• A Time Correlated Approach to Adaptable Digital Filtering

      Grossman, Hy; Pellarin, Steve; Teletronics Technology Corporation (International Foundation for Telemetering, 2006-10)
      Signal conditioning is a critical element in all data telemetry systems. Data from all sensors must be band limited prior to digitization and transmission to prevent the potentially disastrous effects of aliasing. While the 6th order analog low-pass Butterworth filter has long been the de facto standard for data channel filtering, advances in digital signal processing techniques now provide a potentially better alternative. This paper describes the challenges in developing a flexible approach to adaptable data channel filtering using DSP techniques. Factors such as anti-alias filter requirements, time correlated sampling, decimation and filter delays will be discussed. Also discussed will be the implementation and relative merits and drawbacks of various symmetrical FIR and IIR filters. The discussion will be presented from an intuitive and practical perspective as much as possible.

      Hedricks, Michael J.; Sussex, Jeff; Streich, Ronald G.; Vandenberg AFB (International Foundation for Telemetering, 2006-10)
      The transition of PCM recording from analog to digital recorders was completed at many test ranges more than a decade ago as marked by delivery of data on S-VHS tape, CD-ROM, DVD, ZIP disc, JAZ disc, 8mm tape and DLT tape for low rate data and D-1 cassettes for high rate data. Data then quickly began distribution via the internet and other networks. Analog recorders have remained a necessary legacy for the long transition to convert from analog to digital (PCM) data transmission from the test vehicles. However, the new digital recorder capabilities have removed this requirement to convert the transmissions from the test vehicle. Analog signal and predetection recording on digital recorders has been successfully demonstrated at costs below the existing analog recorders. Application of new techniques in a methodical transition program to the new digital recorders has proven the many benefits of recording wider bandwidths with excellent repeatability. Repeatability issues are primarily in the very low error sources of the processing system because the major analog error sources of the analog tape recorders, analog time code readers, analog demodulators, etc have been greatly reduced. This paper provides test results of recording higher signal rates and bandwidths of the new programs and describes the techniques and implementation through procedures of the Western Range transition from analog to digital recorders. Surprising results show predetection and analog signal recording costs are nearly the same as PCM recording costs due to the price of deliverable media with respect to mission recording requirements.
    • Translation of L and S Band Tracking Assets to X Band High Dynamic Testing

      Winstead, Michael (International Foundation for Telemetering, 2006-10)
      Recent Constraints on the use of L and S band spectrum led to the search for additional Frequency Domain Bandwidth augmentation for test range telemetry needs. The ITU (International Telecommunications Union) approved X band region is listed as 7000 MHz to 8500 MHz for telemetry space applications. Bandwidth is available within this domain subject to the WARC (World Administrative Radio Consortium) approvals. This paper describes tests and presents results illustrating methodology that is available, and which can be used for conversion of S-band assets to the X band spectral region.

      Beard, Randal W.; Taylor, Clark N.; Bradley, Justin; Prall, Breton; Brigham Young University (International Foundation for Telemetering, 2006-10)
      Brigham Young University recently introduced a project for undergraduates in which a miniature unmanned aerial vehicle system is constructed. The system is capable of autonomous flight, takeoff, landing, and navigation through a planned path. In addition, through the use of video and telemetry collected by the vehicle, accurate geolocation of specified targets is performed. This paper outlines our approach and successes in facilitating this accomplishment at the undergraduate level.
    • Unscented Filter for OFDM Joint Frequency Offset and Channel Estimation

      Iltis, Ronald A.; University of California (International Foundation for Telemetering, 2006-10)
      OFDM is a preferred physical layer for an increasing number of telemetry and LAN applications. However, joint estimation of the multipath channel and frequency offset in OFDM remains a challenging problem. The Unscented Kalman Filter (UKF) is presented to solve the offset/channel tracking problem. The advantages of the UKF are that it is less susceptible to divergence than the EKF, and does not require computation of a Jacobian matrix. A hybrid analysis/simulation approach is developed to rapidly evaluate UKF performance in terms of symbol-error rate and channel/offset error for the 802.11a OFDM format.

      Morrison, Thomas M.; JT3, Edwards AFB (International Foundation for Telemetering, 2006-10)
      Telemetry data are usually collected for analysis at some later time and can be monitored to follow the progress of a test. In the case of an Air Data System the signals from the sensors are sent to a computer that calculates the air data parameters for use on multiple LabView-generated displays, as well as to the Data Acquisition System. The readouts on the multiple displays need to be real-time so they are useful to the flight crew. Equations that control the different air data values are determined by what telemetry data are available and the preference of those doing the test planning. These systems need to display the information in a format useful to the flight crew and be reliable.

      Pillai, Sreelal Sreedharan; Sankarattil, Sreekumar; Padmanabhan, Padma; Rao, Vinod Padmanabha; Pillai, Sivasubramonia; Pillai, Madaswamy; Kollamparambil, Damodaran; Kurian, Thomas; Thirunavukkarasu, Chidambaram; Indian Space Research Organization (International Foundation for Telemetering, 2006-10)
      We describe the design and development of a baseband telemetry system for multistage launch vehicles. The system is organized as a three tier one with remote data acquisition and processing units and a centralized control unit. The front-end Data Acquisition Units (DAUs) feature software programmable amplification, offset, filtering and sensor excitation and thus are flexible to interface directly to a variety of sensors used in launch vehicles. The Data Processing Units (DPUs) gather data from DAUs through a serial link compatible to RS-485 standards and carry out a variety of data analysis and data compression functions on selected channels under software control. The central Telemetry Control Unit (TCU) receives this data through a transformer isolated link compatible to MIL-1553B standards and performs the functions of data delay, data storage, onboard computer data monitoring, PCM formatting and pre-modulation signal conditioning to achieve miniaturization. The configuration and features of this telemetry system make its integration simple without compromising on data integrity and reliability and suit the adoption of futuristic technologies and concepts such as smart sensor networks, adaptability, reconfiguration and vehicle health management.

