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Bagherbandi, Mohammad, ProfessorORCID iD iconorcid.org/0000-0003-0910-0596
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Publications (10 of 87) Show all publications
Dashtbazi, A., Voosoghi, B., Bagherbandi, M. & Tenzer, R. (2023). A High-Resolution Global Moho Model from Combining Gravimetric and Seismic Data by Using Spectral Combination Methods. Remote Sensing, 15(6), Article ID 1562.
Open this publication in new window or tab >>A High-Resolution Global Moho Model from Combining Gravimetric and Seismic Data by Using Spectral Combination Methods
2023 (English)In: Remote Sensing, E-ISSN 2072-4292, Vol. 15, no 6, article id 1562Article in journal (Refereed) Published
Abstract [en]

The high-resolution Moho depth model is required in various geophysical studies. However, the available models’ resolutions could be improved for this purpose. Large parts of the world still need to be sufficiently covered by seismic data, but existing global Moho models do not fit the present-day requirements for accuracy and resolution. The isostatic models can relatively reproduce a Moho geometry in regions where the crustal structure is in an isostatic equilibrium, but large segments of the tectonic plates are not isostatically compensated, especially along active convergent and divergent tectonic margins. Isostatic models require a relatively good knowledge of the crustal density to correct observed gravity data. To overcome the lack of seismic data and non-uniqueness of gravity inversion, seismic and gravity data should be combined to estimate Moho geometry more accurately. In this study, we investigate the performance of two techniques for combining long- and short-wavelength Moho geometry from seismic and gravity data. Our results demonstrate that both Butterworth and spectral combination techniques can be used to model the Moho geometry. The results show the RMS of Moho depth differences between our model and the reference models are between 1.7 and 4.7 km for the Butterworth filter and between 0.4 and 4.1 km for the spectral combination.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
Moho depth; global Moho model; crust; isostasy; seismic data; spectral combination; gravity inversion; Earth’s interior modeling
National Category
Geophysics Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:hig:diva-41159 (URN)10.3390/rs15061562 (DOI)000957829600001 ()2-s2.0-85151443087 (Scopus ID)
Available from: 2023-03-17 Created: 2023-03-17 Last updated: 2023-08-28Bibliographically approved
Gholamrezaee, S., Bagherbandi, M., Parvazi, K. & Farzaneh, S. (2023). A study on the quality of GNSS signals for extracting the sea level height and tidal frequencies utilizing the GNSS-IR approach. GPS Solutions, 27(2), Article ID 72.
Open this publication in new window or tab >>A study on the quality of GNSS signals for extracting the sea level height and tidal frequencies utilizing the GNSS-IR approach
2023 (English)In: GPS Solutions, ISSN 1080-5370, E-ISSN 1521-1886, Vol. 27, no 2, article id 72Article in journal (Refereed) Published
Abstract [en]

