Multipurpose incoherent scatter measurement and data analysis techniques for EISCAT3D

Abstract

EISCAT3D will be a high-power, high-duty-cycle, large-aperture multistatic radar system with digitally steerable aperture array antennas and solid-state transmitters. The advanced technology enables the system to form multiple simultaneous beams at each radar site and to use advanced transmission modulation techniques. Multipurpose transmission modulations that use the same radar pulses for probing all altitude regions of the ionosphere, as well as the lag profile inversion technique needed for deconvolving autocorrelation functions (ACFs) of the scattering process from the received signal at selected altitudes, have previously been developed for monostatic, single-beam radars. We generalize the concept of multipurpose modulations for multistatic, multibeam systems and introduce a lag profile inversion tool that can perform the ACF deconvolution with modest computing power. We also show that lag profile inversion is not needed for the analysis of remote receiver data or D region pulse-to-pulse correlations. We deconvolve incoherent scatter ACFs from synthetic radar signals that correspond to a possible EISCAT3D multipurpose mode by means of lag profile inversion and fit plasma parameters to the deconvolved ACFs using an analysis tool that makes optimal use of data from all receive beams of the multistatic, multibeam system. The results demonstrate that the multibeam remote receivers provide significant benefits: the remote receiver data have less incoherent scatter self-noise than the core transceiver site data, they enable one to fill gaps critical for E region plasma parameter fits in monostatic ACF data, the data are accurate enough for E region ion-neutral collision frequency fits, and they enable D region measurements with arbitrary transmission modulations. We benchmark computational requirements of the lag profile inversion analysis and use both synthetic radar signal and real measurements with the KAIRA radio receiver and EISCAT VHF incoherent scatter radar to demonstrate D region measurements with a multibeam remote receiver.