      Xiangwu, Gao; Juan, Lin; Zhengguang, He; Beijing Institute of Astronautical Systems Engineering; China Academy of Launch Vehicle Technology (International Foundation for Telemetering, 2006-10)
      XX launch vehicle has been flying onboard video system which includes video cameras, data compression devices and channel switch device for the second Chinese spaceflight. The camera is a PAL analog camera that been sampled and compressed by compression device. The compressed digital video data is combined with telemetry data into the telemetry radio channel. Lighting is provided by sunlight, or a light has been equipped when sunlight is unavailable. IRIG-B timing is used to correlate the video with other vehicle telemetry. The video system’s influences to the vehicle flight have been decreased to minimum.

      Jones, Charles H.; Edwards Air Force Base (International Foundation for Telemetering, 2006-10)
      The availability of spectrum has been decreasing while requirements have been increasing. One way of answering the question of how much impact this has is to ask how much spectrum would be used in an ideal situation. A way of getting a handle on this question is to look at how much data is recorded onboard test vehicles. We can assume that, if we could, we would transmit everything we currently record. This would be ideal since we could then consider the onboard recorders as backup and we would have all data available in case of catastrophe. This paper looks at onboard recording and telemetry trends to see what percentage of data has been and will be telemetered. This analysis involves several levels in that telemetry requirements are not limited to transmission over a single frequency. It is common to have more than one vehicle involved in an operation. Thus, different scenarios are evaluated from single vehicle operations to larger scale test and training operations. When considered from this point of view, the impact becomes quite clear: the T&E community is making significant compromises on telemetering data. Therefore, current efforts to obtain more spectrum for telemetry use through the World Radio Conference are well justified.

      Chaildin, Mark; Inter-Coastal Electronics (International Foundation for Telemetering, 2006-10)
      For several decades, the military has used the Multiple Integrated Laser Engagement System (MILES) with a series of iR sensors along a belt fastened to a vehicle for training and simulation. Now, an alternative to this legacy system, a solar rechargeable battery powered wireless IR sensor is replacing wired sensors. The use of short-range RF communications network, allows the MILES sensors strategic placement about a combat vehicle without the umbilical cabling normally required for power and signal coupling from the players processing unit. The RF network operates in the 340 to 380 MHz band, has channeling capability of over 1600 channels, and coexists with the vehicles on board high-powered radios without interference. The wireless sensor implements a custom designed IR sensing amplifier, designed for maximum sensitivity and minimal power dissipation, along with advanced semiconductor IC’s for signal processing and power conversion. Solar recharging enables the sensor to operate for extended time, on a single battery that should last for years without replacement. A proprietary software protocol, developed for communication integrity, is a critical part of the overall system and supports other sensor types and control elements with low data rates for a wireless Vehicle Area Network. The system, successfully installed on several military training platforms, proves to be a viable product for military training and simulation systems for the 21st century.
    • Wireless Sensor System for Airborne Applications

      Berdugo, Albert; Grossman, Hy; Schofield, Nicole; Musteric, Steven; Teletronics Technology Corporation; Eglin Air Force Base (International Foundation for Telemetering, 2006-10)
      Adding an instrumentation / telemetry system to a test vehicle has historically required an intrusive installation for wiring and powering all elements of the system from the sensor to the telemetry transmitter. In some applications there is need for a flexible and modular instrumentation and telemetry system that can be installed with minimal intrusiveness on an aircraft without the need for permanent modifications. Such an application may benefit from the use of a miniaturized, inexpensive network of wireless sensors. This network will communicate its data to a central unit installed within the aircraft. This paper describes recent efforts associated with the Advanced Subminiature Telemetry System (ASMT) Initial Test Capability Project. It discusses the challenges in developing a wireless sensor network system for use in an airborne environment. These include selection of frequencies, COTS wireless devices, batteries, system synchronization, data bandwidth calculations, and mechanical structure for external installation. The paper will also describe the wireless network architecture as well as the architecture of the wireless sensor and the central control unit.
    • XidML – Two Years On

      Corry, Diarmuid; Acra Control Inc. (International Foundation for Telemetering, 2006-10)
      In 2004 ACRA CONTROL introduced XidML as a published standard for instrumentation definition via XML. After two years in the field, much feedback and two revisions, this paper outlines where the standard is now, some of the lessons learned and discusses some ideas for where next. XidML allows any package, message or frame to be defined including PCM, MIL-STD- 1553, Ethernet and storage formats, it is also used to define the settings for instrumentation as diverse as Analog to Digital modules, MIL-STD-1553 monitors, PCM encoders, recorders, bit-syncs, and decoms. Importantly it facilitates the EU range and data format to be defined for large parameter lists. The key elements in the standard are discussed along with some lessons learned.