scholarly journals Research on calibration method of uniformity of radiation interference field of intense electromagnetic pulse

2021 ◽  
Vol 2076 (1) ◽  
pp. 012102
Author(s):  
Chunliang Fu ◽  
Linhua Gong ◽  
Jiangjing Lin ◽  
Jun Zhou
Keyword(s):  
Radiation Field ◽  
Rapid Development ◽  
Single Point ◽  
Test Site ◽  
Calibration Method ◽  
Test Area ◽  
Test Time ◽  
Frequency Range ◽  
Test Efficiency ◽  
Uniformity Test

Abstract With the rapid development of electronic and electrical products, the working frequency of ite products is higher and higher, the influence frequency range of interference between electronic products is also expanding, the test frequency range of radiation anti-interference is improving, at the same time, more and more attention is paid to the requirements of radiation anti-interference test site. At present, the uniformity of radiation field is mainly realized by single point multiple test, which will inevitably lead to the measurement error due to the time-varying characteristics of the radiation signal itself; In addition, the test time is greatly increased and the test efficiency is low. In order to solve these problems, this paper designs a device which can realize multi-point test at one time and can automatically adjust the test area. The simulation shows that the device can meet the requirement of 9point uniformity test of radiation field in 500mm × 500mm ~ 1500mm × 1500mm area. On this basis, experiments are carried out in 1000mm × 1000mm test area for 1.35GHz and 2.88GHz. The experiments show that the test device can meet the requirement of 9point uniformity test and greatly improve the test efficiency and automation.

scholarly journals UAV BLOCK GEOREFERENCING AND CONTROL BY ON-BOARD GNSS DATA

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 9-16
Author(s):  
G. Forlani ◽  
F. Diotri ◽  
U. Morra di Cella ◽  
R. Roncella
Keyword(s):  
Environmental Protection Agency ◽  
Low Cost ◽  
Single Point ◽  
Test Site ◽  
Ground Control ◽  
Italian Alps ◽  
Ground Control Points ◽  
Remote Sites ◽  
Gnss Data ◽  
And Control

Abstract. Unmanned Aerial Vehicles (UAV) are established platforms for photogrammetric surveys in remote areas. They are lightweight, easy to operate and can allow access to remote sites otherwise difficult (or impossible) to be surveyed with other techniques. Very good accuracy can be obtained also with low-cost UAV platforms as far as a reliable ground control is provided. However, placing ground control points (GCP) in these contexts is time consuming and requires accessibility that, in some cases, can be troublesome. RTK-capable UAV platforms are now available at reasonable costs and can overcome most of these problems, requiring just few (or none at all) GCP and still obtaining accurate results. The paper will present a set of experiments performed in cooperation with ARPA VdA (the Environmental Protection Agency of Valle d’Aosta region, Italy) on a test site in the Italian Alps using a Dji Phantom 4 RTK platform. Its goals are: a) compare accuracies obtainable with different calibration procedures (pre- or on-the-job/self-calibration); b) evaluate the accuracy improvements using different number of GCP when the site allows for it; and c) compare alternative positioning modes for camera projection centres determination, (Network RTK, RTK, Post Processing Kinematic and Single Point Positioning).

Chirp Spreading Spectrum in Imperfect Environment and Wireless Tree Topology Network

2021 ◽  
Author(s):  
Hongqiang Li ◽  
Dongyan Zhao ◽  
Xiaoke Tang ◽  
Jie Gan ◽  
Xu Zhao ◽  
...  
Keyword(s):  
Low Power ◽  
Rapid Development ◽  
Single Point ◽  
Multipath Fading ◽  
Tree Topology ◽  
Area Network ◽  
Wide Area Network ◽  
Target Node ◽  
Long Distance ◽  
And Performance

