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Eshagh, Mehdi, ProfessorORCID iD iconorcid.org/0000-0003-0067-8631
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Publikationer (10 of 92) Visa alla publikationer
Eshagh, M. (2023). Optimal Configuration for Monitoring Stations in a Wireless Localisation Network Based on Received Signal Strength Differences.. Sensors, 23(3), Article ID 1150.
Öppna denna publikation i ny flik eller fönster >>Optimal Configuration for Monitoring Stations in a Wireless Localisation Network Based on Received Signal Strength Differences.
2023 (Engelska)Ingår i: Sensors, E-ISSN 1424-8220, Vol. 23, nr 3, artikel-id 1150Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

A smart city is a city equipped with many sensors communicating with each other for different purposes. Cybersecurity and signal security are important in such cities, especially for airports and harbours. Any signal interference or attack on the navigation of autonomous vehicles and aircraft may lead to catastrophes and risks in people's lives. Therefore, it is of tremendous importance to develop wireless security networks for the localisation of any radio frequency interferer in smart cities. Time of arrival, angle of arrival, time-difference of arrivals, received signal strength and received signal strength difference (RSSD) are known observables used for the localisation of a signal interferer. Localisation means to estimate the coordinates of an interferer from some established monitoring stations and sensors receiving such measurements from an interferer. The main goal of this study is to optimise the geometric configuration of the monitoring stations using a desired dilution of precision and/or variance-covariance matrix (VCM) for the transmitter's location based on the RSSD. The required mathematical models are developed and applied to the Arlanda international airport of Sweden. Our numerical tests show that the same configuration is achieved based on dilution of precision and VCM criteria when the resolution of design is lower than 20 m in the presence of the same constraints. The choice of the pathloss exponent in the mathematical models of the RSSDs is not important for such low resolutions. Finally, optimisation based on the VCM is recommended because of its larger redundancy and flexibility in selecting different desired variances and covariances for the coordinates of the transmitter.

Ort, förlag, år, upplaga, sidor
MDPI, 2023
Nyckelord
jamming, least-squares method, quadratic optimisation, spoofing, variance-covariance matrix
Nationell ämneskategori
Annan geovetenskap och miljövetenskap
Identifikatorer
urn:nbn:se:hv:diva-19669 (URN)10.3390/s23031150 (DOI)000930253000001 ()36772189 (PubMedID)2-s2.0-85147842090 (Scopus ID)
Anmärkning

CC-BY 4.0

Tillgänglig från: 2023-09-13 Skapad: 2023-09-13 Senast uppdaterad: 2024-01-12Bibliografiskt granskad
Eshagh, M. (2023). Optimization of Basepoint Configuration in Localization of Signal Interference Device. Journal of Surveying Engineering, 149(1), Article ID 1150.
Öppna denna publikation i ny flik eller fönster >>Optimization of Basepoint Configuration in Localization of Signal Interference Device
2023 (Engelska)Ingår i: Journal of Surveying Engineering, ISSN 0733-9453, E-ISSN 1943-5428, Vol. 149, nr 1, artikel-id 1150Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Precise navigation, as a method for guiding vehicles from one point to another, is an important subject these days especially in navigation of aircraft. Global navigation satellite systems (GNSSs) are capable tools for such a purpose. Any intentional or unintentional interference in satellite signals may cause risks of deadly accidents. Therefore, it is tremendously important to control airports or harbors and locate any existing radio frequency interference device. This localization can be done based on measuring time of arrival (TOA), angle of arrival (AOA), or time difference of arrival (TDOA) of signals from the device to sensors or receivers at some basepoints. In this article, a method is proposed based on these arrivals for optimizing the configuration created by these basepoints from a large grid of points covering a control area. Furthermore, a simulation test was performed to verify the theory, and after that a control network was designed and optimized for the international Landvetter Airport of Sweden. Our simulation studies show that when the AOA is used, our optimization is more robust with respect to the control grid resolution. In addition, optimization based on the TDOA improves the coverage over the control area with a significant reduction of error of control points, but because of the special geometric shape of the Landvetter Airport, such an optimization was not successful. 

