Separability Analysis of Integrated Spaceborne Radar and Optical Data: Sudan Case Study

2017 ◽  
Vol 5 (1) ◽  
pp. 10-21 ◽  
Author(s):  
Barry Haack ◽  
Ron Mahabir
Keyword(s):  
Optical Data ◽  
Spaceborne Radar

scholarly journals Exploring the synergy between Landsat and ASAR towards improving thematic mapping accuracy of optical EO data

2020 ◽  
Author(s):  
Alexander R. Brown ◽  
George Petropoulos ◽  
Konstantinos P. Ferentinos
Keyword(s):  
Land Use ◽  
Statistical Significance ◽  
Phase 1 ◽  
Confusion Matrix ◽  
Radar Data ◽  
Added Value ◽  
Optical Data ◽  
Practical Applications ◽  
Synergistic Approach

Earth Observation (EO) provides a unique means of obtaining information on land use/cover and of its changes, which is of key importance in many scientific and practical applications. EO data is already widely used, for example, in environmental practices or decision-making related to food availability and security. As such, it is imperative to examine the suitability of different EO datasets, including their synergies, in respect to their ability to create products and tools for such practices and to guide effectively such decisions. This work aims at exploring the added value of the synergistic use of optical and radar data (from the Landsat TM and Advanced Synthetic Aperture Radar (ASAR) sensors respectively). Such information can help towards improving the accuracy of land cover classifications from EO datasets. As a case study, the region of Wales in theUK has been used. Two classifications—one based on optical data alone and another one developed from the synergy of optical and RADAR datasets acquired nearly, concurrently were developed for the studied region. Evaluation of the derived land/use cover maps was performed on the basis of the confusion matrix using validation points derived from a Phase 1 habitat map of Wales. The results showed 15% increase in overall accuracy (84% from 69%) and kappa coefficient (0.81 from 0.65) using the synergistic approach over the scenario where only optical data were used in the classification. In addition, McNemar’s test was used to assess the statistical significance of the obtained results. Results of this test provided further confirmed that the use of optical data synergistically with the radar data provides more accurate land use/cover maps in comparison with the use of optical data alone.

Electrodynamics surrounding polar cap auroral arcs

2021 ◽  
Author(s):  
Amalie Ø. Hovland ◽  
Kjellmar Oksavik ◽  
Jone P. Reistad ◽  
Marc R. Hairston
Keyword(s):  
High Latitude ◽  
Optical Data ◽  
Polar Cap ◽  
Ionospheric Convection ◽  
Ion Drift ◽  
Polar Latitude ◽  
Mesoscale Structure ◽  
Radar Network ◽  
Auroral Arcs

<p>This multi-instrument case study investigates the electrodynamics surrounding polar cap auroral arcs. A long-lasting auroral arc is observed in the high latitude dusk-sector at ~80° Apex latitude in the northern hemisphere. Ion drift measurements from the SSIES system on the DMSP spacecraft have been combined with multiple ground-based observations. Line of sight velocity data from three polar latitude high-frequency Super Dual Auroral Radar Network (SuperDARN) radars show mesoscale structure in the ionospheric convection in the region surrounding the arc. The convection electric field in this region is modelled using a Spherical Elementary Convection Systems (SECS) technique, using curl-free basis functions only. The result is a regional model of the ionospheric convection based on the fairly dense and distributed flow observations and the curl-free constraint. The model is compared to optical data of the auroral arc from two high latitude Redline Emission Geospace Observatory (REGO) all-sky imagers as well as UV images and particle measurements from the DMSP spacecraft to describe the local electrodynamics in the vicinity of the high latitude arc throughout the event.</p>

scholarly journals Observations of omega bands using an imaging riometer

2009 ◽  
Vol 27 (11) ◽  
pp. 4183-4195 ◽  
Author(s):  
A. J. Kavanagh ◽  
J. A. Wild ◽  
F. Honary
Keyword(s):  
Current System ◽  
Optical Data ◽  
Hall Conductance ◽  
Coherent Scatter ◽  
Noise Absorption ◽  
Using Data ◽  
Set Up ◽  
Cosmic Noise ◽  
First Time

Abstract. We present a case study of an omega band current system from 11 May 1998 using data from the Imaging Riometer for Ionospheric Studies (IRIS) in Finland. For the first time, images of a substorm-related omega band in cosmic noise absorption are shown. The substorm in question was one of a string that occurred on that day; inspection of geostationary satellite data indicates that this was a sawtooth event. Using a previously established statistical relationship, the IRIS data is used to provide maps of Hall conductance and compared with previous estimates utilising both HF and VHF coherent-scatter radars. Discrepancies are discussed with reference to precipitation spectrum and the geometry of the experimental set-up. The imaging riometer data provides a higher spatial resolution than the combined magnetometer-radar pairing for determining the Hall conductance and can also be used to identify the extent of the precipitation in the absence of optical data.

Capstan Design and Control for Drawing Optical Fiber: A Case Study in Mechatronics Design

2007 ◽  
Author(s):  
Hodge E. Jenkins ◽  
Mark L. Nagurka
Keyword(s):  
Optical Fiber ◽  
Process Model ◽  
Systems Approach ◽  
Fiber Diameter ◽  
Fiber Quality ◽  
Optical Data ◽  
Glass Temperature ◽  
Simulation Studies ◽  
And Control

This paper presents a case study on the design of a draw capstan drive with feedback control for use in optical fiber manufacturing. Optical fiber is manufactured by the draw process, which involves heating and pulling high purity glass cylinders to diameters of 125 micron. Of critical concern is producing a constant diameter for the glass fiber and its lightguide core. The diameter of the optical fiber must remain constant to create a product capable of transmitting high-bandwidth optical data. The optical fiber draw capstan design has a significant impact on the resulting fiber quality. As the draw speed is used to control the fiber diameter, the ability of the draw capstan to follow velocity commands directly affects the resulting fiber diameter. In this case study a systems approach is used for the design of the mechanical and control aspects through parametric evaluations and modeling, as well as simulation studies of the capstan drive. Disturbances in the draw process arise from sources such as the variation in the diameter of the input glass cylinder and the draw tension control, affecting the glass temperature and viscosity. Simulation studies demonstrate that speed regulation, to manufacture optical fiber within allowable diameter tolerances, is achievable in the presence of representative disturbances. The capstan model and design along with the fiberdrawing process model presented in this case study are suitable for undergraduate and graduate courses in system dynamics, control, and mechatronics. As is typical of many problems in manufacturing processes, the problem discussed is multidisciplinary. The study highlights the use of mechanical and electrical modeling, system identification, and control design as necessary parts of product and process improvement.

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