scholarly journals Optimized merging of search coil and fluxgate data for MMS

2016 ◽  
Vol 5 (2) ◽  
pp. 521-530 ◽  
Author(s):  
David Fischer ◽  
Werner Magnes ◽  
Christian Hagen ◽  
Ivan Dors ◽  
Mark W. Chutter ◽  
...  
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Model Development ◽  
Flight Data ◽  
Frequency Bands ◽  
Search Coil ◽  
Precise Knowledge ◽  
Combining Data ◽  
Magnetospheric Multiscale Mission ◽  
Compensation Approach

Abstract. The Magnetospheric Multiscale mission (MMS) targets the characterization of fine-scale current structures in the Earth's tail and magnetopause. The high speed of these structures, when traversing one of the MMS spacecraft, creates magnetic field signatures that cross the sensitive frequency bands of both search coil and fluxgate magnetometers. Higher data quality for analysis of these events can be achieved by combining data from both instrument types and using the frequency bands with best sensitivity and signal-to-noise ratio from both sensors. This can be achieved by a model-based frequency compensation approach which requires the precise knowledge of instrument gain and phase properties. We discuss relevant aspects of the instrument design and the ground calibration activities, describe the model development and explain the application on in-flight data. Finally, we show the precision of this method by comparison of in-flight data. It confirms unity gain and a time difference of less than 100 µs between the different magnetometer instruments.

scholarly journals Optimized Merging of Search Coil and Fluxgate Data for MMS

2016 ◽  
Author(s):  
David Fischer ◽  
Werner Magnes ◽  
Christian Hagen ◽  
Ivan Dors ◽  
Mark W. Chutter ◽  
...  
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Model Development ◽  
Frequency Bands ◽  
Search Coil ◽  
Precise Knowledge ◽  
Combining Data ◽  
Unity Gain ◽  
Magnetospheric Multiscale Mission ◽  
Compensation Approach

Abstract. The Magnetospheric Multiscale mission (MMS) targets the characterization of fine scale current structures in the Earth's tail and magnetopause. The high speed of these structures, when traversing one of the MMS spacecraft, creates magnetic field signatures that cross the sensitive frequency bands of both search coil and fluxgate magnetometers. Higher data quality for analysis of these events can be achieved by combining data from both instrument types and using the frequency bands with best sensitivity and signal to noise ratio from both sensors. This can be achieved by a model based frequency 20 compensation approach which requires the precise knowledge of instrument gain and phase properties. We discuss relevant aspects of the instrument design, the ground calibration activities, describe the model development and explain the application on in-flight data. Finally, we show the precision of this method by comparison of inflight data. It confirms unity gain and a time difference of less than 100 μs between the different magnetometer instruments.

scholarly journals An overview of rain attenuation research in Bangladesh

2021 ◽  
Vol 23 (2) ◽  
pp. 902
Author(s):  
Md Abdus Samad ◽  
Md. Razu Ahmed ◽  
Syed Zahidur Rashid
Keyword(s):  
Signal To Noise Ratio ◽  
Model Development ◽  
Rain Attenuation ◽  
Climatic Conditions ◽  
Telecommunication Networks ◽  
60 Ghz ◽  
Attenuation Model ◽  
Frequency Bands ◽  
Backbone Networks ◽  
June July

The demands of shifting to the operating frequency of wireless telecommunication systems at new higher frequency bands increase as day by day the necessity to transfer more data volume through wireless networks. Bangladesh has launched its first satel-lite, Bangabandhu-1, with 40 communication channels in the C and Ku frequency bands. Besides, a huge volume of terrestrial microwave backbone networks suffer from fading during rain across the country. Bangladesh experiences heavy rainfall in June-July-August. The rain has a remarkable impact on deteriorating the signal-to-noise ratio at the receiver end. To implement the 5G network, 2.6–60 GHz frequency bands are promising. However, the propagated waves in these bands are prone to fadedue to rain. Unfortunately, the rain attenuation model developed for other climatic conditions can not be used readily without customization. In this regard, to maintain quality telecommunication networks, proper rain attenuation model development is crucial. This work reviews rain attenuation research in Bangladesh, global research trends and the research scope to manage rain attenuation.