With the rapid development of IoT technology in recent years, higher requirements have been put forward for wireless communication technology. Low Power Wide Area Network (LPWAN) technology is emerging rapidly, the technology is characterized by low power consumption, low bandwidth, long-distance, and a large number of connections, and is specifically designed for Internet of Things applications. LoRa (Low Power Long Range Transceiver), as a typical representative of LPWAN technology, has been widely concerned and studied. This paper analyzes the performance of LoRa modulation in the tree topology network and analyzes the performance of LoRa modulation in the imperfect environment for point-to-point communication and multipoint-to-point communication. From theoretical analysis and performance simulation, it can be seen that the influence of frequency offset or multipath fading on LoRa signal is very obvious. However, when LoRa modulation is used for networking, multi-user interference will be introduced. Under the influence of many imperfect factors, the signal receiver performance of LoRa modulation will be difficult to guarantee. Because of these effects, Coordinated Multiple Points based on Timing Delay (DCoMP) is presented. Multiple nodes close to each other send the same data to the target node. Due to the inaccurate synchronization between nodes, there will be a certain relative delay when sending signals to the same target node. After the receiving node combines the signals of multiple nodes according to different relative delays, the reception performance of the signals can be improved. At the same time, the cooperative node can also actively adjust the signal sending time to improve the reception performance of the receiving node signal merging algorithm. LoRa modulation, by using DCoMP transmission, improves the reception of signals and thus the overall capacity of the system. Through the analysis of multipoint communication and single point communication, this paper is of great help to LoRa network deployment.

A Simple Permittivity Calibration Method for GPR-Based Road Pavement Measurements

Frequenz ◽  
2016 ◽  
Vol 70 (9-10) ◽  
Author(s):  
Pekka Eskelinen
Keyword(s):  
Dielectric Material ◽  
Quality Measurement ◽  
Cavity Resonator ◽  
Calibration Method ◽  
Frequency Range ◽  
Cylindrical Resonator ◽  
Road Pavement ◽  
Asphalt Quality ◽  
Cylindrical Cavity Resonator

AbstractCylindrical resonator principle can be used in GPR asphalt quality measurement calibration. This method relies on ordinary drill core samples that are regularly taken from measured road sections, but now only analyzed for dimensions, density and sometimes chemically. If such a drill sample is covered with proper conductive surfaces, a cylindrical cavity resonator is formed. The baseline of the GPR permittivity recordings can so be found by measuring the resonance behaviour of this covered sample, which can later still be used for those traditional analyses. A clear benefit is the resonator’s 1–2 GHz frequency range which equals that of common commercial GPR systems. Example results and reference readings from known dielectric material are shown. The obtained uncertainty in this case study is 0.02 units of permittivity, when measuring the same sample repeatedly.

scholarly journals High-Frequency Electromagnetic Induction (HFEMI) Sensor Results from IED Constituent Parts

2019 ◽  
Vol 11 (20) ◽  
pp. 2355 ◽  
Author(s):  
Benjamin Barrowes ◽  
Mikheil Prishvin ◽  
Guy Jutras ◽  
Fridon Shubitidze
Keyword(s):  
High Frequency ◽  
Electromagnetic Induction ◽  
Low Frequency ◽  
Test Site ◽  
Frequency Range ◽  
Discrimination Capability ◽  
Metal Detectors ◽  
Metallic Parts ◽  
Ground Penetrating ◽  
Improvised Explosive

The detection and classification of subsurface improvised explosive devices (IEDs) remains one of the most pressing military and civilian problems worldwide. These IEDs are often intentionally made with either very small metallic parts or less-conducting parts in order to evade low-frequency electromagnetic induction (EMI) sensors, or metal detectors, which operate at frequencies of 50 kHz or less. Recently, high-frequency electromagnetic induction (HFEMI), which extends the established EMI frequency range above 50 kHz to 20 MHz and bridges the gap between EMI and ground-penetrating radar frequencies, has shown promising results related to detecting and identifying IEDs. In this higher frequency range, less-conductive targets display signature inphase and quadrature responses similar to higher conducting targets in the LFEMI range. IED constituent parts, such as carbon rods, small pressure plates, conductivity voids, low metal content mines, and short wires respond to HFEMI but not to traditional low-frequency EMI (LFEMI). Results from recent testing over mock-ups of less-conductive IEDs or their components show distinctive HFEMI responses, suggesting that this new sensing realm could augment the detection and discrimination capability of established EMI technology. In this paper, we present results of using the HFEMI sensor over IED-like targets at the Fort AP Hill test site. We show that results agree with numerical modeling thus providing motives to incorporate sensing at these frequencies into traditional EMI and/or GPR-based sensors.

