Research On Distributed Satellites SAR High Resolution Imaging Algorithms

Distributed Small Satellites Synthetic Aperture Radar (DSS SAR) systems hasbeen proposed recently in the field of Earth observation, this kind of SAR systemstake the formation flying satellites as its carriers. They possess several assets:multibaseline interferometry, ground moving target indication, multi-polarimetricimaging, high resolution imaging, wide-swath imaging. The DSS SAR orbit design,baseline analysis and design, high resolution imaging algorithm are studied in thisdissertation. The main works and innovations of this dissertation are as follows:1. The distributed satellites SAR orbit design method is investigated. A formationflying orbit design method based on satellites relative trajectories is proposed. Themathematic formula of formation flying orbit elements is derived. The ambiguityfunction of distributed satellites SAR is studied. The relation between satellitesformation configurations, number and ambiguity function is analyzed.2. The 3D characteristic of distributed satellites SAR baseline is investigated deeply.Mathematic mode is delivered; the baseline variety law in the distributed satellitesSAR cross track mode is given. The general distributed satellites SAR systembaseline design method which satisfies 3D imaging, MTI and high resolutionimaging is studied.3. The basic spectrum combination theory and realizing approach are deriveddeeply. The error and compensation method when range and azimuth spectrumcombination is carried through are analyzed first in this dissertation.4. The spatial filtering imaging mathematics mode is presented. Various spatial filtering imaging algorithms such as Matched Filtering, Maximum likelihood,Minimum Mean Square Error, Kalman Filtering are studied. The RLS spatialfiltering imaging algorithm is proposed. Through the spatial filtering imagingsimulation with different satellites formation configurations, the relationshipbetween satellites formation configurations and system resolution characteristic isstudied.5. The distributed satellites SAR high resolution imaging signal processing methodin along track mode is investigated. The Capon spectrum estimation method andmultilook processing are introduced into the along track mode distributedsatellites SAR signal processing. The approach restrains the azimuth Dopplerambiguity and noise of the system.