Coastal global navigation satellite system (GNSS) stations equipped with a standard geodetic receiver and antenna enable water level measurement using the GNSS interferometry reflectometry (GNSS-IR) technique. By using GNSS-IR, the vertical distance between the antenna and the reflector surface (e.g., water surface) can be obtained in the vertical (height) reference frame. In this study, the signal-to-noise ratio (SNR) data from four selected stations over three months are used for this purpose. We determined the predominant multipath frequency in SNR data that is obtained using Lomb–Scargle periodogram (LSP) method. The obtained sea surface heights (SSH) are assessed using tide gauge observations regarding accuracy and correlation coefficients. In this study, we investigated daily and hourly GNSS observations and used single frequencies of GPS (L1, L2 and L5), GLONASS (L1 and L2), Galileo (L1, L5, L6, L7 and L8), and BeiDou (L2 and L7) signals to estimate the SSH. The results show that the optimal signals for extracting the SSH are the L1 signal for the GPS, Galileo, and GLONASS systems and the L2 signal for the BeiDou system. The accuracy and correlation parameters for the optimal GPS signal in the daily mode are 2 cm and 0.87, respectively. The same parameters for the optimal GLONASS signal are 4 cm and 0.91. However, the obtained accuracy and correlation coefficients using the best Galileo and BeiDou signals are reduced, i.e., 4 cm and 0.88 using Galileo and 12 cm and 0.52 by employing the Galileo signals, respectively. Our results also show that the GPS L1 signal is more consistent with the tide gauge data. In the following, using the time series derived from the L1 signal and tide gauge readings, the tidal frequencies are extracted and compared using the Least Square Harmonic Estimation (LS-HE) approach. The findings demonstrate that 145 significant tidal frequencies can be extracted using the GNSS-IR time series. The existence of an acceptable correlation between the tidal frequencies of the GNSS-IR and the tide gauge time series indicates the usefulness of the GNSS-IR time series for tide studies. From our results, we can conclude that the GNSS-IR technique can be applied in coastal locations alongside tide gauge measurements for a variety of purposes.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Frequency analysis; GNSS interferometry reflectometry; LS-HE; Remote sensing; Sea level height; Tide-gauge
National Category
Signal Processing Oceanography, Hydrology and Water Resources Geophysics
Identifiers
urn:nbn:se:hig:diva-41117 (URN)10.1007/s10291-023-01416-6 (DOI)000937182700004 ()2-s2.0-85148448236 (Scopus ID)
Available from: 2023-02-23 Created: 2023-02-23 Last updated: 2023-03-24Bibliographically approved
Bagherbandi, M. (2023). A study on the quality of GNSS signals for extracting the sea level height and tidal frequencies utilizing the GNSS-R approach. In: : . Paper presented at Presentation at the Nordic Geodetic Commision, Working Group Geodynamics and Earth Observation, at Aalto University, Otaniemi, Finland 14 -15 March 2023.
Open this publication in new window or tab >>A study on the quality of GNSS signals for extracting the sea level height and tidal frequencies utilizing the GNSS-R approach
2023 (English)Conference paper, Oral presentation with published abstract (Other (popular science, discussion, etc.))
National Category
Signal Processing Oceanography, Hydrology and Water Resources Geophysics
Identifiers
urn:nbn:se:hig:diva-41118 (URN)
Conference
Presentation at the Nordic Geodetic Commision, Working Group Geodynamics and Earth Observation, at Aalto University, Otaniemi, Finland 14 -15 March 2023
Available from: 2023-02-23 Created: 2023-02-23 Last updated: 2023-02-24Bibliographically approved
Bagherbandi, M., Farzaneh, S., Gholamrezaee, S. & Parvazi, K. (2023). How accurate are GNSS signals for extracting sea level height and tidal frequencies using GNSS-R technique?. In: : . Paper presented at XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) (Berlin 2023).
Open this publication in new window or tab >>How accurate are GNSS signals for extracting sea level height and tidal frequencies using GNSS-R technique?
2023 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Remote sensing observations of Essential Climate Variables (ECVs) provide a means of studying their global and regional impacts. Coastal GNSS stations measure water levels using GNSS Reflectometry (GNSS-R) technique by determining the vertical distance between the antenna and the water surface. In this study, GNSS-R data from four stations over three months were used to estimate sea surface heights (SSH) and assess accuracy using nearest tide gauge observations. Results showed that GNSS signals from GPS, GLONASS, Galileo, and BeiDou were accurate for the SSH estimation. In addition, 145 significant tidal frequencies were extracted using the GNSS-R and tide gauge time series by employing the Least Square Harmonic Estimation (LS-HE) approach. The study demonstrates the usefulness of GNSS-R for tide studies and its potential use alongside tide gauge measurements in coastal locations.

National Category
Signal Processing Oceanography, Hydrology and Water Resources Geophysics
Identifiers
urn:nbn:se:hig:diva-42823 (URN)10.57757/IUGG23-0557 (DOI)
Conference
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) (Berlin 2023)
Available from: 2023-08-11 Created: 2023-08-11 Last updated: 2023-08-14Bibliographically approved
Jouybari, A., Bagherbandi, M. & Nilfouroushan, F. (2023). Numerical Analysis of GNSS Signal Outage Effect on EOPs Solutions Using Tightly Coupled GNSS/IMU Integration: A Simulated Case Study in Sweden. Sensors, 23(14), Article ID 6361.
Open this publication in new window or tab >>Numerical Analysis of GNSS Signal Outage Effect on EOPs Solutions Using Tightly Coupled GNSS/IMU Integration: A Simulated Case Study in Sweden
2023 (English)In: Sensors, E-ISSN 1424-8220, Vol. 23, no 14, article id 6361Article in journal (Refereed) Published
Abstract [en]

