Adaptive sidelobe suppression to mitigate interference from hard targets in EISCAT_3D

EISCAT_3D is an international research infrastructure consisting of multiple phased-array incoherent-scatter radars in the northmost areas of Norway, Finland, and Sweden. Since EISCAT_3D is capable of rapid and flexible beam steering with a high transmission power, it is considered to be potentially dual-use, as it could be used to track any objects in orbit, including military satellites. Hence, the radar system has a software component that automatically filters out the echoes from hard targets in real-time, called Hard Target Echo Removal (HTER). There are many satellites and space debris in orbit nowadays, and a large amount of data would be discarded if the HTER procedure was too simple just to throw data packets with hard target echoes.
Meanwhile, each antenna array of EISCAT_3D is composed of multiple receivers, enabling adaptive array signal processing. The direction of arrivals for the incoherent scatter and interference from hard targets would be different, as the former comes from the main lobe while the latter from the sidelobe; hence, the interference would be efficiently suppressed with the directionally-constrained minimization of power (DCMP) approach with a constraint to the loss of the signal-to-noise ratio for the incoherent scattering signal.
In this presentation, the effectiveness of the adaptive array signal processing is demonstrated on a simulation with realistic settings of the standard experiment of the EISCAT_3D to mitigate the number of discarded data with the HTER processing.