ICEBEAR: Recent Results from a Bistatic Coded Continuous-Wave E-region Coherent Scatter Radar

2020 ◽  
Author(s):  
Devin Huyghebaert ◽  
Adam Lozinsky ◽  
Glenn Hussey ◽  
Kathryn McWilliams ◽  
Draven Galeschuk ◽  
...  
Keyword(s):  
Plasma Density ◽  
Continuous Wave ◽  
Random Noise ◽  
Azimuthal Angle ◽  
Elevation Angle ◽  
Field Of View ◽  
Angle Of Arrival ◽  
Coherent Scatter ◽  
Scatter Radar ◽  
E Region

<p>The Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar (ICEBEAR) is located in Canada and has a field of view centered at (58°N, 106°W) overlooking the terrestrial auroral zone.  This 49.5 MHz coherent scatter radar measures plasma density irregularities in the E-region ionosphere using a pseudo random noise phase modulated continuous-wave (CW) signal.  ICEBEAR uses this coded CW signal to obtain simultaneous high temporal (1 s) and spatial (1.5 km) resolutions of E-region plasma density turbulence over a 600 km x 600 km field of view, providing insights into the Farley-Buneman plasma density instability and wave-like structures evident in the coherent scatter.  The initial results from ICEBEAR were obtained with a 1D receiving array, providing azimuthal angle of arrival details of the incoming scattered signal.  This azimuthal determination, along with the range determined using the coded signal, allowed the scatter to be mapped in 2D.  A recent reconfiguration of the receiving array has allowed the elevation angle of the received signal to be calculated, providing 3D determination of the location of the plasma density irregularities.  This presentation will demonstrate the capabilities of ICEBEAR, displaying measurements of highly dynamic plasma density irregularities with wave-like behaviour on 1 second time scales.</p>

Comparisons Between E-region Coherent Scatter and Swarm-E Fast Auroral Imager Measurements

2021 ◽  
Author(s):  
Devin Huyghebaert ◽  
Kathryn McWilliams ◽  
Glenn Hussey ◽  
Andrew Howarth ◽  
Stephanie Erion ◽  
...  
Keyword(s):  
Plasma Density ◽  
Continuous Wave ◽  
Field Of View ◽  
Coherent Scatter ◽  
Similar Region ◽  
Scatter Radar ◽  
E Region ◽  
Radar Measurements ◽  
Auroral Emissions ◽  
Auroral Imager

<p>The Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar (ICEBEAR) is a VHF coherent scatter radar that makes measurements of the E-region ionosphere with a field of view centered on ≈ 58°N, 106°W.  This overlaps with the Saskatoon SuperDARN radar field of view, providing the opportunity for multi-frequency coherent scatter radar measurements in a similar region.  In conjunction with these coherent scatter radar measurements, the Swarm-E, or e-POP, satellite Fast Auroral Imager (FAI) has been used to make measurements of auroral emissions in the 650-1100 nm wavelength band over the same field of view.  The primary emission species in this wavelength range are N<sub>2</sub>, O<sub>2</sub>, and N<sub>2</sub><sup>+</sup>, which correspond to energetic charged particle precipitation penetrating into the lower altitudes of the ionosphere.  This makes the FAI a great instrument for comparison studies with E-region coherent scatter.  In addition to this, the FAI is able to be slewed to a location allowing for extended conjunction windows between the imager and the coherent scatter radars.  With recent advances in radar hardware and processing the temporal and spatial resolutions of these different instruments are becoming comparable (~ 1 s, 1.5 km), providing an excellent opportunity to study plasma density irregularities in the E-region ionosphere in great detail.  Comparisons between the coherent scatter radar and FAI measurements are presented, providing insights into how E-region plasma density irregularities correspond to the location of auroral emissions at 650-1100 nm wavelengths.</p>

scholarly journals Artificial E-region field-aligned plasma irregularities generated at pump frequencies near the second electron gyroharmonic

2009 ◽  
Vol 27 (7) ◽  
pp. 2711-2720 ◽  
Author(s):  
D. L. Hysell ◽  
E. Nossa
Keyword(s):  
Plasma Density ◽  
Hybrid Wave ◽  
Pump Frequency ◽  
Coherent Scatter ◽  
Wave Trapping ◽  
Plasma Irregularities ◽  
Ionospheric Modification ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

Abstract. E region ionospheric modification experiments have been performed at HAARP using pump frequencies about 50 kHz above and below the second electron gyroharmonic frequency. Artificial E region field-aligned plasma density irregularities (FAIs) were created and observed using the imaging coherent scatter radar near Homer, Alaska. Echoes from FAIs generated with pump frequencies above and below 2Ωe did not appear to differ significantly in experiments conducted on summer afternoons in 2008, and the resonance instability seemed to be at work in either case. We argue that upper hybrid wave trapping and resonance instability at pump frequencies below the second electron gyroharmonic frequency are permitted theoretically when the effects of finite parallel wavenumbers are considered. Echoes from a sporadic E layer were observed to be somewhat weaker when the pump frequency was 50 kHz below the second electron gyroharmonic frequency. This may indicate that finite parallel wavenumbers are inconsistent with wave trapping in thin sporadic E ionization layers.

