Elevation angle‐of‐arrival determination for a standard and a modified superDARN HF radar layout

McDonald, Andrew J.; Whittington, J.; Larquier, S. de; Čustović, Edhem; Kane, Thomas A.; Devlin, John

doi:10.1002/2013rs005157

Cited by 14 publications

(15 citation statements)

References 37 publications

(60 reference statements)

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“…There was a distinct saturation effect in the observed elevation for moderate and high solar activity years. This can be explained by peculiarities of the antenna system such as (1) elevation angle aliasing effect at which the maximum measurable elevation is limited by 45° (Milan et al 1997;McDonald et al 2013;Ponomarenko et al 2015) and (2) partially by the narrow elevation radiation pattern (it affects the location of the power maximum that the procedure searches in each sounding session). However, the observed effective height on average agreed well with simulated one.…”

Section: F2mentioning

confidence: 99%

Diurnal and seasonal behavior of the Hokkaido East SuperDARN ground backscatter: simulation and observation

et al. 2016

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We studied regular diurnal and seasonal behaviors of ground backscatter propagation characteristics corresponding to the Hokkaido East Super Dual Auroral Radar Network (SuperDARN) (43.53°N, 143.61°E). Firstly, we simulated key propagation characteristics using a high frequency (HF) calculation technique based on the waveguide approach and International Reference Ionosphere (IRI)-2012 model as background ionosphere. The minimum slant range, skip distance, corresponding elevation angle, and true reflection height were considered in this study. The behaviors of these characteristics were well explained by diurnal and seasonal variations in the critical frequency and maximum height of corresponding ionosphere layer in HF reflection point. We estimated the accuracy of the standard SuperDARN mapping technique and proposed a means for its improvement. Secondly, we constructed an algorithm for mass data processing and extracted diurnal dependencies of the minimum slant range, corresponding elevation angle, and effective reflection height from the Hokkaido East SuperDARN dataset for a period from 2007 to 2014. The algorithm uses the simulated characteristics for distinguishing regular ground backscatter echoes propagating in the E and F2 HF channels. Observed monthly mean and simulated values of the characteristics were compared, and the result showed that the accuracy of IRI-2012 significantly depends on solar activity level and orientation of HF propagation path. In general, the difference between observed and simulated values decreased with increases in solar activity and azimuth. We also analyzed the occurrence of echoes originating behind the radar and found that they most frequently appear in winter and equinoxes before sunrise in beam #0 and after sunset in beam #15. The probability of their observation for a specific local time could reach up to 35 %.

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Section: F2mentioning

confidence: 99%

Diurnal and seasonal behavior of the Hokkaido East SuperDARN ground backscatter: simulation and observation

et al. 2016

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“…Geolocating the scattering volume depends on the ability to accurately estimate the HF propagation path to and from the volume (Greenwald et al, 2017). The SuperDARN radars are equipped with interferometers that make it possible to determine the elevation angle of arrival of the returning radio signals and, consequently, to estimate the most likely propagation modes and propagation path (André et al, 1998;Burrell et al, 2015;Chisham & Freeman, 2013;McDonald et al, 2013;Milan et al, 1997;Shepherd, 2017). Hence, using this information makes it possible to accurately estimate the geographic location of the scattering volume.…”

