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The Seventh Asia-Pacific Conference on Environmental Electromagnetics (CEEM'2015)

作者： Luo Genxin Xiang Dong Li Hao Science and Technology on Near-surface Detection Laboratory First Research Institute of General Armament Department Engineering Corps

The ultra-wide spectrum(UWS) high-power microwave(HPM) device produces great interference on vehicle-mounted electrical equipment during *** the developing process of equipment of certain type,a series of effective measures are proposed based on the features of electromagnetic radiation and conduction,which adopt EMI filter,electromagnetic shielding,certain electromagnetic interference suppressors and other technical means,so as to address the effects of HPM radiation on vehicle-mounted equipment and achieve the application of HPM technology in the engineering equipment for the first *** Paper combines the methods and experience accumulated in the development process of equipment,analyzes the mechanism and efficacy of different methods for electromagnetic shielding,obtains the optimization solution for UWS- HPM shielding and provides a practical and effective technical way to solve the difficulty of UWS- HPM shielding.

关键词： high-power microwave electromagnetic radiation electromagnetic shielding

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Simulation Study on Parachute-type High Power EMP Radiator

Simulation Study on Parachute-type High Power EMP Radiator

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The Seventh Asia-Pacific Conference on Environmental Electromagnetics (CEEM'2015)

作者： Zhu Yichao Zheng Shoujun Pan Shenghan Wu Sang Science and Technology on Near-surface Detection Laboratory First Research Institute of General Armament Department Engineering Corps

Rotating parabolic reflector antenna combined with parachute is designed to have a parachute-type high power EMP *** EM array complementary radiation as the design idea,a four-feed-arm parachute-type reflector antenna structure with higher feeding efficiency is proposed,thus to strengthen the low-frequency radiating capacity,widen the bandwidth of antenna and improve the radiant efficiency of antenna;a balanced feeding structure is also adopted to strengthen the radiating *** results showed that parachute-type radiator is superior to TEM horn antenna in bom peak-to-peak value of field strength and effective bandwidth of radiation field,thus making effective radiation of high-power UWB-EMP come true.

关键词： feed parabolic reflector EMP antenna

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Kinetics of first order magnetostructural transition in single crystalline FeRh thin film

Kinetics of first order magnetostructural transition in sing...

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International Conference on Magnetics (INTERMAG)

作者： W. Lu Y. Xu X. Fang Y. Song X. Li School of Materials Science and Engineering Tongji University Shanghai National Key Laboratory of Science Technology Near-surface Detection and Sensing Technology Wuxi University of Shanghai for Science and Technology Shanghai

This study reports the temperature- and time-dependent magnetization of the ferromagnetic phase in epitaxial FeRh thin films across the antiferromagnetic-ferromagnetic transition on both heating and cooling process by vibrating sample magnetometry. The thin films are deposited on MgO (001) substrates by co-evaporation method and vacuum annealed at 700 K for 2 h. X-ray diffraction is employed for structural characterization. Results from the magnetization curves indicate that the nucleation and growth behaviors of the single crystalline thin film are similar to crystallization of solids.

关键词： Magnetic hysteresis Magnetization Frequency modulation Temperature measurement Magnetic films Amorphous magnetic materials Magnetic fields

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Cascaded Sliding Window Based Real-Time 3D Region Proposal for Pedestrian detection*

Cascaded Sliding Window Based Real-Time 3D Region Proposal f...

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IEEE International Conference on Robotics and Biomimetics

作者： Jun Hu Tao Wu Hao Fu Zhiyu Wang Kai Ding College of Intelligence Science and Technology National University of Defense Technology Changsha China Science and Technology on Near-Surface Detection Laboratory Wuxi China

Pedestrian detection is an indispensable technology for designing autonomous driving systems. This paper proposes a cascaded sliding window based real-time approach to generate 3D pedestrian proposals on point clouds only. After rasterizing the raw point cloud, a 3D sliding window is adopted to extract pedestrian candidates. Two features are proposed to improve the proposal performance. One is the central points density feature, which acts as a filter to speed up the process and reduce false alarms. The other is the location feature, including the density distribution and height difference distribution of the point cloud, which describes the profile and location of an object in a sliding window. The scores generated by this feature are then applied to non-maximum suppression (NMS) to remove sub-optimal boxes. Experiments on the KITTI 3D object detection benchmark show that our approach achieves state-of-the-art results among comparable methods, while maintaining the speed and accuracy trade-off.

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detection of UXO-like Targets with Portable Transient Electromagnetic System

Detection of UXO-like Targets with Portable Transient Electr...

