ARTICLE | doi:10.20944/preprints201905.0260.v1
Subject: Earth Sciences, Oceanography Keywords: Synthetic aperture radar (SAR); along-track interferometry (ATI); sub-pixel offset tracking (sPOT); COSMO-SkyMed (CSK); staring spotlight (ST); micro-motion (m-m); vibrations; frequency modes
Online: 21 May 2019 (11:33:59 CEST)
This research aims to estimate the micro-motion (m-m) of ships. The problem of motion and m-m detection of targets is usually solved using synthetic aperture radar (SAR) along-track interferometry (ATI) which is observed employing two radars spatially distanced by a baseline extended in the azimuth direction. This paper is proposing a new approach where the m-m estimation of ships, occupying thousands of pixels, is measured processing the information given by sub-pixel tracking generated during the coregistration process of several re-synthesized time-domain and overlapped sub-apertures. The SAR products are generated splitting the raw data, according to a small-temporal baseline strategy, observed by one single wide-band staring spotlight (ST) SAR image. The predominant vibrational modes of different ships are estimated and results are promising to extend this application in performing surveillance also of land-based industries activities. Experiments are performed processing one ST SAR image observed by the COSMO-SkyMed satellite system.
ARTICLE | doi:10.20944/preprints202208.0329.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Synthetic Aperture Radar; Doppler frequencies; multi-chromatic analysis; micro-motion; Pyramid of Khnum-Khufu; sonic images
Online: 18 August 2022 (03:45:58 CEST)
A problem with synthetic aperture radar (SAR) is that, due to the poor penetrating action of electromagnetic waves inside solid bodies, the capability to observe inside distributed targets is precluded. Under these conditions, imaging action is provided only on the surface of distributed targets. The present work describes an imaging method based on the analysis of micro-movements on the Khnum-Khufu Pyramid, which are usually generated by background seismic waves. The results obtained prove to be very promising, as high-resolution full 3D tomographic imaging of the pyramid's interior and subsurface was achieved. Khnum-Khufu becomes transparent like a crystal when observed in the micro-movement domain. Based on this novelty, we have completely reconstructed internal objects, observing and measuring structures that have never been discovered before. The experimental results are estimated by processing series of SAR images from the second-generation Italian COSMO-SkyMed satellite system, demonstrating the effectiveness of the proposed method.