40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rabiu Imam Sabitu ◽  
Nafizah Goriman Khan ◽  
Amin Malekmohammadi
Keyword(s):  
System Performance ◽  
High Speed ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Threshold Power ◽  
Modulation Format ◽  
Transmission Distance ◽  
Mode Division Multiplexing ◽  
Speed Mode

AbstractThis report examines the performance of a high-speed MDM transmission system supporting four nondegenerate spatial modes at 10 Gb/s. The analysis adopts the NRZ modulation format to evaluate the system performance in terms of a minimum power required (PN) and the nonlinear threshold power (PTH) at a BER of 10−9. The receiver sensitivity, optical signal-to-noise ratio, and the maximum transmission distance were investigated using the direct detection by employing a multimode erbium-doped amplifier (MM-EDFA). It was found that by properly optimizing the MM-EDFA, the system performance can significantly be improved.

Investigation on Evaluation of Terminal Departure Capacity Based on Route Intersection

2013 ◽  
Vol 655-657 ◽  
pp. 2262-2265
Author(s):  
Jian Guo Kong
Keyword(s):  
Mathematical Model ◽  
Traffic Flow ◽  
Air Traffic ◽  
Flow Management ◽  
Air Traffic Flow Management ◽  
Flight Data ◽  
Proposed Model ◽  
Combining Data ◽  
Traffic Flow Management ◽  
Airport Terminal

Air traffic flow management is the key to evaluate airspace capacity reasonably and accurately. Based on the flight features of terminal route intersection, this paper builds a mathematical model for scattered flight of departure aircraft, and then evaluates the terminal capacity based on this model. By combining data from Flight Data Recorder (FDR) and flight schedule with the model, an example-runway 02R of Guangzhou Baiyun airport terminal was given to show the effectiveness of the proposed model.

scholarly journals Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

2004 ◽  
Vol 4 (3) ◽  
pp. 621-626 ◽  
Author(s):  
D. Janches ◽  
M. C. Nolan ◽  
M. Sulzer
Keyword(s):  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Side Lobe ◽  
Beam Axis ◽  
Main Beam ◽  
High Signal ◽  
Precise Knowledge ◽  
Dual Beam ◽  
Arecibo Observatory ◽  
Meteoric Material

Abstract. Precise knowledge of the angle between the meteor vector velocity and the radar beam axis is one of the largest source of errors in the Arecibo Observatory (AO) micrometeor observations. In this paper we study ~250 high signal-to-noise ratio (SNR) meteor head-echoes obtained using the dual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal the distribution of this angle. All of these meteors have been detected first by the radar first side lobe, then by the main beam and finally seen in the side lobe again. Using geometrical arguments to calculate the meteor velocity in the plane perpendicular to the beam axis, we find that most of the meteors are travelling within ~15° with respect to the beam axis, in excellent agreement with previous estimates. These results suggest that meteoroids entering the atmosphere at greater angles may deposit their meteoric material at higher altitudes explaining at some level the missing mass inconsistency raised by the comparisson of meteor fluxes derived from satellite and traditional meteor radar observations. They also may be the source of the observed high altitude ions and metalic layers observed by radars and lidars respectively.

scholarly journals High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiufeng Li ◽  
Victor T C Tsang ◽  
Lei Kang ◽  
Yan Zhang ◽  
Terence T W Wong
Keyword(s):  
High Resolution ◽  
High Speed ◽  
High Performance ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
High Signal ◽  
Photoacoustic Microscopy ◽  
Mouse Ear

AbstractLaser diodes (LDs) have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy (PAM). However, the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously. In this paper, we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD, operating at a pulsed mode, with a repetition rate of 30 kHz, as an excitation source. A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio. By optimizing the optical system, a high lateral resolution of 4.8 μm has been achieved. In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

scholarly journals A High-Speed, Light-Weight Scalar Magnetometer Bird for km Scale UAV Magnetic Surveying: On Sensor Choice, Bird Design, and Quality of Output Data

2021 ◽  
Vol 13 (4) ◽  
pp. 649
Author(s):  
Arne Døssing ◽  
Eduardo Lima Simoes da Silva ◽  
Guillaume Martelet ◽  
Thorkild Maack Rasmussen ◽  
Eric Gloaguen ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Regional Scale ◽  
Weather Conditions ◽  
Light Weight ◽  
Output Data ◽  
Efficient Manner ◽  
Flexible System ◽  
Scalar Data

