42,221 research outputs found
The Fundamentals of Radar with Applications to Autonomous Vehicles
Radar systems can be extremely useful for applications in autonomous vehicles. This paper seeks to show how radar systems function and how they can apply to improve autonomous vehicles. First, the basics of radar systems are presented to introduce the basic terminology involved with radar. Then, the topic of phased arrays is presented because of their application to autonomous vehicles. The topic of digital signal processing is also discussed because of its importance for all modern radar systems. Finally, examples of radar systems based on the presented knowledge are discussed to illustrate the effectiveness of radar systems in autonomous vehicles
Johnson(-like)-Noise-Kirchhoff-Loop Based Secure Classical Communicator Characteristics, for Ranges of Two to Two Thousand Kilometers, via Model-Line
A pair of Kirchhoff-Loop-Johnson(-like)-Noise communicators, which is able to
work over variable ranges, was designed and built. Tests have been carried out
on a model-line performance characteristics were obtained for ranges beyond the
ranges of any known direct quantum communication channel and they indicate
unrivalled signal fidelity and security performance of the exchanged raw key
bits. This simple device has single-wire secure key generation and sharing
rates of 0.1, 1, 10, and 100 bit/second for corresponding copper wire
diameters/ranges of 21 mm / 2000 km, 7 mm / 200 km, 2.3 mm / 20 km, and 0.7 mm
/ 2 km, respectively and it performs with 0.02% raw-bit error rate (99.98 %
fidelity). The raw-bit security of this practical system significantly
outperforms raw-bit quantum security. Current injection breaking tests show
zero bit eavesdropping ability without triggering the alarm signal, therefore
no multiple measurements are needed to build an error statistics to detect the
eavesdropping as in quantum communication. Wire resistance based breaking tests
of Bergou-Scheuer-Yariv type give an upper limit of eavesdropped raw bit ratio
of 0.19 % and this limit is inversely proportional to the sixth power of cable
diameter. Hao's breaking method yields zero (below measurement resolution)
eavesdropping information.Comment: Featured in New Scientist, Jason Palmer, May 23, 2007.
http://www.ece.tamu.edu/%7Enoise/news_files/KLJN_New_Scientist.pdf
Corresponding Plenary Talk at the 4th International Symposium on Fluctuation
and Noise, Florence, Italy (May 23, 2007
Bibliography and summary of methods related to the error analysis of hybrid computers technical note no. 4
Bibliography and summary of methods used in error analysis of hybrid computer
Model-Based Calibration of Filter Imperfections in the Random Demodulator for Compressive Sensing
The random demodulator is a recent compressive sensing architecture providing
efficient sub-Nyquist sampling of sparse band-limited signals. The compressive
sensing paradigm requires an accurate model of the analog front-end to enable
correct signal reconstruction in the digital domain. In practice, hardware
devices such as filters deviate from their desired design behavior due to
component variations. Existing reconstruction algorithms are sensitive to such
deviations, which fall into the more general category of measurement matrix
perturbations. This paper proposes a model-based technique that aims to
calibrate filter model mismatches to facilitate improved signal reconstruction
quality. The mismatch is considered to be an additive error in the discretized
impulse response. We identify the error by sampling a known calibrating signal,
enabling least-squares estimation of the impulse response error. The error
estimate and the known system model are used to calibrate the measurement
matrix. Numerical analysis demonstrates the effectiveness of the calibration
method even for highly deviating low-pass filter responses. The proposed method
performance is also compared to a state of the art method based on discrete
Fourier transform trigonometric interpolation.Comment: 10 pages, 8 figures, submitted to IEEE Transactions on Signal
Processin
Communication Subsystems for Emerging Wireless Technologies
The paper describes a multi-disciplinary design of modern communication systems. The design starts with the analysis of a system in order to define requirements on its individual components. The design exploits proper models of communication channels to adapt the systems to expected transmission conditions. Input filtering of signals both in the frequency domain and in the spatial domain is ensured by a properly designed antenna. Further signal processing (amplification and further filtering) is done by electronics circuits. Finally, signal processing techniques are applied to yield information about current properties of frequency spectrum and to distribute the transmission over free subcarrier channels
Cross-coupled doa trackers
A new robust, low complexity algorithm for multiuser tracking is proposed, modifying the two-stage parallel architecture of the estimate-maximize (EM) algorithm. The algorithm copes with spatially colored noise, large differences in source powers, multipath, and crossing trajectories. Following a discussion on stability, the simulations demonstrate an asymptotic and tracking behavior that neither the EM nor a nonparallelized tracker can emulate.Peer ReviewedPostprint (published version
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