Network based sensor localization in multi-media application of precision agriculture Part 2: Time of arrival

2014 ◽  
Author(s):  
Herman Sahota ◽  
Ratnesh Kumar
Keyword(s):  
Precision Agriculture ◽  
Time Of Arrival ◽  
Sensor Localization ◽  
Multi Media

scholarly journals Sensor Localization Using Time of Arrival Measurements in a Multi-Media and Multi-Path Application of In-Situ Wireless Soil Sensing

Inventions ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 16
Author(s):  
Herman Sahota ◽  
Ratnesh Kumar
Keyword(s):  
Joint Distribution ◽  
Sensor Nodes ◽  
Maximum Likelihood Estimates ◽  
Wireless Sensor ◽  
Time Of Arrival ◽  
Sensor Localization ◽  
Soil Complex ◽  
Anchor Nodes ◽  
Multi Media

The problem of localization of nodes of a wireless sensor network placed in different physical media (anchor nodes above ground and sensor nodes underground) is addressed in this article. We use time of arrival of signals transmitted between neighboring sensor nodes and between satellite nodes and sensor nodes as the ranging measurement. The localization problem is formulated as a parameter estimation of the joint distribution of the time of arrival values. The probability distribution of the time of arrival of a signal is derived based on rigorous statistical analysis and its parameters are expressed in terms of the location coordinates of the sensor nodes. Maximum likelihood estimates of the nodes’ location coordinates as parameters of the joint distribution of the various time of arrival variables in the network are computed. Sensitivity analysis to study the variation in the estimates with respect to error in measured soil complex permittivity and magnetic permeability is presented to validate the model and methodology.

Design of wireless multi-media sensor network for precision agriculture

2013 ◽  
Vol 10 (2) ◽  
pp. 71-88 ◽  
Author(s):  
Yin Shouyi ◽  
Liu Leibo ◽  
Zhou Renyan ◽  
Sun Zhongfu ◽  
Wei Shaojun
Keyword(s):  
Sensor Network ◽  
Precision Agriculture ◽  
Multi Media

scholarly journals A two-phase ranging algorithm for sensor localization in structural health monitoring

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668596 ◽  
Author(s):  
Chunfeng Wan ◽  
Lei Zhao ◽  
Youliang Ding ◽  
Songtao Xue
Keyword(s):  
Structural Integrity ◽  
Integer Ambiguity ◽  
Time Of Arrival ◽  
Sensor Localization ◽  
Two Phase ◽  
Dense Networks ◽  
Large Structures ◽  
Large Numbers ◽  
Localization Systems

Information about the positions of the sensors in sensor networks is very important, and the deployment of more and more sensors is increasing the need for automatic sensor localization. This article therefore describes a novel two-phase ranging algorithm that first obtains rough estimate of the distance to a sensor’s position using time difference of arrival or time of arrival methods and then obtains a high-resolution estimate based on the rough one using a phase-based ranging scheme. This algorithm can easily resolve the otherwise intractable integer ambiguity that often appears in localization systems, and experimental results show that it can greatly decrease the ranging error in a decentralized distance-based localization system having transmitter beacons and receivers in the nodes. Related problems such as signal filtering and multipath effect are also discussed. This algorithm can make the deployment of large numbers of sensors very simple and the determination of their positions so accurate that it would be feasible to use dense networks of sensors to monitor the structural integrity of large structures.

Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element

2020 ◽  
Vol 64 (1-4) ◽  
pp. 621-629
Author(s):  
Yingsong Zhao ◽  
Cherdpong Jomdecha ◽  
Shejuan Xie ◽  
Zhenmao Chen ◽  
Pan Qi ◽  
...  
Keyword(s):  
Coefficient Matrix ◽  
Crack Edge ◽  
Numerical Accuracy ◽  
Gauss Point ◽  
Current Testing ◽  
Efficient Simulation ◽  
Shaped Crack ◽  
Multi Media ◽  
Profile Reconstruction ◽  
Crack Profile

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.

Sign in / Sign up

Export Citation Format

Share Document