Ort, förlag, år, upplaga, sidor
American Society of Civil Engineers (ASCE), 2023
Nyckelord
Air navigation; Aircraft accidents; Airport security; Communication satellites; Global positioning system; Quadratic programming; Radio interference; Radio navigation; Satellite antennas; Time difference of arrival; Aoa (angleof-arrival); Base points; Constraint; Dilution of precision; Global navigation satellite system; Global Navigation Satellite Systems; Interference devices; Localisation; Optimisations; Quadratic optimization; aircraft; airport; GNSS; optimization; precision; Airports
Nationell ämneskategori
Geofysik
Identifikatorer
urn:nbn:se:hv:diva-19502 (URN)10.1061/(ASCE)SU.1943-5428.0000416 (DOI)000899310700005 ()2-s2.0-85143601129 (Scopus ID)
Anmärkning

CC-BY 4.0

Tillgänglig från: 2023-09-13 Skapad: 2023-09-13 Senast uppdaterad: 2024-01-12Bibliografiskt granskad
Fatolazadeh, F., Eshagh, M., Goïta, K. & Wang, S. (2022). A New Spatiotemporal Estimator to Downscale GRACE Gravity Models for Terrestrial and Groundwater Storage Variations Estimation. Remote Sensing, 14(23)
Öppna denna publikation i ny flik eller fönster >>A New Spatiotemporal Estimator to Downscale GRACE Gravity Models for Terrestrial and Groundwater Storage Variations Estimation
2022 (Engelska)Ingår i: Remote Sensing, E-ISSN 2072-4292, Vol. 14, nr 23Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This study proposes a new mathematical approach to downscale monthly terrestrial water storage anomalies (TWSA) from the Gravity Recovery and Climate Experiment (GRACE) and estimates groundwater storage anomalies (GWSA) at a daily temporal resolution and a spatial resolution of 0.25° × 0.25°, simultaneously. The method combines monthly 3° GRACE gravity models and daily 0.25° hydrological model outputs and their uncertainties in the spectral domain by minimizing the mean-square error (MSE) of their estimator to enhance the quality of both low and high frequency signals in the estimated TWSA and GWSA. The Global Land Data Assimilation System (GLDAS) was the hydrological model considered in this study. The estimator was tested over Alberta, Saskatchewan, and Manitoba (Canada), especially over the Province of Alberta, using data from 65 in-situ piezometric wells for 2003. Daily minimum and maximum GWS varied from 14 mm to 32 mm across the study area. A comparison of the estimated GWSA with the corresponding in-situ wells showed significant and consistent correlations in most cases, with r = 0.43–0.92 (mean r = 0.73). Correlations were >0.70 for approximately 70% of the wells, with root mean square errors <24 mm. These results provide evidence for using the proposed spectral combination estimator in downscaling GRACE data on a daily basis at a spatial scale of 0.25° × 0.25°.  

Ort, förlag, år, upplaga, sidor
MDPI, 2022
Nyckelord
Climate models; Frequency estimation; Geodetic satellites; Groundwater; Mean square error; Uncertainty analysis; Daily spatiotemporal downscaling; Down-scaling; Gravity modeling; Gravity recovery and climate experiment satellites; Gravity recovery and climate experiments; Groundwater storage; Groundwater storage change; Spectral combination; Storage changes; Terrestrial water storage; Digital storage
Nationell ämneskategori
Klimatforskning
Identifikatorer
urn:nbn:se:hv:diva-19504 (URN)10.3390/rs14235991 (DOI)000897372500001 ()2-s2.0-85143797146 (Scopus ID)
Anmärkning