The absence of a reliable Global Navigation Satellite System (GNSS) signal leads to degraded position robustness in standalone receivers. To address this issue, integrating GNSS with inertial measurement units (IMUs) can improve positioning accuracy. This article analyzes the performance of tightly coupled GNSS/IMU integration, specifically the forward Kalman filter and smoothing algorithm, using both single and network GNSS stations and the post-processed kinematic (PPK) method. Additionally, the impact of simulated GNSS signal outage on exterior orientation parameters (EOPs) solutions is investigated. Results demonstrate that the smoothing algorithm enhances positioning uncertainty (RMSE) for north, east, and heading by approximately 17–43% (e.g., it improves north RMSE from 51 mm to a range of 42 mm, representing a 17% improvement). Orientation uncertainty is reduced by about 60% for roll, pitch, and heading. Moreover, the algorithm mitigates the effects of GNSS signal outage, improving position uncertainty by up to 95% and orientation uncertainty by up to 60% using the smoothing algorithm instead of the forward Kalman filter for signal outages up to 180 s.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
GNSS/INS integration; forward Kalman filter; smoothing algorithm; tightly coupled; PPK; virtual reference station; aerial photogrammetry
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-42795 (URN)10.3390/s23146361 (DOI)001039024700001 ()37514655 (PubMedID)2-s2.0-85166022553 (Scopus ID)
Available from: 2023-08-01 Created: 2023-08-01 Last updated: 2023-11-23Bibliographically approved
Bagherbandi, M., Shirazian, M., Ågren, J. & Horemuz, M. (2023). Physical and Geometric Effects on the Classical Geodetic Observations in Small-Scale Control Networks. Journal of Surveying Engineering, 149(1), Article ID 04022014.
Open this publication in new window or tab >>Physical and Geometric Effects on the Classical Geodetic Observations in Small-Scale Control Networks
2023 (English)In: Journal of Surveying Engineering, ISSN 0733-9453, E-ISSN 1943-5428, Vol. 149, no 1, article id 04022014Article in journal (Refereed) Published
Abstract [en]

In classical two-dimensional (2D) geodetic networks, reducing slope distances to horizontal ones is an important task for engineers. These horizontal distances along with horizontal directions are used in 2D geodetic adjustment. The common practice for this reduction is the use of vertical angles to reduce distances using trigonometric rules. However, one faces systematic effects when using vertical angles. These effects are mainly due to refraction, deflection of the vertical (DOV), and the geometric effect of the reference surface (sphere or ellipsoid). To mitigate refraction and DOV effects, one can choose to observe the vertical angles reciprocally if the baseline points’ elevation difference is small. This paper quantifies these effects and proposes a proper solution to eliminate the effects in small-scale geodetic networks (where the longest distances are less than 5 km). The goal is to calculate slope distances into horizontal ones appropriately. For this purpose, we used the SWEN17_RH2000 quasigeoid model (in Sweden) to study the impact of the DOV applying different baseline lengths, azimuths, and vertical angles. Finally, we propose an approach to study the impact of the geometric effect on vertical angles. We illustrate that the DOV and the geometric effects on vertical angles measured reciprocally are significant if the height difference of the start point and endpoint in the baseline is large. Geometric correction should be considered for the measured vertical angles to calculate horizontal distances correctly if the network points are not on the same elevation, even if the vertical angles are measured reciprocally. 

Place, publisher, year, edition, pages
ASCE, 2023
Keywords
Deflections of the vertical (DOV); Geodetic network; Geometric effects; Normal skewness; Refraction; Vertical angle
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:hig:diva-40010 (URN)10.1061/(asce)su.1943-5428.0000407 (DOI)000899310700006 ()2-s2.0-85139919757 (Scopus ID)
Available from: 2022-09-28 Created: 2022-09-28 Last updated: 2023-01-19Bibliographically approved
Bagherbandi, M., Shirazian, M., Amin, H. & Horemuz, M. (2023). Time transfer and significance of vertical land motion in relativistic geodesy applications: a review paper. Frontiers in Earth Science, 11, Article ID 1139211.
Open this publication in new window or tab >>Time transfer and significance of vertical land motion in relativistic geodesy applications: a review paper
2023 (English)In: Frontiers in Earth Science, E-ISSN 2296-6463, Vol. 11, article id 1139211Article, review/survey (Refereed) Published
Abstract [en]

