Robust Resolution of Velocity Ambiguity for Multifrequency Pulse-to-Pulse Coherent Doppler Sonars

Chi, Cheng; Vishnu, Hari; Beng, Koay Teong

doi:10.1109/joe.2019.2925919

Cited by 10 publications

(8 citation statements)

References 34 publications

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“…x n (t) = A cos(ω c t + ϕ n )w n (t) (9) where A is the signal amplitude, ϕ n is the initial carrier phase of the nth symbol, w n (t) = u(t − nT c ) − u(t − nT c − T c ) is the time window function, T c is the chip width, and u(t) is the unit step function. Equations ( 8) and ( 9) can be substituted into Equation (3) in order to obtain the expression of the broadband echo signal:…”

Section: Broadband Casementioning

confidence: 99%

“…The incoherent method is suitable for applications where the detection range and velocity measurement range are large, while high stratification and velocity measurement accuracy are not required. The coherent method has high range and velocity resolution, but has the shortcoming of range-velocity ambiguity [8,9]; it is suitable for shallow water applications with thin layer thickness, where high velocity measurement accuracy is required. The broadband method combines the advantages of the incoherent and coherent methods, while its range and velocity resolution no longer restrict one another [10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved Velocity Estimation Method for Doppler Sonar Based on Accuracy Evaluation and Selection

Yang

Fang

2021

JMSE

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The matched filtering method and the waveform-tracking method cannot maintain optimal velocity estimation performance all of the time. In order to solve this problem, this paper proposes an improved velocity estimation method for Doppler sonar, based on accuracy evaluation and selection. The echo of Doppler sonar is divided into several segments with the same width as the transmitted pulse, and each segment is regarded as the echo of the corresponding water layer. According to our study’s results, the velocity estimation accuracy of each segment is positively correlated with the ratio of its autocorrelation modulus to its power. Based on this conclusion, a velocity accuracy criterion with high accuracy and low complexity is designed in order to select the optimal velocity estimation for water layers or bottoms. The proposed accuracy selection method flexibly selects the echo interval to be processed according to the accuracy criterion, so as to maintain the optimal estimation of the current’s or bottom’s velocity. Water tank and field experiments using a prototype Doppler sonar device demonstrates that, compared with the matched filtering method and the waveform-tracking method, the average velocity estimation accuracy and bias of the proposed method are superior.

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Section: Broadband Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Velocity Estimation Method for Doppler Sonar Based on Accuracy Evaluation and Selection

Yang

Fang

2021

JMSE

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show abstract

“…Since the range of χ r (t, f ) on the t-axis is |t| ≤ τ, χ r (t, f ) with different delays in Equation ( 11) will not be aliased, and the ambiguity function |χ r (t, f )| is equal to the sum of the amplitudes of all the summation terms in Equation (11). Equation (11) shows that the ambiguity function of the phase-encoded signal is superimposed by rectangular pulse ambiguity functions with different delays after amplitude weighting, and the weighting coefficient is related to the autocorrelation characteristics of the encoding. The distance and speed resolution performance of |χ r (t, f )| is mainly determined by its main peak.…”

Section: Relationship Between Velocity Estimation Accuracy and Waveform Parametersmentioning

confidence: 99%

“…The measurement methods used in ADCP include pulse incoherent method [ 8 ], pulse coherent method [ 9 , 10 , 11 ] and broadband method [ 12 , 13 , 14 ]. Since the broadband method combines the advantages of the incoherent method and the coherent method, it has become the most popular choice.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Optimization Method for Broadband ADCP Waveform with Environment Constraints

Yang

Fang

2021

Sensors

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Broadband acoustic Doppler current profiler (ADCP) is widely used in agricultural water resource explorations, such as river discharge monitoring and flood warning. Improving the velocity estimation accuracy of broadband ADCP by adjusting the waveform parameters of a phase-encoded signal will reduce the velocity measurement range and water stratification accuracy, while the promotion of stratification accuracy will degrade the velocity estimation accuracy. In order to minimize the impact of these two problems on the measurement results, the ADCP waveform optimization problem that satisfies the environment constraints while keeping high velocity estimation accuracy or stratification accuracy is studied. Firstly, the relationship between velocity or distance estimation accuracy and signal waveform parameters is studied by using an ambiguity function. Secondly, the constraints of current velocity range, velocity distribution and other environmental characteristics on the waveform parameters are studied. For two common measurement applications, two dynamic configuration methods of waveform parameters with environmental adaptability and optimal velocity estimation accuracy or stratification accuracy are proposed based on the nonlinear programming principle. Experimental results show that compared with the existing methods, the velocity estimation accuracy of the proposed method is improved by more than 50%, and the stratification accuracy is improved by more than 22%.

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“…The robust CRT claims that even though every remainder has a small error, a large nonnegative integer can be robustly reconstructed in the sense that the reconstruction error is upper bounded by the bound of the remainder errors. Beyond these applications aforementioned, the robust CRT has offered useful applications in multi-wavelength optical measurement [25]- [27], distance or velocity ambiguity resolution [28]- [31], fault-tolerant wireless sensor networks [32]- [34], error-control neural coding [35]- [37], etc. It is worth pointing out that the (robust) CRT has been generalized to (robustly) reconstruct multiple large nonnegative integers from their unordered remainder sets as well [38]- [44].…”

Section: Introductionmentioning

confidence: 99%

Exact and Robust Reconstructions of Integer Vectors Based on Multidimensional Chinese Remainder Theorem (MD-CRT)

Xiao,

Xia,

Wang

2020

Preprint

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The robust Chinese remainder theorem (CRT) has been recently proposed for robustly reconstructing a large nonnegative integer from erroneous remainders. It has found many applications in signal processing, including phase unwrapping and frequency estimation under sub-Nyquist sampling. Motivated by the applications in multidimensional (MD) signal processing, in this paper we propose the MD-CRT and robust MD-CRT for integer vectors. Specifically, by rephrasing the abstract CRT for rings in number-theoretic terms, we first derive the MD-CRT for integer vectors with respect to a general set of integer matrix moduli, which provides an algorithm to uniquely reconstruct an integer vector from its remainders, if it is in the fundamental parallelepiped of the lattice generated by a least common right multiple of all the moduli. For some special forms of moduli, we present explicit reconstruction formulae. Moreover, we derive the robust MD-CRT for integer vectors when the remaining integer matrices of all the moduli left divided by their greatest common left divisor (gcld) are pairwise commutative and coprime. Two different reconstruction algorithms are proposed, and accordingly, two different conditions on the remainder error bound for the reconstruction robustness are obtained, which are related to a quarter of the minimum distance of the lattice generated by the gcld of all the moduli or the Smith normal form of the gcld.

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Robust Resolution of Velocity Ambiguity for Multifrequency Pulse-to-Pulse Coherent Doppler Sonars

Cited by 10 publications

References 34 publications

Improved Velocity Estimation Method for Doppler Sonar Based on Accuracy Evaluation and Selection

Improved Velocity Estimation Method for Doppler Sonar Based on Accuracy Evaluation and Selection

Dynamic Optimization Method for Broadband ADCP Waveform with Environment Constraints

Exact and Robust Reconstructions of Integer Vectors Based on Multidimensional Chinese Remainder Theorem (MD-CRT)

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