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Tillgänglig från: 2023-01-23 Skapad: 2023-01-23 Senast uppdaterad: 2024-04-12
Eshagh, M. (2022). An optimal design of GNSS interference localisation wireless security network based on time-difference of arrivals for the Arlanda international airport. Journal of Geodetic Science, 12(1), 154-164
Öppna denna publikation i ny flik eller fönster >>An optimal design of GNSS interference localisation wireless security network based on time-difference of arrivals for the Arlanda international airport
2022 (Engelska)Ingår i: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 12, nr 1, s. 154-164Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Today, most of the aircrafts are navigated by global navigation satellite systems (GNSSs). Landing is a dangerous phase of a flight especially when an airport runway is not clearly seen from the aircrafts. In such cases, GNSSs are useful for a safe landing under the circumstances that healthy signals, free of any interference, reach to GNSSs receiver antennas mounted on the aircrafts. This shows the importance of establishing GNSS interference localisation security networks around airports. Designing a good configuration for the points with GNSS antennas at for receiving interference signals is important for a successful localisation of the interference device. Here, the time-difference of the arrivals of an interference signal to such points or anchor nodes (ANs), are used as observables, and a security network with four ANs is optimally designed along the runways of the Arlanda airport to reduce the dilution of precision (DOP) of the network. Our study showed that by such an optimisation, the maximum DOP value can reduce by 50% meaning a significant increase in the probability of a successful interference device localisation.

Ort, förlag, år, upplaga, sidor
De Gruyter Open, 2022
Nyckelord
Jamming; signal interference; spoofing; quadratic optimisation; directional constraints; dilution of precession
Nationell ämneskategori
Geofysik
Identifikatorer
urn:nbn:se:hv:diva-19426 (URN)10.1515/jogs-2022-0142 (DOI)000879998900001 ()2-s2.0-85142169981 (Scopus ID)
Anmärkning

CC-BY 4.0

Tillgänglig från: 2023-01-09 Skapad: 2023-01-09 Senast uppdaterad: 2023-01-09
Eshagh, M. (2022). Analysis of the gravity field, direct and inverse problems [Review]. Journal of Geodetic Science, 12(1), 244-245
Öppna denna publikation i ny flik eller fönster >>Analysis of the gravity field, direct and inverse problems
2022 (Engelska)Ingår i: Journal of Geodetic Science, ISSN 2081-9919, E-ISSN 2081-9943, Vol. 12, nr 1, s. 244-245Artikel, recension (Refereegranskat) Published
Abstract [en]

This new book deals with, as its titles says, the analysis and process of gravity field of the Earth. The book is mathematically oriented, and the authors have explained how Mathematics is used for local analysis of the gravity field. The basic and required background knowledge, needed for understanding the book, are given in early chapters as well as appendices. They are used for explaining gravity field analysis from measurement surveys, corrections, and processes to direct and inverse problems in exploration Geophysics with interesting exercises, numerical and real examples.

Ort, förlag, år, upplaga, sidor
De Gruyter Open, 2022
Nyckelord
Gravity fields, book review
Nationell ämneskategori
Geofysik
Identifikatorer
urn:nbn:se:hv:diva-19840 (URN)10.1515/jogs-2022-0149 (DOI)000925121100001 ()
Tillgänglig från: 2023-11-08 Skapad: 2023-11-08 Senast uppdaterad: 2023-11-08
Scotti, A., Batista, M. A. & Eshagh, M. (2022). Inaccuracy in arc power calculation through a product of voltage and current averages. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 44(1), 1-9, Article ID 11.
Öppna denna publikation i ny flik eller fönster >>Inaccuracy in arc power calculation through a product of voltage and current averages
2022 (Engelska)Ingår i: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 44, nr 1, s. 1-9, artikel-id 11Artikel i tidskrift (Övrigt vetenskapligt) Published
Abstract [en]

