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About 9,032 papers for “Ambiguity function”

Ambiguity function for sonar

José M. F. Moura, M.J. Rendas · 2003

The authors present a new definition of ambiguity and illustrate its application to the study of passive localization of sources in deep ocean situations. The tool developed allows the study of the impact of all relevant parameters, including those relative to the physical medium as well as those pertinent to the instrumentation and signals involved. Particular attention is given to such factors as source signal bandwidth and array size and location. The potential impact of a modelization of the temporal (interarrival) structure is demonstrated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Cited by 2

Advanced ambiguity function optical processors

Peter S. Guilfoyle · 1983

This paper describes two advanced ambiguity function optical processors optimized to compute the time/frequency (ambiguity) function for wideband range Dopp1er/radars. The ambituity function will be described in both closed and triple matrix product form. Two acousto optic implementations will be discussed (1) analog hybrid time and space, and (2) binary optical systolic matrix processor. The two architectures will be compared. Results will be shown for the analog optical implementation.

Cited by 0

On the Spatial Ambiguity Function

Arthur N. Yuryev, prepared for publication by V. A. Yuryev · arXiv (Cornell University) · 2014

The ambiguity function of a spatial signal in the "signal spatial frequency displacement vs antenna linear displacement" coordinates is considered in this paper; in case of a monochromatic signal with known carrier frequency, spatial signal vector angular displacement is considered as the second coordinate. The analysis is made taking into account an external (reradiated or thermal) background which contributes considerable peculiarities in the properties of the spatial ambiguity function. Accuracy of measuring the signal linear or angular displacement and resolution are determined. Examples for the Fresnel and Fraunhofer zones are given.

Cited by 0Open access

Algorithms for ambiguity function processing

Shahar Stein · IEEE Transactions on Acoustics Speech and Signal Processing · 1981

Calculation of the complex ambiguity function is viewed as the basis for joint estimation of the differential delay and differential frequency offset between two waveforms that contain a common component plus additive noise. In many applications, the required accuracy leads to a need for integration over long data sets that can become a challenge for near real-time digital processing. The nature of the ambiguity processing is interpreted, and an algorithm approach is shown that minimizes the processing burden over a broad category of applications without affecting performance.

Cited by 486

Wideband ambiguity function of broadband signals

Zhen-biao Lin · The Journal of the Acoustical Society of America · 1988

Broadband signal analysis and design for radar and sonar systems require the use of a wideband ambiguity function (WAF) to estimate their performance. The properties of WAF for FM signals are studied and the results of numerical computation are compared with the theoretical expressions. The main findings presented here include the following. (a) A broadband LFM signal is not a Doppler tolerant one. At high velocity, the magnitude of WAF is similar to the signal envelope, and its range resolution decreases obviously. (b) an LPM signal exhibits a fairly good range resolution, even at very high velocity. The performances of Doppler tolerant signals for three models are described and compared. The different envelopes for the LPM case have little influence on the behavior of WAF. (c) The unbiased delay estimation for both LFM and LPM signals, with bandwidth B= f max− f min and duration T, can be obtained by a special shift in time, which is such that t ∈ ( f minT/B, f maxT/B). An approximate method for derivation of WAF, based on the Doppler cross-power spectrum and the stationary phase principle, is proposed. Such an analysis is applied to a bat’s sonar signal.

Cited by 64

Teager energy and the ambiguity function

Rare & Special e-Zone (The Hong Kong University of Science and Technology) · 1999

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Cited by 0

Wideband Auto-Ambiguity Function Nulling Algorithm

Nathaniel A. Henry, J.F. Doherty, David Jenkins · MILCOM 2021 - 2021 IEEE Military Communications Conference (MILCOM) · 2021

This report discusses the placement of null regions on the wideband auto-ambiguity function (WBAAF). To date, the majority of papers on this subject apply the null regions to the narrow band, side lobe cancellation of the auto-ambiguity function for a radar echo pulse. By selectively placing a null region in an original waveform&#x0027;s WBAAF, a transmit sequence, especially a white noise radar pulse, can be tailored to lower the energy of peak regions on the WBAAF surface that might be masking desirable portions. The approach discussed in this paper is a unique iterative algorithm which we have termed the Wideband Nulling Algorithm. The Wideband Nulling Algorithm operates on time-scaled data and thus inherently utilizes a wideband approach to placing a null in the ambiguity function surface. Since the algorithm operates on the time domain series, it maps an original waveform to a new time domain waveform such that its second order statistics have a WBAAF surface containing the desired null regions. The goal is to perform this mapping operation with minimal disturbance or impact to the original signal so that the signal content or message is not disturbed. This Wideband Nulling Algorithm is an elegantly simple, mathematical process to reduce interference clutter peaks from a radar, sonar, or an ultrasound ambiguity function surface. This fundamental process has potential applications to many fields including biomedical imaging.

Cited by 2