scholarly journals An evaluation of the performance of Sea-Bird Scientific's SeaFET™ autonomous pH sensor: considerations for the broader oceanographic community

Ocean Science ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 751-768 ◽  
Author(s):  
Cale A. Miller ◽  
Katie Pocock ◽  
Wiley Evans ◽  
Amanda L. Kelley
Keyword(s):  
Spectral Analysis ◽  
Time Series Data ◽  
Single Point ◽  
Ph Sensor ◽  
Calibration Method ◽  
Series Data ◽  
South Central ◽  
Autonomous Sensor ◽  
Robust Measurements

Abstract. The commercially available Sea-Bird SeaFET™ provides an accessible way for a broad community of researchers to study ocean acidification and obtain robust measurements of seawater pH via the use of an in situ autonomous sensor. There are pitfalls, however, that have been detailed in previous best practices for sensor care, deployment, and data handling. Here, we took advantage of two distinctly different coastal settings to evaluate the Sea-Bird SeaFET™ and examine the multitude of scenarios in which problems may arise confounding the accuracy of measured pH. High-resolution temporal measurements of pH were obtained during 3- to 5-month field deployments in three separate locations (two in south-central Alaska, USA, and one in British Columbia, Canada) spanning a broad range of nearshore temperature and salinity conditions. Both the internal and external electrodes onboard the SeaFET™ were evaluated against robust benchtop measurements for accuracy using the factory calibration, an in situ single-point calibration, or an in situ multi-point calibration. In addition, two sensors deployed in parallel in Kasitsna Bay, Alaska, USA, were compared for inter-sensor variability in order to quantify other factors contributing to the sensor's intrinsic inaccuracies. Based on our results, the multi-point calibration method provided the highest accuracy (< 0.025 difference in pH) of pH when compared against benchtop measurements. Spectral analysis of time series data showed that during spring in Alaskan waters, a range of tidal frequencies dominated pH variability, while seasonal oceanographic conditions were the dominant driver in Canadian waters. Further, it is suggested that spectral analysis performed on initial deployments may be able to act as an a posteriori method to better identify appropriate calibration regimes. Based on this evaluation, we provide a comprehensive assessment of the potential sources of uncertainty associated with accuracy and precision of the SeaFET™ electrodes.

scholarly journals Principle for the Realization of Dual-Orthogonal Linearly Polarized Antennas for UWB Technique

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Grzegorz Adamiuk ◽  
Mario Pauli ◽  
Thomas Zwick
Keyword(s):  
Substrate Surface ◽  
Single Point ◽  
Broad Band ◽  
Main Beam ◽  
Cross Polarization ◽  
Frequency Range ◽  
Beam Direction ◽  
Array Configuration ◽  
Uwb Radar ◽  
Linearly Polarized

A concept of an array configuration for an ultrawideband suppression of the cross-polarization is presented. The method is explained in detail, and a mathematical description of the principle is given. It is shown that the presented configuration is convenient for the development of very broad band, dual-orthogonal, linearly polarized antennas with high polarization purity. The investigated configuration shows a high decoupling of the orthogonal ports and is capable for antennas with a main beam direction perpendicular to the substrate surface, that is, for a planar design. The phase center of the antenna configuration remains fixed at one single point over the complete desired frequency range, allowing a minimum dispersion of the radiated signal. The influence of nonidealities in the feeding network on the polarization purity is investigated. The presented method introduces a superior possibility of an extension of typical UWB technique to fully polarized systems, which improves significantly performance in, for example, UWB-MIMO or UWB-Radar.

scholarly journals Microwave usage and cancer: Do microwaves cause cancer?

