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The tropospheric time variance within the ultra-long integration time of Geosynchronous Synthetic Aperture Radar (GEO SAR) needs to be considered for imaging. Meanwhile, because of the curved trajectory and the very complex geometry relationship between the target position and the satellite, the traditional analysis method of troposphere on low earth orbit (LEO) SAR imaging will no longer be suitable...
Owing to the curved track, geosynchronous synthetic aperture radar (GEO SAR) can obtain a height resolution. An accurate expression of the height resolution is derived for GEO SAR based on the generalised ambiguity function and the Doppler history difference between two adjacent targets at different heights. It is found that the height resolution is introduced by the accelerated motion or the curved...
The background ionosphere time variance within the extremely long integration time of Geosynchronous Synthetic Aperture Radar (GEO SAR) needs to be considered for GEO SAR focusing. Meanwhile, because of the curved trajectory and the very complex geometry relationship between satellite motion and earth rotation, the traditional analysis method of background ionosphere on LEO SAR imaging will no longer...
The Doppler rate of geosynchronous synthetic aperture radar (GEO SAR) is zero at some orbital positions due to their high altitude. Also, the Doppler frequency varies along the range direction in the squint mode which is widely used in GEO SAR. The above-mentioned Doppler characteristics have serious effects on the calculation of geo-location error, which are not considered in the conventional model...
Inclined geosynchronous Earth orbit synthetic aperture radar (GEO SAR) is seriously affected by Earth rotation because of its identical angular velocity with the Earth rotation. Therefore, the composition motion of GEO SAR and the illuminated target is extremely complicated because of the inclined orbit geometry. Hence the analysis methods of stripmap mode are no longer suitable for GEO SAR. The classical...
Velocity is an essential parameter in Synthetic Aperture Radar (SAR) system design. The conventional velocity calculation model is not applicable for Geosynchronous Earth Orbit Synthetic Aperture Radar (GEO SAR), so an improved velocity calculation model is proposed in this paper. Firstly, this paper analyses the type of satellite velocity which could be adopted in Doppler parameter calculation. Secondly,...
In geosynchronous (GEO) synthetic aperture radar (SAR), the synthetic aperture time (SAT) is very long and the trajectory mode should be considered as curve. This paper mainly analyzes the impacts of target azimuth position displacement on GEO SAR image formation. Because GEO SAR imaging need be based on the curved trajectory, targets' azimuth position displacement on GEO SAR image formation can affect...
The characteristics of geosynchronous Earth orbit synthetic aperture radar (GEO SAR) are affected significantly by Earth rotation. This paper first proposes a series of analytical methods of satellite motion parameters in arbitrary earth orbit height under the Satellite local Coordinate System. Then several calculation formulas of SAR system parameters, such as SAR Quality, are modified and the potential...
In this paper, considering the relative motion between satellite and earth during signal propagation time, the accurate analysis method for propagation slant range is presented in geosynchronous SAR. Furthermore, the difference between accurate analysis method and `Stop-and-Go' assumption is analytically obtained. Meanwhile based on the derived accurate slant range model, it is found that the corresponding...
The key problem of the imaging processing in geosynchronous earth orbit (GEO) SAR system is the space-variance of the Doppler parameters, which will result in the defocus of the SAR image with classical imaging algorithm. In this paper, a Modified Range Migration Algorithm (RMA) is proposed to overcome the space-variance of Doppler parameters by compensating the velocity change along the location...
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