Magnetic surveying is a widely used and cost-efficient remote sensing method for the detection of subsurface structures at all scales. Traditionally, magnetic surveying has been conducted as ground or airborne surveys, which are cheap and provide large-scale consistent data coverage, respectively. However, ground surveys are often incomplete and slow, whereas airborne surveys suffer from being inflexible, expensive and characterized by a reduced signal-to-noise ratio, due to increased sensor-to-source distance. With the rise of reliable and affordable survey-grade Unmanned Aerial Vehicles (UAVs), and the developments of light-weight magnetometers, the shortcomings of traditional magnetic surveying systems may be bypassed by a carefully designed UAV-borne magnetometer system. Here, we present a study on the development and testing of a light-weight scalar field UAV-integrated magnetometer bird system (the CMAGTRES-S100). The idea behind the CMAGTRES-S100 is the need for a high-speed and flexible system that is easily transported in the field without a car, deployable in most terrain and weather conditions, and provides high-quality scalar data in an operationally efficient manner and at ranges comparable to sub-regional scale helicopter-borne magnetic surveys. We discuss various steps in the development, including (i) choice of sensor based on sensor specifications and sensor stability tests, (ii) design considerations of the bird, (iii) operational efficiency and flexibility and (iv) output data quality. The current CMAGTRES-S100 system weighs ∼5.9 kg (including the UAV) and has an optimal surveying speed of 50 km/h. The system was tested along a complex coastal setting in Brittany, France, targeting mafic dykes and fault contacts with magnetite infill and magnetite nuggets (skarns). A 2.0 × 0.3 km area was mapped with a 10 m line-spacing by four sub-surveys (due to regulatory restrictions). The sub-surveys were completed in 3.5 h, including >2 h for remobilisation and the safety clearance of the area. A noise-level of ±0.02 nT was obtained and several of the key geological structures were mapped by the system.

scholarly journals Error Performance Estimation of Modulated Retroreflective Transdermal Optical Wireless Links with Diversity under Generalized Pointing Errors

Telecom ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 167-180
Author(s):  
George K. Varotsos ◽  
Hector E. Nistazakis ◽  
Konstantinos Aidinis ◽  
Fadi Jaber ◽  
Mohd Nasor ◽  
...  
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Spatial Diversity ◽  
Performance Estimation ◽  
Optical Wireless ◽  
Wireless Data ◽  
Error Performance ◽  
Pointing Errors ◽  
Implanted Medical Devices ◽  
Recent Developments

Recent developments in both optical wireless communication (OWC) systems and implanted medical devices (IMDs) have introduced transdermal optical wireless (TOW) technology as a viable candidate for extremely high-speed in-body to out-of-body wireless data transmissions, which are growing in demand for many vital biomedical applications, including telemetry with medical implants, health monitoring, neural recording and prostheses. Nevertheless, this emerging communication modality is primarily hindered by skin-induced attenuation of the propagating signal bit carrier along with its stochastic misalignment-induced fading. Thus, by considering a typical modulated retroreflective (MRR) TOW system with spatial diversity and optimal combining (OC) for signal reception in this work, we focus, for the first time in the MRR TOW literature, on the stochastic nature of generalized pointing errors with non-zero boresight (NZB). Specifically, under these circumstances, novel analytical mathematical expressions were derived for the total average bit error rate (BER) of various system configurations. Their results revealed significant outage performance enhancements when spatial diversity was utilized. Moreover, taking into consideration the total transdermal pathloss along with the effects of stochastic NZB pointing errors, the critical average signal-to-noise ratio (SNR) metric was evaluated for typical power spectral-density values.

Experimental determination of fragmentation efficiency for Plinian and Pelean eruptions of Mt. Pelée, Martinique

2021 ◽  
Author(s):  
Mila Huebsch ◽  
Ulrich Kueppers ◽  
Guillaume Carazzo ◽  
Anne-Marie Lejeune ◽  
Audrey Michaud-Dubuy ◽  
...  
Keyword(s):  
Grain Size ◽  
Fractal Dimension ◽  
Open Porosity ◽  
High Speed ◽  
Model Development ◽  
Active Volcano ◽  
Petrophysical Properties ◽  
Density Currents ◽  
Fragmentation Efficiency ◽  
Plinian Eruptions