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Jun Zhu Haiyang Zhang Yuelin Xu Yu Qiu Shuang Zhang Shudong Chen Science and Technology on Near-Surface Detection Laboratory Wuxi China College of Electronic Science and Engineering Jilin University Changchun China

With the advantages of strong anti-interference ability and high spatial resolution, electromagnetic induction (EMI) has proven to be successful in unexploded ordnance (UXO detection. Portable transient electromagnetic system can work in a variety of complex conditions where the large and heavy vehicular systems cannot be readily used. The detection of UXO-like targets with portable transient electromagnetic (TEM) system is discussed detailed in this paper. Firstly, with description of the single dipole model for UXO response approximation, the location and characteristic response extraction for UXO-like targets is talked with the DE algorithm. Then, the improved sensor of the portable TEM system with a single-layered transmitting coil and five 3-component receiving coils is introduced. The transmitting coil is constructed with a diameter, number of turns, and transmitting current of 0.5 m, 30, and 5 A, respectively. The receiving coil is constructed with a length, number of turns, and resonant frequency of 6 cm, 600, and 180 kHz, respectively. Finally, 12 UXOs and 6 harmless targets buried in the area of 10 m × 6 m at different depths in different orientations have been detected with the improved portable TEM system. Target location and characteristic response have been estimated by DE algorithm with the measured response. The experimental results show that the high-quality data provided by the improved portable TEM system combined with the DE algorithm based on the dipole model can locate and characterize the separated targets accurately. Most of the position errors are within 10cm in x position and 5cm in depths for separated buried targets. For the multiple-targets buried together, the system can still locate and characterize the targets even if the response of two targets overlaps.

关键词： Tensile stress Mathematical model Magnetic moments Perpendicular magnetic recording Magnetic fields Transient analysis

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Bucking coil used in unexploded ordnance detection with transient electromagnetic system

Bucking coil used in unexploded ordnance detection with tran...

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Hejun Jiang Xinqun Luan Jun Hao Shuang Zhang Shudong Chen Science and Technology on Near-Surface Detection Laboratory Wuxi China College of Electronic Science and Engineering Jilin University Changchun China

Off-time response is usually measured by transient electromagnetic (TEM) system to detect subsurface targets. Compared with off-time response, on-time response of TEM system is more sensitive to high-conductivity targets, such as UXOs. However, it is difficult to obtain on-time response directly due to the strong primary field response. The key problem for on-time measurement is to eliminate the primary field response. Bucking coil is adopted here to compensation the primary field of transmitter coil at receiving coil for on-time response measuring. Firstly, the structure of the sensor with transmitting coil, bucking coil, and receiving coil is presented. Then, the primary field of transmitting coil and bucking coil at the position of receiving coil is calculated theoretically. With the side length of transmitting coil, bucking coil and the receiving coil fixed, the number of turns for transmitting coil and bucking coil are optimized for the best compensation. Calculated results show that the best compensation effect can reach 0.53%. Finally, the sensor with a transmitting coil (constructed with a side length and number of turns of 96 cm and 30, respectively), a bucking coil (constructed with a side length and number of turns of 26 cm and 8, respectively), and a receiving coil (constructed with a side length of 6 cm) was built. Measured results show that the primary field response after compensation is no more than 1% of the original response, and the maximum amplitude is only 0.4V. The on-time response of targets can be accurately recorded.

关键词： Geophysical measurements Magnetic field measurement Pollution measurement Current measurement Magnetic flux Transient analysis

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Location of Buried Target with Method of Auxiliary Sources

Location of Buried Target with Method of Auxiliary Sources

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Shan Liang Shuang Zhang Shudong Chen Zhaohe Liu College of Electronic Science and Engineering Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi China

It is a key problem to locate a buried target in UXO detection. The inversion algorithm based on the principle of least squares requires a large number of forward calculations to estimate the position of a target. The method of auxiliary sources (MAS) which can directly locate a UXO-like target is presented here without forward calculation. With a brief description of single dipole model for a UXO-like target, the basis of target location with magnetic field and scalar magnetic potential is deduced theoretically. Auxiliary sources made of elementary magnetic dipoles on a plane are applied to estimate the equivalent scalar magnetic potential from the measured magnetic field. Firstly, the moment of elementary magnetic dipoles is estimated by matching the measured magnetic field with the auxiliary sources modeled field. Then, the equivalent scalar magnetic potential is calculated with these elementary magnetic dipoles without a priori knowledge of the target's location. Finally, the position is calculated directly with the measured magnetic field and the equivalent scalar magnetic potential. The responses of four UXOs excited by a z-component square transmitting coil are recorded by a 9×9 3-component receiving coil array. With the auxiliary sources on a plane under the measurement grid, the equivalent scalar magnetic potential is calculated precisely. Experimental results show that the measured magnetic field matches well with the auxiliary sources modeled field, and the estimated positions of all targets are highly consistent with the measured ones. The horizontal error is within 2 cm, and the depth error is within 6 cm.

