnetic field vectors for the rover’s chassis and robotic arm end-effector. To facilitate integration into these dynamic systems, each unit is independently powered and has a form factor of 108 cc. IMU data is sent from 32-bit microcontrollers with embedded IEEE 802.11 b/g/n Wi-Fi to the rover via UDP transport through a custom publish/subscribe distributed IP protocol. Data is relayed over two circular polarized omnidirectional antennas to the base station’s dual linear MIMO Yagi-Uda antenna. The information gathered provides operators a heading and orientation to improve situational awareness, as camera visuals are often inadequate.
    • DEVELOPMENT OF NETWORK DATA AGGREGATOR FOR PAYLOAD FILTERING TO CONTROL TELEMETRY BANDWIDTH

      Ellerbrock, Phil; Reyzer, Charles; Zettwoch, Bob; Kragick, Andy; Troshynski; The Boeing Company; Avionics Interface Technologies (International Foundation for Telemetering, 2019-10)
      Emerging aircraft avionics and vehicle management communication systems have switched to higher data rate networks such as Ethernet and Fibre Channel, requiring Flight Test systems that can acquire data information from these networks. The data has moved onto higher speed networks, but the telemetry bandwidth has not increased, therefore producing a need to selectively capture data from within a packet, down to the bit level, for telemetry without capturing the entire message. Ethernet and Fibre Channel are transport protocols without rigid payload structure definitions as seen with MIL-STD-1553 or ARINC-429. Avionics traffic can be defined in any manner including dynamic length components or repeating structures that are difficult to define generically. AIT (Avionics Interface Technologies) developed the Airborne Network Data Aggregator (ANDA) unit for The Boeing Company with six different payload structure filter types to generically capture data out of network structures.
    • DFT-BASED FREQUENCY OFFSET ESTIMATORS FOR 16-APSK

      Rice, Michael; Redd, Bryan; Ebert, Jamison; Twitchell, Autumn; Brigham Young University, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      In this paper, we analyze several DFT-based frequency offset estimators for use with the 16-APSK digital modulation scheme. Even a small frequency offset between radio transmitters and receivers can cause phase information to be lost, so a system to align the phases is required to reliably demodulate PSK signals. These estimators have been adapted for 16-APSK from methods originally intended for use with QPSK and CPM. These methods consist of a coarse search and a fine search with an optional dichotomous search to improve accuracy. We analyze the estimator error variance and bit error rate associated with several methods of frequency estimation. These estimators exhibit small estimate error and variance and can provide bit error rates close to the ideal AWGN BER.
    • DIRECT IMPLEMENTATION OF A BIDIRECTIONAL NETWORK COMMUNICATION LINK IN CIVIL AIRCRAFT FLIGHT TEST USING MODIFIED LTE AIR-TO-GROUND SYSTEM

      Du, Xianyu; Deng, Guobao; COMAC Flight Test Center (International Foundation for Telemetering, 2019-10)
      This paper mainly describes a preliminary trial implementation of a bidirectional network communication link for aircraft range flight test application based on modified LTE Air-to-Ground systems. The theoretical feasibility of this trial which integrated the existing on-board network-based acquisition system installed on our regional jet and a newly designed modified LTE Air-to-Ground communication system was carefully analysed and validated before system level ground experiments. Finally, several test flights were performed within a specific airspace with two eNodeBs, which configured as an independent LTE network and covered most of the designed flight path, and the test results give us the conclusion that under the promise of deploying reliable ground base stations, LTE system has the potential capability to provide acceptable bandwidth and time delay performance for range flight test application.
    • DOPPLER POWER SPECTRA FROM VEHICLE-TO-EVERYTHING PROPAGATION EXPERIMENTS

      Rice, Michael; Harrison, Willie K.; Norman, Kalin; Jensen, Benjamin; Brigham Young University, Dept Electrical and Computer Engineering (International Foundation for Telemetering, 2019-10)
      This paper presents the results of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) propagation experiments. The experimental results are summarized by Doppler power spectra. Our measurements indicate the need for a dynamic system that can handle the variable channels experienced in vehicle-to-everything communications.
    • DUAL-CHANNEL RECEIVER PERFORMANCE USING BESTCHANNEL SELECTION: FIELD TEST RESULTS

      Uetrecht, Jim; Quasonix, Inc. (International Foundation for Telemetering, 2019-10)
      Best-Channel Selection (BCS) uses real-time data quality metrics (DQM) to select the best demodulated bits from Channel 1, Channel 2, and the Combiner of dual-channel receivers. Laboratory testing has demonstrated a substantial reduction in bit error rate (BER) relative to individual channels (including the Combiner) under some synthesized link conditions, with no degradation in BER under the remainder of tested link conditions. This paper extends those results to real-world flight tests.
    • EFFECT OF ROTATING PROPELLERS ON TELEMETRY SIGNALS

      Geoghegan, Mark; Nusair, Marwan; Quasonix (International Foundation for Telemetering, 2019-10)
      The migration of aeronautical telemetry systems to C band has prompted a fresh look at many historically uninteresting facets of telemetry links. The effects of higher cable losses and smaller antenna beamwidths, for example, have been recognized and accounted for. Recent flight tests at Edwards AFB with a propeller-driven aircraft have revealed another such effect, which we have termed “prop chop”. Realtime data quality metric (DQM) values showed a periodic fluctuation in DQM, related to the aircraft engine speed. An investigation of this phenomenon using detailed electromagnetic simulation of a transmit antenna in the presence of a propeller shows a mechanism for this interference, both when the propeller is in front of the transmit antenna and when it is behind the transmit antenna. This paper compares the electromagnetic propagation simulation results to measured values from the field.
    • EFFECTS OF SWARM DENSITY ON MULTIHOP DRONE TELEMETRY DATA

      Rohrer, Justin P.; Naval Postgraduate School Monterey, Dept Computer Science (International Foundation for Telemetering, 2019-10)
      Bandwidth being a limited resource in airborne telemetry networks, drone swarms are particularly challenging to instrument due to the number of airborne nodes involved. Even a modest amount of data being transmitted by each node may overwhelm the network. Prior work has evaluated these effects in a number of drone swarm mobility scenarios,and shown the difficulty of achieving reliable data delivery. However, those results do not distinguish between data loss due to congestion of the available spectrum, and loss due to changing network topologies or disconnection due to mobility. In this work we attempt to isolate those effects by keeping a simulated drone swarm stationary,and focussing on the telemetry data delivery due to changing the size and density of the swarm. We compare the performance using no multi-hoprouting protocol, as well as using DSDV, AODV, DSR, and OLSR.