Searched for: author:"Haji Mohammadloo, T."
(1 - 11 of 11)
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Simons, D.G. (author), Dierikx, Ben (author), Bicknese, Simon (author)
Methods for gridding multibeam echo sounder (MBES) measurements to equidistant grids are proposed as alternatives to the shallowest measured depth, which is affected by outliers. The approaches considered use a combination of mean and standard deviation of soundings and the regression coefficient from the best fitted plane. These methods...
journal article 2019
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Amiri Simkooei, A. (author), Simons, D.G. (author)
Nowadays Multi-Beam Echo-Sounder (MBES) systems are used for obtaining information of the sea/river bed bathymetry and sediment composition. For the latter, use is usually made of the backscatter strength and depth derivatives, such as depth residuals. However, the depth derivatives are affected by the uncertainties inherent to the MBES varying...
conference paper 2019
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Amiri Simkooei, A. (author), Simons, D.G. (author)
Nowadays Multi-Beam Echo-Sounder (MBES) derived bathymetry is used for a large range of applications. However, these measurements are affected by the uncertainties inherent to the MBES. Since the development of the depth uncertainty prediction model, MBES systems have been improved noticeably. The present contribution addresses the importance of...
conference paper 2019
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Renoud, Weston (author), Beaudoin, Jonathan (author), Simons, D.G. (author)
In this contribution a method for correcting bathymetric measurements affected by inaccurate water column sound speed pro_les (SSPs) is presented. The method exploits the redundancy in the multibeam echosounder measurements obtained from the overlap of adjacent swaths by minimizing the difference between depths along overlapping swaths. Two...
journal article 2019
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Simons, D.G. (author)
In this contribution bathymetric uncertainties induced by the use of frequency modulated (FM) signals for multi-beam-echo-sounder (MBES) measurements are quantified and their relevance for MBES bathymetric uncertainty predictions is assessed. When switching to FM, the quality of depth measurements can get deteriorated due to the Doppler...
journal article 2018
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Beaudoin, Jonathan (author), Renoud, Weston (author), Haji Mohammadloo, T. (author), Snellen, M. (author)
In a world of high precision sensors, one of the few remaining challenges in multibeam echosounding is that of refraction-based uncertainty. A poor understanding of oceanographic variability or a poor choice of equipment can lead directly to poor quality bathymetric data. Post-processing software tools have existed for some time to allow data...
conference paper 2018
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Simons, D.G. (author), Dierikx, Ben (author), Bicknese, Simon (author)
Reliable information about the seafloor and river-bed bathymetry is of high interest for a large number of applications. A Multi-Beam echo sounder (MBES) system is able to produce high-resolution bathymetry data at relatively small cost. These measurements, providing a depth for each beam and every ping, are processed to obtain a more ordered...
journal article 2018
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Simons, D.G. (author)
The most recent generation multi-beam echosounders (MBES) allows to transmit Frequency Modulated (FM) signals, in addition to the more conventional Continuous Wave (CW) pulses. In this contribution, the effect of using these FM pulses for bathymetric measurements is investigated. Advantage of using FM signals is that measurements can be taken at...
conference paper 2017
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Amiri Simkooei, A. (author), Haji Mohammadloo, T. (author), Argus, D.F. (author)
The second reprocessing of all GPS data gathered by the Analysis Centers of IGS was conducted in late 2013 using the latest models and methodologies. Improved models of antenna phase center variations and solar radiation pressure in JPL’s reanalysis are expected to significantly reduce errors. In an earlier work, JPL estimates of position time...
journal article 2017
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Haji Mohammadloo, T. (author), Tengku Ali, T.A. (author), Snellen, M. (author), Koop, L. (author), Gaida, T.C. (author), Simons, D.G. (author)
Knowing the morphology and sediment composition of the seabed is of high importance for various applications. In this contribution, the repeatability of acoustic seafloor classification (ASC) results obtained from MBES backscatter value is investigated. The unsupervised classification algorithm based on Principal Component Analysis has been...
conference paper 2017
document
Haji Mohammadloo, T. (author), Snellen, M. (author), Simons, D.G. (author), Dierikx, Ben (author), Bicknese, Simon (author)
conference paper 2017
Searched for: author:"Haji Mohammadloo, T."
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