Section: Introductionmentioning

confidence: 99%

Calibrating SuperDARN Interferometers Using Meteor Backscatter

Chisham

2018

Radio Science

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Accurate geolocation of ionospheric backscatter measured by the Super Dual Auroral Radar Network (SuperDARN) high‐frequency radars is critical for the integrity of polar ionospheric convection maps, which involve combining SuperDARN line‐of‐sight velocity measurements originating from multiple locations. Geolocation requires estimation of the propagation paths of the high‐frequency radio signal to and from the scattering volume. The SuperDARN radars comprise both a main and interferometer antenna array to allow the estimation of the elevation angle of arrival of the returning signal, and hence its most likely propagation path. However, over the history of operation of SuperDARN (>20 years) elevation angle data have not been routinely used owing to problems with the calibration of phase difference measurements. Instead, virtual height models have been used to estimate the most likely propagation paths, and these are often of limited accuracy. Here we present a method for calibrating SuperDARN interferometer measurements using backscatter from meteor trails measured in the near field‐of‐view of the SuperDARN radars. We present estimates of calibration factors for the SuperDARN radar in Saskatoon, Canada, at different temporal resolutions: 3 months, 10 days, and 1 day. The calibration factor varies over the 9‐year interval studied, such that employing a single value for the whole interval would lead to significant errors in elevation angle measurements at times. The higher‐resolution results show the ability of the technique to determine the calibration factor routinely at a high time resolution.

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“…This is because the phase angle in the SuperDARN interferometric measurements is reported between ±π while it actually can be different by multiples of 2π . SuperDARN radars report only the lowest possible elevations 2π , from Milan et al 1997;McDonald et al 2013;Ponomarenko et al 2015Ponomarenko et al , 2018. This ambiguity has not been addressed in the P2011 approach that we implemented in this study.…”

Section: Superdarn Methods Of F Region Peak Electron Density Estimatesmentioning

confidence: 99%

“…The P2011 technique assumes that the elevation angles can be measured for any angle between 0 • and 90 • . In reality, however, because the interferometer base exceeds the radar wavelength by a factor of three to five, the measured elevation angle has an uncertainty (e.g., Milan et al 1997;McDonald et al 2013;Ponomarenko et al 2015Ponomarenko et al , 2018 in that a single reported value of can correspond to several propagation paths in the ionosphere. This is because the phase angle in the SuperDARN interferometric measurements is reported between ±π while it actually can be different by multiples of 2π .…”

Section: Superdarn Methods Of F Region Peak Electron Density Estimatesmentioning

confidence: 99%

Comparison of SuperDARN peak electron density estimates based on elevation angle measurements to ionosonde and incoherent scatter radar measurements

Koustov

Ullrich

Ponomarenko

et al. 2020

Earth Planets Space

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Measurements of the electron density at the F region peak by the Canadian Advanced Digital Ionosonde (CADI) and the Resolute Incoherent Scatter Radar (RISR) are used to assess the quality of peak electron density estimates made from elevation angle measurements by the Super Dual Auroral Radar Network (SuperDARN) high-frequency radar at Rankin Inlet (RKN). All three instruments monitor the ionosphere near Resolute Bay. The CADI-RKN joint dataset comprises measurements between 2008 and 2017 while RISR-RKN dataset covers about 60 daylong events in 2016. Reasonable agreement between the RKN estimates and measurements by CADI and RISR is shown. Two minor discrepancies are discussed: RKN radar daytime peak electron density overestimation by ~ 10% and underestimation by up to 30% in other time sectors. In winter nighttime and dawn, cases were identified in which the RKN radar significantly overestimates the peak electron density. This occurs when the phase in the RKN interferometer measurements is incorrectly shifted by 2π , and this is most significant when electron densities are low. Statistical fitting to the joint data sets, split into four time sectors of a day, has been done and parameters of the fit have been determined. These allow slight adjustment of measured real-time RKN values to better reflect real peak electron densities in the ionosphere within its field of view.

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Elevation angle‐of‐arrival determination for a standard and a modified superDARN HF radar layout

Cited by 14 publications

References 37 publications

Diurnal and seasonal behavior of the Hokkaido East SuperDARN ground backscatter: simulation and observation

Diurnal and seasonal behavior of the Hokkaido East SuperDARN ground backscatter: simulation and observation

Calibrating SuperDARN Interferometers Using Meteor Backscatter

Comparison of SuperDARN peak electron density estimates based on elevation angle measurements to ionosonde and incoherent scatter radar measurements

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