Power is an indirect measurand, determined by processing voltage and current analogue signals through calculations. Using arc welding as a case study, the objective of this work was to bring up subsidies for power calculation. Based on the defnitions of correlation and covariance in statistics, a mathematical demonstration was developed to point out the diference between the product of two averages (e.g. P=UxI) and the average of the products (e.g. P=(UxI). Complementarily, a brief on U and I waveform distortion sources were discussed, emphasising the diference between signal standard deviations and measurement errors. It was demonstrated that the product of two averages is not the same as the average of the products, unless in specifc conditions (when the variables are fully correlated). It was concluded that the statistical correlation can easily fag the interrelation, but if assisted by covariance, these statistics quantify the inaccuracy between approaches. Finally, although the statistics' determination is easy to implement, it is proposed that power should always be calculated as the average of the instantaneous U and I products. It is also proposed that measurement error sources should be observed and mitigated, since they predictably interfere in power calculation accuracy.

Ort, förlag, år, upplaga, sidor
Brazilian Society of Mechanical Sciences and Engin, 2022
Nyckelord
Electrical power measurement, Arc welding, Instantaneous power, Probability theory, Covariance, Correlation
Nationell ämneskategori
Bearbetnings-, yt- och fogningsteknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-17966 (URN)10.1007/s40430-021-03317-6 (DOI)000728176000002 ()2-s2.0-85120972487 (Scopus ID)
Anmärkning

Creative Commons Attribution 4.0 International License

Tillgänglig från: 2021-12-23 Skapad: 2021-12-23 Senast uppdaterad: 2024-04-12Bibliografiskt granskad
Fatolazadeh, F., Eshagh, M. & Goïta, K. (2022). New spectro-spatial downscaling approach for terrestrial and groundwater storage variations estimated by GRACE models. Journal of Hydrology, 615(Part A), Article ID 128635.
Öppna denna publikation i ny flik eller fönster >>New spectro-spatial downscaling approach for terrestrial and groundwater storage variations estimated by GRACE models
2022 (Engelska)Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 615, nr Part A, artikel-id 128635Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The study proposes a new mathematical method, referred to as spectral combination, to downscale Gravity Recovery And Climate Experiment (GRACE) observations. The goal is to improve the spatial resolution of GRACE from 1̊ to 0.25̊, based upon available hydrological variables. First, a new approach based upon condition adjustment is proposed to estimate uncertainties related to hydrological variables. Second, a spectral-spatial estimator is developed to derive downscaled Total Water Storage Anomalies (TWSA) by optimally combining GRACE models and hydrological variables. Last, groundwater storage anomalies (GWSA) are derived from the downscaled TWSA. The proposed spectral combination approach was tested over the Canadian Prairies by considering GRACE data and required Global Land Data Assimilation System (GLDAS) variables for February 2003 to December 2016. The results reveal greater details in TWSA after spatial downscaling. Quantitatively, retrieved downscaled GWSA were validated using 75 unconfined in situ piezometric wells that were distributed across the Province of Alberta. A correlation of 0.80, with an RMSE of 11 mm, was obtained after downscaling with all wells over the validation area. These results are better than those obtained before downscaling (correlation of 0.42, with an RMSE of 21.4 mm), demonstrating that the proposed approach is successful. 

Ort, förlag, år, upplaga, sidor
Elsevier, 2022
Nyckelord
Estimation; Geodetic satellites; Groundwater; Uncertainty analysis; Water conservation; Down-scaling; Experiment modeling; Gravity recovery and climate experiment satellites; Gravity recovery and climate experiments; Groundwater storage; Groundwater storage variation; Hydrological variables; Spatial downscaling; Spectral combination; Water storage; Digital storage
Nationell ämneskategori
Geofysik Oceanografi, hydrologi och vattenresurser
Identifikatorer
urn:nbn:se:hv:diva-19434 (URN)10.1016/j.jhydrol.2022.128635 (DOI)000913192900004 ()2-s2.0-85142155053 (Scopus ID)
Anmärkning

This study was funded by the Université de Sherbrooke (Excellence Scholarship Program), and the Natural Sciences and Engineering Research Council of Canada (NSERC Discovery Grant Number: RGPIN-2018- 06101; NSERC Create Grant: 543360-2020). We thank all data and products providers, University of Texas at Austin, Natural Resources Canada, and the Goddard Earth Sciences Data and Information Services Center. We gratefully thank for all valuable suggestions from two reviewers, and JOH editorial team, which help us improve the manuscript significantly. We thank W.F.J. Parsons for correcting the English.

