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Surface Reflection Suppression Method for Air-Coupled SFCW GPR Systems
Primož Smogavec, Dušan Gleich, 2025, original scientific article

Abstract: Air-coupled ground penetrating radar (GPR) systems are widely used for subsurface imaging in demining, geological surveys, and infrastructure assessment applications. However, strong surface reflections can introduce interference, leading to receiver saturation and reducing the clarity of subsurface features. This paper presents a novel surface reflection suppression algorithm for stepped-frequency continuous wave (SFCW) GPR systems. The proposed method estimates the surface reflection component and applies phase-compensated subtraction at the receiver site, effectively suppressing background reflections. A modular SFCW radar system was developed and tested in a laboratory setup simulating a low-altitude airborne deployment to validate the proposed approach. B-scan and time-domain analyses demonstrate significant suppression of surface reflections, improving the visibility of subsurface targets. Unlike previous static echo cancellation methods, the proposed method performs on-board pre-downconversion removal of surface clutter that compensates for varying ground distance, which is a unique contribution of this work.
Keywords: GPR systems, ground penetrating radar systems, surface reflection suppression, SFCW, surface echo, echo cancellation, receiver saturation
Published in DKUM: 12.05.2025; Views: 0; Downloads: 7
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Suitability of the double Langevin function for description of anhysteretic magnetization curves in NO and GO electrical steel grades
Simon Steentjes, Martin Petrun, G. Glehn, Drago Dolinar, Kay Hameyer, 2017, original scientific article

Abstract: This paper compares the match obtained using the classical Langevin function, the tanh function as well as a recently by the authors proposed double Langevin function with the measured anhysteretic magnetization curve of three different non-oriented electrical steel grades and one grain-oriented grade. Two standard non-oriented grades and a high-silicon grade (Si content of 6.5%) made by CVD are analyzed. An excellent match is obtained using the double Langevin function, whereas the classical solutions are less appropriate. Thereby, problems such as those due to propagation of approximation errors observed in hysteresis modeling can be bypassed.
Keywords: polarization, magnetization measurement, magnetic materials, hysteresis models, Langevin function, electrical steel, saturation
Published in DKUM: 03.08.2017; Views: 1246; Downloads: 430
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Impact of magnetic saturation on the steady-state operation of the controlled induction motor
Petar Ljušev, Drago Dolinar, Gorazd Štumberger, 2003, original scientific article

Abstract: The paper presents a method for determination of the steady-state torque characteristics of the induction motor in the case of rotor field-oriented control (RFOC) with nonlinear magnetizing characteristic of the iron core included. The torque characteristics are determined for the constant stator current and the constant d-axis stator current. The characteristics obtained at a constant stator current are used to maximize the torque capability of the RFOC induction motor. The aim of the presented work is to obtain required steady-state torque with minimal stator current. Experiments show that the proposed selection of a magnetizing reference is promising.
Keywords: induction motor, torque characteristics, magentic saturation
Published in DKUM: 01.06.2012; Views: 1651; Downloads: 24
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