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Full-Text Articles in Engineering
A Survey Of Sparse Channel Estimation In Aeronautical Telemetry, Christopher James Hogstrom
A Survey Of Sparse Channel Estimation In Aeronautical Telemetry, Christopher James Hogstrom
Theses and Dissertations
Aeronautical telemetry suffers from multipath interference, which can be resolved through the use of equalizers at the receiver. The coefficients of data-aided equalizers are computed from a channel estimate. Most channels seen in aeronautical telemetry are sparse, meaning that most of the coefficients of the channel are zero or nearly zero. The maximum likelihood (ML) estimate does not always produce a sparse channel estimate. This thesis surveys a number of sparse estimation algorithms that produce a sparse channel estimate and compares the post-equalizer bit error rates (BER) using these sparse estimates with the post-equalizer BER using the ML estimate. I …
Gpu Implementation Of Data-Aided Equalizers, Jeffrey Thomas Ravert
Gpu Implementation Of Data-Aided Equalizers, Jeffrey Thomas Ravert
Theses and Dissertations
Multipath is one of the dominant causes for link loss in aeronautical telemetry. Equalizers have been studied to combat multipath interference in aeronautical telemetry. Blind equalizers are currently being used with SOQPSK-TG. The Preamble Assisted Equalization (PAQ) project studied data-aided equalizers with SOQPSK-TG. PAQ compares, side-by-side, no equalization, blind equalization, and five data-aided equalization algorithms: ZF, MMSE, MMSE-initialized CMA, and frequency domain equalization. This thesis describes the GPU implementation of data-aided equalizer algorithms. Static lab tests, performed with channel and noise emulators, showed that the MMSE, ZF, and FDE1 show the best and most consistent performance.
Phase 1 Final Report: Preamble Assisted Equalization For Aeronautical Telemetry (Paq), Michael Rice, Mohammad Saquib, Arlene Cole-Rhodes, Farzad Moazzami, Erik Perrins
Phase 1 Final Report: Preamble Assisted Equalization For Aeronautical Telemetry (Paq), Michael Rice, Mohammad Saquib, Arlene Cole-Rhodes, Farzad Moazzami, Erik Perrins
Faculty Publications
This is the Phase 1 report for Preamble Assisted Equalization for Aeronautical Telemetry (PAQ).
Executive Summary:
To fully leverage the benefits of a periodically inserted preamble, the preamble is used to estimate the state of the channel. To this end the following algorithms have been developed, tested in simulation, and ported to the GPU-based real-time system:
1. The preamble detector, which scans the received samples searching for the presence of the preamble. The location of the preamble in the received samples is required to use the received samples to estimate the frequency offset, channel impulse response, and noise variance. The …
Modulation And Synchronization For Aeronautical Telemetry, Christopher G. Shaw
Modulation And Synchronization For Aeronautical Telemetry, Christopher G. Shaw
Theses and Dissertations
Aeronautical telemetry systems have historically been implemented with constant envelope modulations like CPM. Shifts in system constraints including reduced available bandwidth and increased throughput demands have caused many in the field to reevaluate traditional methods and design practices. This work examines the costs and benefits of using APSK for aeronautical telemetry instead of CPM. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. Spectral regrowth in nonlinear power amplifiers when driven by non-constant envelope modulation is also considered. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in …
Automatic Modulation Recognition For Aeronautical Telemetry, Jacob William Frogget
Automatic Modulation Recognition For Aeronautical Telemetry, Jacob William Frogget
Theses and Dissertations
This these explores automatic modulation recognition as applied to PCM/FM, SOQPSK- TG and ARTM CPM. It found that the likelihood based approach is intractable. The statistical features of the amplitude, phase and frequency are ineffective at distinguishing these modulation types. A method based on the phase changes between symbols is developed and shows that as long as symbol timing is established, this method can effectively distinguish PCM/FM, SOQPSK-TG and ARTM CPM for signal-to-noise ratios above 30 dB. Another method, the Bianchi-Loubaton- Sirven technique, was able to distinguish PCM/FM and SOQPSK-TG but was unable to distinguish ARTM CPM. A happy byproduct …
Simulating The Performance Of Tracking A Spinning Missile At C-Band, Darren Robert Kartchner
Simulating The Performance Of Tracking A Spinning Missile At C-Band, Darren Robert Kartchner
Theses and Dissertations
