scholarly journals Improvement of Persistent Scatterer Interferometry to Detect Large Non-Linear Displacements with the 2π Ambiguity by a Non-Parametric Approach

2019 ◽  
Vol 11 (21) ◽  
pp. 2467
Author(s):  
Ogushi ◽  
Matsuoka ◽  
Defilippi ◽  
Pasquali
Keyword(s):  
Data Processing ◽  
Observation Data ◽  
Maximum Magnitude ◽  
Parametric Approach ◽  
Persistent Scatterer Interferometry ◽  
Surface Displacements ◽  
Persistent Scatterer ◽  
Non Linear ◽  
Simulation Results ◽  
Non Parametric

Persistent scatterer interferometry (PSI) is commonly applied to monitor surface displacements with millimetric precision. However, this technique still has trouble estimating non-linear displacements because the algorithm is designed for the slow and linear displacements. Additionally, there is a variety of non-linear displacement types, and finding an appropriate displacement model for PSI is still assumed to be a fairly large task. In this paper, the conventional PSI technique is extended using a non-parametric non-linear approach (NN-PSI), and the performance of the extended method is investigated by simulations and actual observation data processing with TerraSAR-X. In the simulation, non-linear displacements are modeled by the magnitudes and periods of the displacement, and the evaluation of NN-PSI is conducted. According to the simulation results, the maximum magnitude of the displacement that can be estimated by NN-PSI is two and a half times the magnitude of the SAR sensor’s wavelength (2.5λ that is roughly equivalent to 8 cm for X-band, 14 cm for C-band, and 60 cm for L-band), and the period of the displacement is about three months. However, this displacement cannot be reconstructed by the conventional PSI due to the limitation, known as the 2π displacement ambiguity. The result of the observation data processing shows that a large displacement with the 2π ambiguity can be estimated by NN-PSI as the simulation results show, but the conventional PSI cannot reconstruct it. In addition, a different approach, Small BAseline Subset (SBAS), is applied to the same data to ensure the accuracy of results, and the correlation between NN-PSI and SBAS is 0.95, while that between the conventional PSI and SBAS is –0.66. It is concluded that NN-PSI enables the reconstruction of non-linear displacements by the non-parametric approach and the expansion of applications to measure surface displacements that could not be measured due to the limitations of the traditional PSI methods.

scholarly journals Implementation of Non-Linear Non-Parametric Persistent Scatterer Interferometry and Its Robustness for Displacement Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 1004
Author(s):  
Fumitaka Ogushi ◽  
Masashi Matsuoka ◽  
Marco Defilippi ◽  
Paolo Pasquali
Keyword(s):  
Data Processing ◽  
Surface Displacement ◽  
Real Data ◽  
Velocity Spectrum ◽  
Persistent Scatterer Interferometry ◽  
Implementation Phase ◽  
The Real ◽  
Persistent Scatterer ◽  
Non Linear ◽  
Non Parametric

To derive surface displacement, interferometric stacking with synthetic aperture radar (SAR) data is commonly used, and this technique is now in the implementation phase in the real world. Persistent scatterer interferometry (PSI) is one of the most universal approaches among in- terferometric stacking techniques, and non-linear non-parametric PSI (NN-PSI) was proposed to overcome the drawbacks of PSI approaches. The estimation of the non-linear displacements was successfully conducted using NN-PSI. However, the estimation of NN-PSI is not always stable with certain displacements because wider range of the velocity spectrum is used in NN-PSI than the conventional approaches; therefore, a calculation procedure and parameter optimization are needed to consider. In this paper, optimized parameters and procedures of NN-PSI are proposed, and real data processing with Sentinel-1 in the Kanto region in Japan was conducted. We confirmed that the displacement estimation was comparable to the measurement of the permanent global positioning system (GPS) stations, and the root mean square error between the GPS measurement and NN-PSI estimation was less than 3 mm in two years. The displacement over 2π ambiguity, which the conventional PSI approach wrongly reconstructed, was also quantitatively validated and successfully estimated by NN-PSI. As a result of the real data processing, periodical displacements were also reconstructed through NN-PSI. We concluded that the NN-PSI approach with the proposed parameters and method enabled the estimation of several types of surface displacements that conventional PSI approaches could not reconstruct.

Distributed resilient consensus: a non-parametric approach

2018 ◽  
Vol 41 (8) ◽  
pp. 2124-2134 ◽  
Author(s):  
Halil Yiğit Öksüz ◽  
Mehmet Akar
Keyword(s):  
Fault Tolerant ◽  
Consensus Problem ◽  
Parametric Approach ◽  
Detection Scheme ◽  
Consensus Algorithms ◽  
Simulation Results ◽  
Distributed Fault Detection ◽  
Initial Knowledge ◽  
Two Parameter ◽  
Non Parametric

In this paper, two parameter-independent fault-tolerant consensus algorithms are proposed to address the consensus problem in the presence of misbehaving agents. The first algorithm relies on adaptively estimating the number of faulty agents in the network by using a distributed fault-detection scheme. It is shown that this algorithm converges if the network of non-faulty agents is ( f+1)-robust, where f is the number of faulty agents in the network. The second algorithm is a non-parametric Mean-Subsequence-Reduced algorithm whose convergence is guaranteed if the network of non-faulty nodes is ( f+1)-robust and all non-faulty nodes have the same number of in-neighbours. Neither algorithm requires initial knowledge on the number of faulty agents in the network. The efficacy of the algorithms are illustrated with simulation results.

A non-parametric approach to non-linear causality testing

1996 ◽  
Vol 51 (1) ◽  
pp. 7-18 ◽  
Author(s):  
David Bell ◽  
Jim Kay ◽  
Jim Malley
Keyword(s):  
Parametric Approach ◽  
Non Linear ◽  
Causality Testing ◽  
Non Parametric

scholarly journals IW Sentinel-1 satellite scenes for the investigation of mine slope stability: experiences from the Riacho dos Machados gold mine (Brazil)

2021 ◽  
Vol 25 (1) ◽  
pp. 93-99
Author(s):  
Marcos Eduardo Hartwig ◽  
Leandro Ribes De Lima ◽  
Daniele Perissin
Keyword(s):  
Open Pit ◽  
Southeastern Brazil ◽  
Gold Mine ◽  
Persistent Scatterer Interferometry ◽  
Surface Displacements ◽  
Persistent Scatterer ◽  
Minas Gerais State ◽  
Mine Slope ◽  
Radar Satellite ◽  
Orbit Geometry

In the last decade, the Persistent Scatterer Interferometry – PSI have been largely employed to predict instabilities and failure in open pit mines. The PSI is a powerful technique, which combines radar satellite data in order to detect and monitor tiny surface displacements over vast areas. In the last years, the Sentinel-1 radar mission have produced images of the globe acquired with different spatial and temporal resolutions that are now freely available. In recent years, the footwall slopes of the Riacho dos Machados Gold Mine – MRDM (Minas Gerais state, southeastern Brazil) have recorded large planar failures controlled by foliation planes. Therefore, the focus of this paper is to evaluate a stack of 39 Interferometric Wide Sentinel-1 scenes, spanning from January 2018 to April 2019, acquired in descending orbit geometry, for the detection and monitoring of surface displacements in the MRDM. The results have shown that descending IW Sentinel-1 scenes can be used to provide a broad picture of the Line-Of-Sight - LOS deformation phenomena. In order to monitor the evolution of the deformation phenomena induced by mining activities, LOS deformation maps with millimeter accuracy could be only delivered at least each 12 days.

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