| 1. |
- Schlatter, Nicola Manuel, et al.
(författare)
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Auroral ion acoustic wave enhancement observed with a radar interferometer system
- 2015
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 33:7, s. 837-844
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of naturally enhanced ion acoustic line (NEIAL) echoes obtained with a five-antenna interferometric imaging radar system are presented. The observations were conducted with the European Incoherent SCATter (EIS-CAT) radar on Svalbard and the EISCAT Aperture Synthesis Imaging receivers (EASI) installed at the radar site. Four baselines of the interferometer are used in the analysis. Based on the coherence estimates derived from the measurements, we show that the enhanced backscattering region is of limited extent in the plane perpendicular to the geomagnetic field. Previously it has been argued that the enhanced backscatter region is limited in size; however, here the first unambiguous observations are presented. The size of the enhanced backscatter region is determined to be less than 900 x 500 m, and at times less than 160m in the direction of the longest antenna separation, assuming the scattering region to have a Gaussian scattering cross section in the plane perpendicular to the geomagnetic field. Using aperture synthesis imaging methods volumetric images of the NEIAL echo are obtained showing the enhanced backscattering region to be aligned with the geomagnetic field. Although optical auroral emissions are observed outside the radar look direction, our observations are consistent with the NEIAL echo occurring on field lines with particle precipitation.
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| 2. |
- Vierinen, J., et al.
(författare)
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Space debris observation potential with EISCAT 3D
- 2018
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Ingår i: 2ND URSI ATLANTIC RADIO SCIENCE MEETING (AT-RASC). - : IEEE. - 9789082598735
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Konferensbidrag (refereegranskat)abstract
- We investigate the capabilities of the next generation ionospheric research radar EISCAT 3D (E3D) for space debris observations. We have used the current projected design of E3D as basis of this study. To model the performance of E3D for space debris observations, we have included basic radar equation based error analysis for range and range-rate observations. Because the radar will be multi-static, it is also capable of observing instantaneous three-dimensional vector velocities and positions by observing round-trip range and range-rate between the transmitter and three receiver sites. We have included error estimates for both of the the three-dimensional position and three-dimensional vector velocity observations. To estimate the fraction of total debris that can be observed with E3D, we have used the MASTER model. We have also investigated effects of radio wave propagation. E3D uses a relatively low VHF frequency (233 MHz), which experiences more radio wave propagation effects than more conventional higher frequency space surveillance radars. Our modeling shows that ionospheric ray-bending and group delay are severe enough that these effects need to be modeled in order to determine accurate orbital elements. As EISCAT 3D is an ionospheric research radar, there will be high quality ionospheric electron density measurements that can be utilized for radio propagation modeling.
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