Determination of the Earth’s gravity field and geopotential value is one of the fundamental topics in physical geodesy. Traditional terrestrial gravity and precise leveling measurements can be used to determine the geopotential values at a local or regional scale. However, recent developments in optical atomic clocks have not only rapidly improved fundamental science but also contributed to applied research. The latest generation of optical clocks is approaching the accuracy level of 10−18 when facilitating atomic clock networks. These systems allow examining fundamental theories and many research applications, such as atomic clocks applications in relativistic geodesy, to precisely determine the Earth’s gravity field parameters (e.g., geopotential values). According to the theory of relativistic geodesy, the frequency difference measured by an optical clock network is related to the gravity potential anomaly, provided that the effects of disturbing signals (i.e., tidal and non-tidal contributions) are filtered out. The relativistic geodesy principle could be used for a practical realization of global geodetic infrastructure, most importantly, a vertical datum unification or realization of height systems. This paper aims to review the background of relativistic (clock-based) geodesy and study the variations of optical atomic clock measurements (e.g., due to hydrology loading and land motion).

Place, publisher, year, edition, pages
Frontiers, 2023
Keywords
relativistic geodesy, geodetic reference system, optical atomic clocks, time transfer, frequency analysis, geodetic height systems, datum unification
National Category
Infrastructure Engineering Other Engineering and Technologies not elsewhere specified Signal Processing
Identifiers
urn:nbn:se:hig:diva-42070 (URN)10.3389/feart.2023.1139211 (DOI)001020785200001 ()2-s2.0-85164145319 (Scopus ID)
Available from: 2023-06-11 Created: 2023-06-11 Last updated: 2023-08-28Bibliographically approved
Bagherbandi, M., Shirazian, M., Ågren, J., Horemuz, M. & Karimi, H. (2022). A new approach for reducing physical and geometric effects in small-scale geodetic control networks. In: : . Paper presented at General Assembly, Nordic Geodetic Commission (NKG), Copenhagen, Denmark, 5-8 September 2022.
Open this publication in new window or tab >>A new approach for reducing physical and geometric effects in small-scale geodetic control networks
Show others...
2022 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:hig:diva-40012 (URN)
Conference
General Assembly, Nordic Geodetic Commission (NKG), Copenhagen, Denmark, 5-8 September 2022
Available from: 2022-09-28 Created: 2022-09-28 Last updated: 2022-10-03Bibliographically approved
Bagherbandi, M., Shirazian, M., Ågren, J., Horemuz, M. & Karimi, H. (2022). A new approach for reducing physical and geometric effects in small-scale geodetic control networks: Challenges and Solutions. In: : . Paper presented at Geodesidagarna 2022, Infra City i Upplands-Väsby, Sweden, 5–6 October 2022.
Open this publication in new window or tab >>A new approach for reducing physical and geometric effects in small-scale geodetic control networks: Challenges and Solutions
Show others...
2022 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:hig:diva-40014 (URN)
Conference
Geodesidagarna 2022, Infra City i Upplands-Väsby, Sweden, 5–6 October 2022
Available from: 2022-09-28 Created: 2022-09-28 Last updated: 2022-10-03Bibliographically approved
Jouybari, A., Bagherbandi, M. & Nilfouroushan, F. (2022). Comparison of the strip- and block-wise aerial triangulation using different exterior orientation parameters weights. Journal of Spatial Science, 67(3), 377-394
Open this publication in new window or tab >>Comparison of the strip- and block-wise aerial triangulation using different exterior orientation parameters weights
2022 (English)In: Journal of Spatial Science, ISSN 1449-8596, Vol. 67, no 3, p. 377-394Article in journal (Refereed) Published
Abstract [en]

In this study, three different procedures: checkpoint RMS of residuals, statistical evaluation of AT results using t-test, and comparison of a photogrammetric digital surface model (DSM) and LiDAR data are used to analyse the effect of IMU and GNSS uncertainties on the final adjusted results. The outcome suggests that the method of block-wise GNSS shift correction is the better method for aerial triangulation and one should use appropriate observable weights in AT. The comparison of checkpoint RMS residuals between the two methods shows that the block-wise solution is on average 6cm more accurate than the strip-wise solution.

Place, publisher, year, edition, pages
Taylor & Francis, 2022
Keywords
Photogrammetry, Direct georeferencing, INS/GNSS Integration
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:hig:diva-35211 (URN)10.1080/14498596.2020.1871086 (DOI)000614777300001 ()2-s2.0-85100533681 (Scopus ID)
Available from: 2021-02-04 Created: 2021-02-04 Last updated: 2022-09-21Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0910-0596

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