2021 ◽  
Author(s):  
Muhammad Abdullah Al Azam Abd Rahman ◽  
Zairina A Rahman
Keyword(s):  
Rapid Development ◽  
Microwave Frequency ◽  
Microwave Energy ◽  
Microwave Oven ◽  
The Body ◽  
Surrounding Tissue ◽  
Frequency Range ◽  
Modern Life ◽  
Electrical Appliance ◽  
Fast Lane

Materials containing water, for example foods, fluids or tissues, absorb microwave energy readily, which is then converted into heat. This principle is applied in microwave ovens, an electrical appliance that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. Amidst the hustle and bustle of modern life, the microwave oven has been a great help, as the rapid development of technology keeps consumers in the fast lane. Cancer is defined as the uncontrolled growth and spread of cells. It can affect almost any part of the body. The growths often invade surrounding tissue and can metastasize to distant sites. In this paper, we will explore the function of microwave ovens, the pathophysiology of cancer, and whether is there any evidence of a relationship between microwave ovens and cancer.

scholarly journals CO-REGISTRATION OF MULTITEMPORAL UAV IMAGE DATASETS FOR MONITORING APPLICATIONS: A NEW APPROACH

2016 ◽  
Vol XLI-B1 ◽  
pp. 757-763 ◽  
Author(s):  
I. Aicardi ◽  
N. Nyapwere ◽  
F. Nex ◽  
M. Gerke ◽  
A.M. Lingua ◽  
...  
Keyword(s):  
Rapid Development ◽  
Test Site ◽  
Time Frame ◽  
Reference Image ◽  
Image Block ◽  
Ground Control Points ◽  
Manual Intervention ◽  
Multi Temporal ◽  
Uav Image ◽  
Changes Over Time

In the last years we have witnessed a rapid development of UAVs (Unmanned Aerial Vehicles), especially for image collection. One of the advantages is the possibility to perform high resolution and repeated flights in a cheap way to detect changes over time. Thus, dynamic scenes can be monitored acquiring image blocks in different epochs in a flexible way. <br><br> Anyway, most of UAVs are not able to provide accurate direct geo-referencing information, so image blocks from different epochs still need to be co-registered to efficiently detect changes. This task is mostly completed using GCPs (Ground Control Points), although this approach is time consuming as manual intervention is needed. <br><br> This paper aims at investigating new techniques to automate the co-registration of image blocks without the use of GCPs, just relying on an image based co-registration (IBCR) approach. The image alignment is initially performed on a reference (anchor) epoch and the registration of the following (slave) epochs is performed including some (anchor) images from the reference epoch with fixed external orientation parameters. This allows constraining the Bundle Block Adjustment of the slave epoch to be consistent with the reference one. <br><br> The study involved the use of 10 multi-temporal image block over a large building construction site, and spanning a time frame of 2 years. Different tests have been performed for the reference image choice with a manual approach and then evaluating the reached accuracy. The performed tests on the chosen test site have shown that the accuracy of the proposed methodology provides results comparable to the common GCPs registration approach.

scholarly journals A generic computer assisted intervention plug-in module for 3D Slicer with multiple device support

2009 ◽  
Author(s):  
András Lassó ◽  
Junichi Tokuda ◽  
Siddharth Vikal ◽  
Clare M Tempany ◽  
Nobuhiko Hata ◽  
...  
Keyword(s):  
Rapid Development ◽  
Calibration Method ◽  
Application Framework ◽  
Computer Assisted ◽  
Multiple Views ◽  
Image Transfer ◽  
End User ◽  
Dicom Image ◽  
3D Slicer ◽  
Imaging Mode

Various frameworks and toolkits have been proposed for rapid development of computer assisted intervention (CAI) software. In this paper, we investigate how the open-source 3D Slicer application framework can be used for this purpose. We defined common requirements for CAI software to evaluate and enhance 3D Slicer for interventional applications in general. 3D Slicer is found to be an appropriate end-user deployment environment for CAI software, as its built-in functions fulfill many requirements and missing functionalities can be conveniently added. We describe the implementation of a CAI software based on extending core 3D Slicer functions. Three enhancements are described in detail: the management of workflow, DICOM image transfer, and multiple views. The resulting software fulfills general CAI requirements and supports two different MRI-guided prostate biopsy systems (each with a different imaging mode, robotic manipulator and calibration method), thereby demonstrating the usability of Slicer for implementing different CAI applications.

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