关键词： Magnetic field measurement Magnetic fields Position measurement Mathematical model Magnetometers Geophysical measurements Transient analysis

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Throwing-mine detection based on azimuth coherence

Throwing-mine detection based on azimuth coherence

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International Conference on Computational Problem-Solving (ICCP)

作者： Han-tao Sun Chang Wen-ge Zhao-he Liu National University of Defense Technology Changsha Hunan CN Science and Technology on Near-Surface Detection Laboratory Wuxi 214035 China

Throwing-mine detection is a typical problem of low RCS (radar cross section) targets detection in heavy clutter, in which the high false alarm rate is a difficult problem. Classical CFAR (Constant False Alarm Rate) detection algorithm only utilizes the image contrast characteristics, in the case of low SNR (Signal to Noise Ratio), a large number of false alarms generates. In order to further reduce false alarm rate, CFAR-IHP (Constant False Alarm Rate-Internal Hermitian Product) detection algorithm is proposed in this paper. CFAR-IHP is based on CFAR and target azimuth coherence characteristic, therefore, we first get the sub-aperture image sequence to extract target azimuth information by the sub-aperture processing algorithm for SAR image. Lastly, based on Ku-band SAR data, we use CFAR-IHP (Constant False Alarm Rate-Internal Hermitian Product) algorithm to detect the targets, experimental results show that the method further eliminate the clutter and the azimuth coherence helpfully reduces the false alarms.

关键词： Azimuth Coherence Synthetic aperture radar Clutter Image sequences Object detection Doppler effect

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Real-time 3D Single Object Tracking with Transformer

arXiv

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arXiv 2022年

作者： Shan, Jiayao Zhou, Sifan Cui, Yubo Fang, Zheng The Faculty of Robot Science and Engineering Northeastern University Shenyang China Science and Technology on Near-Surface Detection Laboratory Wuxi China

LiDAR-based 3D single object tracking is a challenging issue in robotics and autonomous driving. Currently, existing approaches usually suffer from the problem that objects at long distance often have very sparse or partially-occluded point clouds, which makes the features extracted by the model ambiguous. Ambiguous features will make it hard to locate the target object and finally lead to bad tracking results. To solve this problem, we utilize the powerful Transformer architecture and propose a Point-Track-Transformer (PTT) module for point cloud-based 3D single object tracking task. Specifically, PTT module generates fine-tuned attention features by computing attention weights, which guides the tracker focusing on the important features of the target and improves the tracking ability in complex scenarios. To evaluate our PTT module, we embed PTT into the dominant method and construct a novel 3D SOT tracker named PTT-Net. In PTT-Net, we embed PTT into the voting stage and proposal generation stage, respectively. PTT module in the voting stage could model the interactions among point patches, which learns context-dependent features. Meanwhile, PTT module in the proposal generation stage could capture the contextual information between object and background. We evaluate our PTT-Net on KITTI and NuScenes datasets. Experimental results demonstrate the effectiveness of PTT module and the superiority of PTT-Net, which surpasses the baseline by a noticeable margin, ∼10% in the Car category. Meanwhile, our method also has a significant performance improvement in sparse scenarios. In general, the combination of transformer and tracking pipeline enables our PTT-Net to achieve state-of-the-art performance on both two datasets. Additionally, PTT-Net could run in real-time at 40FPS on NVIDIA 1080Ti GPU. Our code is open-sourced for the research community at https://***/shanjiayao/PTT. © 2022, CC BY.

关键词： Optical radar

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UXO localization procedures applied to potable TEM sensor

UXO localization procedures applied to potable TEM sensor

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Yu Qiu Shuang Zhang Shudong Chen Chaopeng Luo College of Electronic Science and Engineering Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi China

Localization of unexploded ordnance (UXO) with transient electromagnetic (TEM) system is a principle and necessary problem in detection procedures, especially beset by low data diversity and high positioning uncertainty. In this paper, procedures for targets location are presented in detail with cued data collected by potable TEM sensor JPMD, which is designed to provide diverse time-domain data of high quality with one transmitter coil and five 3-component receiving coils. Based on the single dipole model, the target is located with the data collected at a single spatial point by the differential evolution (DE) optimization algorithm which can be subdivided into three steps. With the structure and parameters of JPMD sensors and data inversion process described briefly, a field test site of 5 m × 5 m measurement grid was conducted to present the specific UXO localization procedures at Jilin University. Results indicate that all the UXO-like targets can be detected distinctly with JPMD. The location of single object can be inversed rapid in tolerable error at one single point. For two objects with overlapping signals as one, the inverted horizontal position is basically in the middle of them and depth is a bit smaller than theory.

关键词： Data models Magnetic field measurement Electromagnetics Optimization Time measurement Mathematical model Linear programming

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