The amplitude fluctuation induced by a spinning missile acts as a disturbance on tracking schemes that use sequential lobing (e.g., conscan). In addition, if a tracking system converts from S-band to C-band, the beamwidth is narrower and the wrap-around antenna on the missile requires more patches, and so the margin of error for tracking decreases. Tracking performance is simulated with a spinning missile with ballistic and fly-by trajectories while running at C-band. The spinning missile causes a periodic component in the pointing error, and when the scan frequency is an integer multiple of the roll rate, several tracking schemes lose …
Wireless Sensor Network Approach To Aeronautical Telemetry, Oluwasegun Babatunde Tinubi
Wireless Sensor Network Approach To Aeronautical Telemetry, Oluwasegun Babatunde Tinubi
Theses and Dissertations
Wireless sensor networks have become a rapidly growing research field in recent years. They are envisioned to have a wide range of applications in military, environmental and many other fields. We examine the performance of wireless sensor network applications to aeronautical telemetry. To date, test ranges have relied on a single telemetry ground station for the reception of packets from all air borne transmitters. We researched an alternate means of achieving this same goal with fewer resources. It is a well known fact that communication power and bandwidth are the most expensive commodities in wireless communications. The telemetry world is …
Final Report: Shf Channel Modeling Over Sea-Based Test Ranges, Qiang Lei, Michael D. Rice
Final Report: Shf Channel Modeling Over Sea-Based Test Ranges, Qiang Lei, Michael D. Rice
Faculty Publications
This work was supported by the Science & Technology Test & Evaluation Spectrum Efficient Technologies Program sponsored by the US Air Force under contract F04611-02-C-0020. Channel sounding data collected from an airborne transmitter over the Pacific Ocean off the coast of Pt. Mugu, Naval Air Station, was analyzed and used to model multipath propagation over the ocean. The experiments showed that at 8.000 GHz, over the water multipath propagation is well modeled by a three-ray propagation model. The first ray (or propagation path) is the line-of-sight propagation path. The second ray is a strong specular reflection determined by the geometry …
Performance Analysis Of Common Detectors For Shaped Offset Qpsk And Feher's Qpsk, Tom Nelson, Michael D. Rice, Erik Perrins
Performance Analysis Of Common Detectors For Shaped Offset Qpsk And Feher's Qpsk, Tom Nelson, Michael D. Rice, Erik Perrins
Faculty Publications
Sponsorship: US Air Force Grant FA9302-05-C-0001. A detector architecture capable of detecting both shaped offset quadrature phase shift keying (SOQPSK-TG) and Feher's quadrature phase shift keying (FQPSK-JR) is developed and analyzed. Both modulations are embodied as fully interoperable modulations in the Interrange Instrumentation Group (IRIG) standard IRIG-106. It is shown that the common detector achieves near optimal bit error rate performance without knowledge of which modulation is used by the transmitter. The detection techniques are based on a common trellis-coded modulation representation and a common continuous phase modulation (CPM) representation for these two modulations. In addition the common pulse amplitude …
The Detection Efficiency Of Artm Cpm In Aeronautical Telemetry, Michael D. Rice, Erik Perrins
The Detection Efficiency Of Artm Cpm In Aeronautical Telemetry, Michael D. Rice, Erik Perrins
Faculty Publications
ARTM CPM is a partial response, two-index continuous-phase modulation that was adopted as a standard in IRIG 106-04 for aeronautical telemetry. This waveform was selected because it achieves approximately three times the spectral efficiency of PCM/FM. However, the optimum receiver requires 128 real-valued matched filters and keeps track of the waveform state with a trellis of 512 states and 2048 branches. Various complexity reducing techniques are applied and the resulting loss in detection efficiency is quantified. It is shown that the full 512-state trellis is not required to achieve the desired detection efficiency: two different 32-state configurations were found to …
Wideband Channel Model For Aeronautical Telemetry, Christian Bettweiser, Adam Davis, Michael D. Rice
Wideband Channel Model For Aeronautical Telemetry, Christian Bettweiser, Adam Davis, Michael D. Rice
Faculty Publications
A multipath channel model for wideband aeronautical telemetry links is presented. Channel sounding data were collected at Edwards AFB, CA, at both L-band and lower S-band. Frequency domain analysis techniques were used to evaluate candidate channel models. The channel model is composed of three propagation paths: a line-of-sight direct path and two specular reflections. The first specular reflection is characterized by a relative amplitude of 70% to 96% of the line-of-sight amplitude and a delay of 10—80 ns. This path is the result of “ground bounces” off the dry lake bed at Edwards and is a typical terrain feature at …