CC-BY 4.0

Tillgänglig från: 2023-01-23 Skapad: 2023-01-23 Senast uppdaterad: 2024-04-12
Meghraoui, M., Sundararajan, N., Banerjee, S., Hinzen, K.-G., Eshagh, M., Roure, F., . . . Michard, A. (2022). Preface. In: Meghraoui M., Sundararajan N., Banerjee S., Hinzen Klaus-G., Eshagh M., Roure F., Chaminé H.I., Maouche S., Michard A. (Ed.), Advances in Science, Technology and Innovation: 2nd Springer Conference of the Arabian Journal of Geosciences, CAJG-2 2019 Sousse25 November 2019 through 28 November 2019. Springer Nature
Öppna denna publikation i ny flik eller fönster >>Preface
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2022 (Engelska)Ingår i: Advances in Science, Technology and Innovation: 2nd Springer Conference of the Arabian Journal of Geosciences, CAJG-2 2019 Sousse25 November 2019 through 28 November 2019 / [ed] Meghraoui M., Sundararajan N., Banerjee S., Hinzen Klaus-G., Eshagh M., Roure F., Chaminé H.I., Maouche S., Michard A., Springer Nature, 2022Kapitel i bok, del av antologi (Övrigt vetenskapligt)
Ort, förlag, år, upplaga, sidor
Springer Nature, 2022
Serie
Advances in Science, Technology and Innovation, ISSN 2522-8714
Nyckelord
Geosciences
Nationell ämneskategori
Geofysik
Identifikatorer
urn:nbn:se:hv:diva-18394 (URN)2-s2.0-85128877049 (Scopus ID)9783030730253 (ISBN)
Tillgänglig från: 2022-09-19 Skapad: 2022-09-19 Senast uppdaterad: 2022-09-22Bibliografiskt granskad
Mahbuby, H., Amerian, Y., Nikoofard, A. & Eshagh, M. (2021). Application of the nonlinear optimisation in regional gravity field modelling using spherical radial base functions. Studia Geophysica et Geodaetica, 65(3-4), 261-290
Öppna denna publikation i ny flik eller fönster >>Application of the nonlinear optimisation in regional gravity field modelling using spherical radial base functions
2021 (Engelska)Ingår i: Studia Geophysica et Geodaetica, ISSN 0039-3169, E-ISSN 1573-1626, Vol. 65, nr 3-4, s. 261-290Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The gravity field is a signature of the mass distribution and interior structure of the Earth, in addition to all its geodetic applications especially geoid determination and vertical datum unification. Determination of a regional gravity field model is an important subject and needs to be investigated and developed. Here, the spherical radial basis functions (SBFs) are applied in two scenarios for this purpose: interpolating the gravity anomalies and solving the fundamental equation of physical geodesy for geoid or disturbing potential determination, which has the possibility of being verified by the Global Navigation Satellite Systems (GNSS)/levelling data. Proper selections of the number of SBFs and optimal location of the applied SBFs are important factors to increase the accuracy of estimation. In this study, the gravity anomaly interpolation based on the SBFs is performed by Gauss-Newton optimisation with truncated singular value decomposition, and a Quasi-Newton method based on line search to solve the minimisation problems with a small number of iterations is developed. In order to solve the fundamental equation of physical geodesy by the SBFs, the truncated Newton optimisation is applied as the Hessian matrix of the objective function is not always positive definite. These two scenarios are applied on the terrestrial free-air gravity anomalies over the topographically rough area of Auvergne. The obtained accuracy for the interpolated gravity anomaly model is 1.7 mGal with the number of point-masses about 30% of the number of observations, and 1.5 mGal in the second scenario where the number of used kernels is also 30%. These accuracies are root mean square errors (RMSE) of the differences between predicted and observed gravity anomalies at check points. Moreover, utilising the optimal constructed model from the second scenario, the RMSE of 9 cm is achieved for the differences between the gravimetric height anomalies derived from the model and the geometric height anomalies from GNSS/levelling points. © 2021, The Authors.

