scholarly journals Methods for broadband signals mutual time delays estimating enhancement

2019 ◽  
Vol 30 ◽  
pp. 03012
Author(s):  
Ilya Grin ◽  
Oleg Morozov
Keyword(s):  
Time Delay ◽  
Computational Efficiency ◽  
Radiation Source ◽  
Time Delays ◽  
Time Delay Estimation ◽  
Ambiguity Function ◽  
Delay Estimation ◽  
Reliability Criterion ◽  
Optimal Processing ◽  
Narrowband Channels

This paper considers methods for estimating the mutual time delay of broadband signals recorded by satellites based multi-position systems for determining the location of a radiation source. All methods considered are based on modified algorithms for calculating the ambiguity function. The presented algorithms are based on the extraction of narrowband channels from the studied signals and their further optimal processing. The reliability criterion for mutual time delay estimation by the presented methods was evaluated. Based on the results and analysis of computational efficiency, viability of methods considered and their modifications was determined.

Root-Cause Analysis Based on Time Delay Estimation for Alarm Systems in Power Grids

2011 ◽  
Vol 354-355 ◽  
pp. 943-946
Author(s):  
Yi Shu Zhao ◽  
Xi Nong Li ◽  
Ke Jun Li
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Estimation Method ◽  
Root Cause Analysis ◽  
Time Delay Estimation ◽  
Power Grids ◽  
Delay Estimation ◽  
Consistency Check ◽  
Cause Analysis ◽  
Root Cause

This paper studies the root-cause analysis based on the time delays among various signals, for reducing nuisance alarms in modern industrial systems including power grids. Time delays are estimated via the revised nearest neighbor imputation method, and are validated via the subsequent consistency check. Numerical examples including the IEEE 5-node system as a prototype power grid are provided to demonstrate the effectiveness of the proposed time delay estimation method and the subsequent consistency check.

scholarly journals Detection of Direction-Of-Arrival in Time Domain Using Compressive Time Delay Estimation with Single and Multiple Measurements

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5431
Author(s):  
Youngmin Choo ◽  
Yongsung Park ◽  
Woojae Seong
Keyword(s):  
Time Delay ◽  
Time Domain ◽  
Time Delays ◽  
Matched Filter ◽  
Measurement Data ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Multiple Measurements

The compressive time delay estimation (TDE) is combined with delay-and-sum beamforming to obtain direction-of-arrival (DOA) estimates in the time domain. Generally, the matched filter that detects the arrivals at the hydrophone is used with beamforming. However, when the ocean noise smears the arrivals, ambiguities appear in the beamforming results, degrading the DOA estimation. In this work, compressive sensing (CS) is applied to accurately evaluate the arrivals by suppressing the noise, which enables the correct detection of arrivals. For this purpose, CS is used in two steps. First, the candidate time delays for the actual arrivals are calculated in the continuous time domain using a grid-free CS. Then, the dominant arrivals constituting the received signal are selected by a conventional CS using the time delays in the discrete time domain. Basically, the compressive TDE is used with a single measurement. To further reduce the noise, common arrivals over multiple measurements, which are obtained using the extended compressive TDE, are exploited. The delay-and-sum beamforming technique using refined arrival estimates provides more pronounced DOAs. The proposed scheme is applied to shallow-water acoustic variability experiment 15 (SAVEX15) measurement data to demonstrate its validity.

Parameter identification of nonlinear multirate time-delay system with uncertain output delays

2017 ◽  
Vol 40 (12) ◽  
pp. 3498-3506 ◽  
Author(s):  
Xianqiang Yang ◽  
Weili Xiong ◽  
Zeyuan Wang ◽  
Xin Liu
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Finite Impulse Response ◽  
Delay System ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Model Parameters ◽  
Delay Model ◽  
Process Data ◽  
Time Delay System

The joint parameter and time-delay estimation problems for a class of nonlinear multirate time-delay system with uncertain output delays are addressed in this paper. The practical process typically has time-delay properties and the process data are often multirate, sampled with output data inevitably corrupted by uncertain delays. The linear parameter varying (LPV) finite impulse response (FIR) multirate time-delay model is initially built to describe the considered system. The problems of over-parameterization and the existence of both continuous model parameters and discrete time-delays have made the conventional maximum likelihood difficult to solve the considered problems. In order to handle these problems, the joint parameter and time-delay estimation for the LPV FIR multirate time-delay model are formulated in the expectation-maximization scheme, and the algorithm to estimate the model parameters and time-delays is derived, simultaneously based on multirate process data. The efficacy of the proposed method is verified through a numerical simulation and a practical chemical plant.

scholarly journals A Novel Adaptive Super-Twisting Sliding Mode Control Scheme with Time-Delay Estimation for a Single Ducted-Fan Unmanned Aerial Vehicle

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 54
Author(s):  
Minh-Thien Tran ◽  
Dong-Hun Lee ◽  
Soumayya Chakir ◽  
Young-Bok Kim
Keyword(s):  
Time Delay ◽  
Sliding Mode Control ◽  
Unmanned Aerial Vehicle ◽  
Sliding Mode ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Mode Control ◽  
Ducted Fan ◽  
Control Scheme ◽  
Aerial Vehicle

This article proposes a novel adaptive super-twisting sliding mode control scheme with a time-delay estimation technique (ASTSMC-TDE) to control the yaw angle of a single ducted-fan unmanned aerial vehicle system. Such systems are highly nonlinear; hence, the proposed control scheme is a combination of several control schemes; super-twisting sliding mode, TDE technique to estimate the nonlinear factors of the system, and an adaptive sliding mode. The tracking error of the ASTSMC-TDE is guaranteed to be uniformly ultimately bounded using Lyapunov stability theory. Moreover, to enhance the versatility and the practical feasibility of the proposed control scheme, a comparison study between the proposed controller and a proportional-integral-derivative controller (PID) is conducted. The comparison is achieved through two different scenarios: a normal mode and an abnormal mode. Simulation and experimental tests are carried out to provide an in-depth investigation of the performance of the proposed ASTSMC-TDE control system.

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