EUSO-SPB2 Fluorescence Telescope Calibration and Field Tests

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2), successfully launched from Wanaka, New Zealand on May 13, 2022, is a precursor for a space-based astroparticle observatory such as the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA). EUSO-SPB2 flew two custom telescopes. Both have UV/UV-visible sensitivity and feature Schmidt optics. The Fluorescence Telescope (FT) measures ultra-high energy cosmic rays by looking down. The \v{C}erenkov Telescope (CT) searches for neutrino signatures by looking toward Earth's limb. The two telescopes each have a 1 m diameter entrance pupil and segmented glass mirrors that collect light from extensive air showers at the PeV and EeV-scale. Here we describe the FT telescope optics together with the results of the FT field tests at the Utah Telescope Array (TA) site from August/September 2022. The FT recorded the night sky background, lasers, and artificial point sources. The field tests included an absolute photometric calibration of the FT telescope that is compared to a piece-wise laboratory calibration

Gamma-Ray Burst observations by the high-energy charged particle detector on board the CSES-01 satellite between 2019 and 2021

In this paper we report the detection of five strong Gamma-Ray Bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite (CSES-01), operational since 2018 on a Sun-synchronous polar orbit at a $\sim$ 507 km altitude and 97$^\circ$ inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3 - 100 MeV, protons in the range 30 - 300 MeV, and light nuclei in the range 30 - 300 MeV/n. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV - 50 MeV, even if with a moderate effective area above $\sim$ 5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterised by a fluence above $\sim$ 3 $\times$ 10$^{-5}$ erg cm$^{-2}$ in the energy interval 300 keV - 50 MeV, have been detected.Comment: Accepted for publication in The Astrophysical Journal (ApJ

Time Frame Selection for Optimal ISAR Image Reconstruction

In many application long recorded live ISAR data are used to obtain one or more ISAR images. In this paper we proposea technique for the automatic selection of the position and lenght of the time frame that provides the most focused ISAR images

Automatic Target Recognition on Terrestrial Vehicles based on Polarimetric ISAR Image and Model Matching

An Automatic Target Recognition (ATR) algorithm has recently been proposed that makes use of Polarimetric ISAR images and a Model Matching approach. In this paper, the authors propose a variation of such an approach that is suitable for ATR of terrestrial vehicles. The effectiveness of the proposed implementation is tested by means of real data acquired during a controlled turn-table experiment

Problems in the design of an HF-OTH skywave radar for the Mediterranean sea surveillance

Technical Report SKW1 Dept. of Information Engineering, Univ. of Pis

Automatic target recognition of terrestrial vehicles based on polarimetric ISAR image and model matching

An Automatic Target Recognition (ATR) algorithm has recently been proposed that makes use of Polarimetric ISAR images and a Model Matching approach. In this paper, the authors propose a variation of such an approach that is suitable for ATR of terrestrial vehicles. The effectiveness of the proposed implementation is tested by means of real data acquired during a controlled turn-table experiment.M. Martorella, E. Giusti, F. Berizzi, E. Dalle Mes