<p>Mt. Pelée is a historically active volcano, situated on the island of Martinique (Lesser Antilles), that has shown a variety of explosive styles in the recent past, ranging from dome-forming (Pelean) to open-vent (Plinian) eruptions.  The 1902-1905 eruption is infamous for the pyroclastic density currents (PDCs) that destroyed the towns of St. Pierre and Morne Rouge, killing 30 000 residents.  Since the last eruption (dome-forming) in 1929-1932, Mt. Pelée was quiet and considered dormant until recently.  In late 2020, the local Volcanological Observatory (OVSM) raised the alert level following a noticeable increase in seismicity, bringing into effect a reinforcement of monitoring resources.  As St. Pierre is long since re-established, along with several other towns along the volcano’s flanks, it is of utmost importance to understand the possible range of eruptive activity to improve the preparedness strategies of local communities.</p><p>The precise controls on eruption dynamics vary across volcanic systems and cannot be constrained via direct observation. However, crucial inferences can be made based on petrophysical properties and mechanical behaviours of erupted materials.  For this study, we collected samples from PDC deposits of Mt. Pelée, from the two historic Pelean (1902-1905, and 1929-1932) and three pre-Columbian Plinian eruptions (1300 CE P1, 280 CE P2, and 79 CE P3). We measured petrophysical properties (density, porosity, permeability) of cylindrical samples drilled from bomb-sized clasts and investigated their fragmentation behaviour via grain size and high-speed video analysis. These results are used in comparison with field data of grain-size distribution (GSD) of individual outcrops and calculated total GSD data.  We investigated the effects of transport-related sorting or fining.</p><p>The “Pelean” samples are found to be denser (32-47% open porosity) than the pumiceous “Plinian” samples (55-66% open porosity).  Moreover, these two classes are distinctly different in their crystallinity as samples underwent different ascent conditions.  In our experiments, distinct fragmentation behaviour and resulting GSDs are observed for samples from each eruption style, regardless of experimental pressure conditions (5-20 MPa). Our results show the paramount importance of open porosity on fragmentation efficiency in pumiceous samples, alongside a strong influence of crystallinity.  The fractal dimension of fragmentation calculated from weight fractions, independent of grain shape, shows clear differences in fragmentation efficiency as a function of sample properties and experimental starting conditions.</p><p>Our results suggest that (i) the variability in porosity and permeability is too low to cause the increased explosivity exhibited during the 1902 eruption compared to the 1929 event, (ii) open porosity has a major control on fragmentation efficiency in pumiceous samples, (iii) fragmentation efficiency can be effectively evaluated by calculating the fractal dimension of the cumulative weight fractions of experimental products.</p><p>The influence of crystallinity and pore textures on fragmentation efficiency must be further investigated to aid hazard model development for future eruptions of Mt. Pelée. Future work will constrain these textural parameters of naturally and experimentally fragmented materials from Mt. Pelée, to further elucidate the controls on eruptive dynamics at this hazardous volcano.</p>

scholarly journals S-SAD phasing on SOLEIL Beamline PROXIMA 1

2014 ◽  
Vol 70 (a1) ◽  
pp. C609-C609
Author(s):  
Patrick Gourhant ◽  
Beatriz Guimaraes ◽  
Tatiana Isabet ◽  
Sebastian Klinke ◽  
Pierre Legrand ◽  
...  
Keyword(s):  
Model Building ◽  
De Novo ◽  
Signal To Noise Ratio ◽  
Beam Line ◽  
Synchrotron Source ◽  
Combining Data ◽  
Low Energies ◽  
Sad Phasing ◽  
Multiple Sample ◽  
Data Collections

"PROXIMA 1, a beamline for macro-molecular crystallography at the 3rd generation synchrotron source SOLEIL, is equipped with a multi-circle goniometer (alpha 50 degrees) as well as a PILATUS 6M detector. These features, along with the extended energy range of the beam line towards the low energies (down to 5.5 keV) and the possibility to adapt the source size to the sample in order to optimize signal to noise ratio, have made the beam line very attractive for S-SAD phasing with more than seven examples of successful de novo phasing achieved over the last two years. The use of low energies has also proved a significant aid in assisting with MODEL building. The technical capabilities of the beam line for low energy data collections will be presented, along with a number of examples of the successful use of low wavelengths on the beam line. The importance of combining data from multiple sample orientations in order to achieve ""true multiplicity"" will be highlighted, as well as the importance of combining data from multiple crystals in order to achieve high multiplicity."

Sign in / Sign up

Export Citation Format

Share Document