News

We welcome Dr. Anders Tjulin to the Project Team

Dr. Anders Tjulin joins EISCAT as the Project Assistant for the EISCAT_3D projects.

He starts his position 14 September 2009 and will have his office at EISCAT Headquarters in Kiruna.

We welcome him to the Team!

Findings: EISCAT_3D FP6 Design Study Summary

The Final Design Study Report was published 8 June 2009 by the Design Study Project Team. Its findings are summaried in a comprehensive report (link below).

In short, the Design Study recommends a system as follows:

Following extensive consultation with the scientific user community in 2004 and 2005, it was determined that only a multi-static phased array system could reach or approach the performance demanded by present and future users. Accordingly, the target system comprises a central active (transmit-receive) site (the “core”) and four receive-only sites , located on two approximately 250 km long baselines oriented N-S and E-W respectively.

During the four-year study, all mission-critical technical concepts have been modelled, investigated by simulations, in critical cases also by full-scale tests, and found to be realisable. Array sizes, transmitter power levels and receiver noise performance required to reach the desired time and space resolutions have also been established. To reach the desired performance, the target system should have the following technical characteristics:

The core will comprise a 120-m diameter filled circular aperture array with ≈16 000 elements, laid out on an equilateral triangular grid, and a number (6…9) of smaller outlier receive-only arrays. The core will provide: a half-power beamwidth of ≈ 0.75°, a power-aperture product exceeding 100 GW m², grating-lobe free pattern out to 40° zenith angle and graceful degradation in case of single-point equipment failure. Each core array element will be made up from a radiator, a dual 300+300 Watt linear RF power amplifier, a high performance direct-digitising receiver and support electronics. The recommended radiator is a crossed Yagi antenna with a minimum directivity of about 7 dBi.

Four filled 8 000-element receive-only arrays will be installed, two on each baseline at distances of respectively ≈110 and ≈250 km from the core. Their radiating elements will be 3- or 4-element X Yagis, essentially identical to those used in the core. The Yagis will be directed towards the core field-of-view and elevated to 45°. Outlier arrays for interferometry will also be installed.

Advanced digital beam-forming systems will allow the generation of a large number of simultaneous beams from each array, thus eliminating the time/space ambiguity plaguing all present incoherent scatter systems and making true volumetric imaging of vector quantities possible for the first time.

The complete report: www.eiscat.se/groups/EISCAT_3D_info/Deliverable_D11_1.pdf

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