scholarly journals Common volume coherent and incoherent scatter radar observations of mid-latitude sporadic E-layers and QP echoes

2004 ◽  
Vol 22 (9) ◽  
pp. 3277-3290 ◽  
Author(s):  
D. L. Hysell ◽  
M. F. Larsen ◽  
Q. H. Zhou
Keyword(s):  
Large Scale ◽  
Incoherent Scatter Radar ◽  
Coherent Scatter ◽  
Electrostatic Waves ◽  
Incoherent Scatter ◽  
Scatter Radar ◽  
Dual Beam ◽  
Sporadic E Layers ◽  
E Region ◽  
Sporadic E

Abstract. Common-volume observations of sporadic E-layers made on 14-15 June 2002 with the Arecibo incoherent scatter radar and a 30MHz coherent scatter radar imager located on St. Croix are described. Operating in dual-beam mode, the Arecibo radar detected a slowly descending sporadic E-layer accompanied by a series of dense E-region plasma clouds at a time when the coherent scatter radar was detecting quasi-periodic (QP) echoes. Using coherent radar imaging, we collocate the sources of the coherent scatter with the plasma clouds observed by Arecibo. In addition to patchy, polarized scattering regions drifting through the radar illuminated volume, which have been observed in previous imaging experiments, the 30MHz radar also detected large-scale electrostatic waves in the E-region over Puerto Rico, with a wavelength of about 30km and a period of about 10min, propagating to the southwest. Both the intensity and the Doppler shifts of the coherent echoes were modulated by the wave.

scholarly journals Measurements of the 3.3 μm Diffuse Galactic Emission Feature with AROME

1990 ◽  
Vol 139 ◽  
pp. 212-213
Author(s):  
M. Giard ◽  
F. Pajot ◽  
J. M. Lamarre ◽  
G. Serra
Keyword(s):  
Surface Brightness ◽  
Galactic Plane ◽  
Elevation Angle ◽  
Emission Feature ◽  
Field Of View ◽  
Interstellar Matter ◽  
Galactic Emission ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules ◽  
Ir Emission

AROME∗ is a balloon-borne experiment which was built to carry out measurements of IR emission features in the diffuse galactic flux. The field of view is 0.5° and surface brightness gradients are detected through azimuthal scanning at a constant elevation angle. The detection of a feature is done by comparison of the fluxes measured in narrow and wide photometric bands centered on the feature's wavelength. Two flights have been performed (August 1987, October 1988), which detected a 3.3 μm feature in the direction of the galactic plane −6° < b < 6°, 60° > l > −50°. Since this feature is characteristic of aromatic C-H bonds, we assigned it to the emission of transiently heated polycyclic aromatic hydrocarbon molecules (PAHs). With this assumption, AROME measurements show that PAHs are an ubiquitous component of the interstellar matter which contain about 10% of the available cosmic carbon.

Research on Physical MPPT of Photovoltaic Array System Based on Image Processing

2013 ◽  
Vol 321-324 ◽  
pp. 1138-1144
Author(s):  
Chao Liu ◽  
Jing Hui
Keyword(s):  
Image Processing ◽  
Tracking Error ◽  
Elevation Angle ◽  
Image Sensor ◽  
Azimuth Angle ◽  
Field Of View ◽  
The Sun ◽  
Photovoltaic Array ◽  
Point Tracking ◽  
Power Point

Based on analyzing the development and the performance feature of existing solar tracker, we propose a solar Maximum Power Point Tracking (MPPT) strategy which combines photoelectric sensor and image processing. Firstly, photoelectric tracking mode positions the sun in the field of view of the image sensor. Then, the position of the sun image is captured by the image sensor. After that, we can find the coordinates of the sun spot in the field of view through image binarization processing. According to the number of steps of stepper motor rotation which is calculated by the deviation of coordinates, the controller drives the biaxial photosensitive (PV) array tracking device, making the sun spot always fall in the centre of the image. Tests show that the elevation angle and azimuth angle of the tracking range of the photovoltaic array are both 0～270°.The average tracking error of elevation angle is less than 0.7°, and the average tracking error of azimuth angle is less than 0.5°.

scholarly journals Mapping ionospheric backscatter measured by the SuperDARN HF radars – Part 2: Assessing SuperDARN virtual height models