Ort, förlag, år, upplaga, sidor
Springer Science and Business Media B.V., 2021
Nyckelord
spherical radial basis functions, SBFs, geodesy, gravity, nonlienar optimisation
Nationell ämneskategori
Geofysik Övrig annan teknik
Forskningsämne
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-17977 (URN)10.1007/s11200-020-1077-y (DOI)000729372200001 ()2-s2.0-85121027600 (Scopus ID)
Tillgänglig från: 2021-12-30 Skapad: 2021-12-30 Senast uppdaterad: 2022-03-31
Rathnayake, S., Tenzer, R., Chen, W., Eshagh, M. & Pitonak, M. (2021). Comparison of Different Methods for a Moho Modeling Under Oceans and Marginal Seas: A Case Study for the Indian Ocean. Surveys in geophysics, 42(4), 839-897
Öppna denna publikation i ny flik eller fönster >>Comparison of Different Methods for a Moho Modeling Under Oceans and Marginal Seas: A Case Study for the Indian Ocean
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2021 (Engelska)Ingår i: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 42, nr 4, s. 839-897Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Since marine seismic studies are relatively sparse and unevenly distributed, detailed tomographic images of the Moho geometry under large parts of the world’s oceans and marginal seas are not yet available. Marine gravity data is, therefore, often used to detect the Moho depth in these regions. Alternatively, Airy’s isostatic theory can be applied for this purpose. In this study, we compare different isostatic and gravimetric methods for a Moho recovery under the oceanic crust and continental margins, particularly focusing on a numerical performance of Airy, Vening Meinesz-Moritz (VMM), direct gravity inversion, and generalized (for the Earth’s spherical approximation) Parker-Oldenburg methods. Numerical experiments are conducted to estimate the Moho depth beneath the Indian Ocean. Results reveal that, among these investigated methods, the VMM model is probably the most suitable for a gravimetric Moho recovery beneath the oceanic crust and continental margins, when taking into consideration the lithospheric mantle density information. This method could to some extent model realistically a Moho geometry beneath mid-oceanic spreading ridges, oceanic subductions, most of oceanic volcanic formations, and marine sediment deposits. Nonetheless, this model still cannot fully reproduce a gradual Moho deepening caused by a conductive cooling and a subsequent isostatic rebalance of the oceanic lithosphere, which can functionally be described by a Moho deepening with the increasing ocean-floor age. Results also indicate that the Airy method typically overestimates the Moho depth under oceanic volcanic formations, while the direct gravity inversion and generalized Parker-Oldenburg methods could not reproduce more detailed features in the Moho geometry. Since Pratt’s theory better describes a large-scale isostatic mechanism of the oceanic lithosphere by means of compensation density variations, but does not account for additional changes in compensation depth (i.e., Moho depth) that are caused by these density changes, we tested a possibility of combining Pratt and Airy’s isostatic theories in order to estimate the Moho depth under the oceanic crust. Even this combined model cannot fully reproduce a gradual Moho deepening with the increasing ocean-floor age.

Ort, förlag, år, upplaga, sidor
Springer Nature, 2021
Nyckelord
Continental margins; Isostasy; Oceanic crust; Gravity; Moho depth; Indian Ocean
Nationell ämneskategori
Geofysik
Identifikatorer
urn:nbn:se:hv:diva-17207 (URN)10.1007/s10712-021-09648-2 (DOI)000664000900001 ()2-s2.0-85111378692 (Scopus ID)
Tillgänglig från: 2021-12-22 Skapad: 2021-12-22 Senast uppdaterad: 2021-12-27Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-0067-8631

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