2008 ◽  
Vol 26 (4) ◽  
pp. 843-852 ◽  
Author(s):  
T. K. Yeoman ◽  
G. Chisham ◽  
L. J. Baddeley ◽  
R. S. Dhillon ◽  
T. J. T. Karhunen ◽  
...  
Keyword(s):  
Large Scale ◽  
Elevation Angle ◽  
Field Measurements ◽  
Companion Paper ◽  
Hf Radar ◽  
Propagation Path ◽  
Angle Of Arrival ◽  
Virtual Height ◽  
F Region ◽  
Propagation Paths

Abstract. The Super Dual Auroral Radar Network (SuperDARN) network of HF coherent backscatter radars form a unique global diagnostic of large-scale ionospheric and magnetospheric dynamics in the Northern and Southern Hemispheres. Currently the ground projections of the HF radar returns are routinely determined by a simple rangefinding algorithm, which takes no account of the prevailing, or indeed the average, HF propagation conditions. This is in spite of the fact that both direct E- and F-region backscatter and 1½-hop E- and F-region backscatter are commonly used in geophysical interpretation of the data. In a companion paper, Chisham et al. (2008) have suggested a new virtual height model for SuperDARN, based on average measured propagation paths. Over shorter propagation paths the existing rangefinding algorithm is adequate, but mapping errors become significant for longer paths where the roundness of the Earth becomes important, and a correct assumption of virtual height becomes more difficult. The SuperDARN radar at Hankasalmi has a propagation path to high power HF ionospheric modification facilities at both Tromsø on a ½-hop path and SPEAR on a 1½-hop path. The SuperDARN radar at Þykkvibǽr has propagation paths to both facilities over 1½-hop paths. These paths provide an opportunity to quantitatively test the available SuperDARN virtual height models. It is also possible to use HF radar backscatter which has been artificially induced by the ionospheric heaters as an accurate calibration point for the Hankasalmi elevation angle of arrival data, providing a range correction algorithm for the SuperDARN radars which directly uses elevation angle. These developments enable the accurate mappings of the SuperDARN electric field measurements which are required for the growing number of multi-instrument studies of the Earth's ionosphere and magnetosphere.

scholarly journals Mapping ionospheric backscatter measured by the SuperDARN HF radars – Part 1: A new empirical virtual height model

2008 ◽  
Vol 26 (4) ◽  
pp. 823-841 ◽  
Author(s):  
G. Chisham ◽  
T. K. Yeoman ◽  
G. J. Sofko
Keyword(s):  
Elevation Angle ◽  
Propagation Path ◽  
Angle Of Arrival ◽  
Velocity Measurements ◽  
Actual Distribution ◽  
Virtual Height ◽  
Radar Network ◽  
Straight Line ◽  
Target Locations ◽  
Height Model

Abstract. Accurately mapping the location of ionospheric backscatter targets (density irregularities) identified by the Super Dual Auroral Radar Network (SuperDARN) HF radars can be a major problem, particularly at far ranges for which the radio propagation paths are longer and more uncertain. Assessing and increasing the accuracy of the mapping of scattering locations is crucial for the measurement of two-dimensional velocity structures on the small and meso-scale, for which overlapping velocity measurements from two radars need to be combined, and for studies in which SuperDARN data are used in conjunction with measurements from other instruments. The co-ordinates of scattering locations are presently estimated using a combination of the measured range and a model virtual height, assuming a straight line virtual propagation path. By studying elevation angle of arrival information of backscatterred signals from 5 years of data (1997–2001) from the Saskatoon SuperDARN radar we have determined the actual distribution of the backscatter target locations in range-virtual height space. This has allowed the derivation of a new empirical virtual height model that allows for a more accurate mapping of the locations of backscatter targets.

scholarly journals Improvement of the Angle of Arrival Measurement Accuracy for Indoor UWB Localization

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
N. Awarkeh ◽  
J.-C. Cousin ◽  
M. Muller ◽  
N. Samama
Keyword(s):  
Measurement Accuracy ◽  
Continuous Wave ◽  
Energy Detection ◽  
Angle Measurement ◽  
Phase Correlation ◽  
Ultra Wideband ◽  
Line Of Sight ◽  
Angle Of Arrival ◽  
Localization System ◽  
Classical Energy

This paper shows that the accuracy of azimuth angle measurement for an interferometric localization system used to locate tags in its Line-of-Sight (LoS) can be improved by exploiting Impulse Radio-Ultra WideBand (IR-UWB) signals and without increasing the frequency bandwidth. This solution uses a Phase Correlation (PC) method, initially applied for Continuous Wave (CW) signals, adapted for Ultra WideBand (UWB) pulse signals. The obtained results are compared to those computed by a classical Energy Detection (ED) method where it becomes impossible to estimate azimuth angles for tag positions close to the orthogonal centered axis of the localization system baseline.

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