Geosynchronous SAR: System and Signal Processing

Li, Teng; Hu, Cheng; Ding, Zegang; Dong, Xichao; Tian, Weiming; Zeng, Tao

doi:10.1007/978-981-10-7254-3

Cited by 25 publications

(27 citation statements)

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“…where is the GEO-SAR range, the total losses, λ is the wavelength and is the mean antenna directivity at the beam center (see Figure 2). The evaluation of the signal to interference ratio (SIR) can carried out by comparing the backscattered echo power, as from Radar Equation [1][2][3][4][5][6][7], to the total RFI power. We assume that the GEO and LEO-SARs have uniform illumination and that transmit for all time the mean power, the product of peak power and the duty cycle.…”

Section: Leo-to-geo Rfi Evaluationmentioning

confidence: 99%

“…• is the total LEO-SAR transmitted power; • , , , is the bistatic scatter coefficient from the i-th LEO-SAR direction, defined by incidence and azimuth angles , to the GEO-SAR one, defined by , ; • is the range from LEO-SAR scene center to GEO-SAR; • , is the GEO-SAR antenna directivity to the LEO-SAR beam center, see Figure 2. Note that we do assume the same losses in both GEO, in (1) and LEO, in (2), that is equivalent to ignore them as for the signal-to-interference ratio (SIR).…”

Section: Leo-to-geo Rfi Evaluationmentioning

confidence: 99%

“…Geosynchronous synthetic aperture radar (SAR) are acquiring momentum due to their capability to perform imaging over wide areas with a revisit otherwise impossible with low Earth orbiting (LEO) or medium Earth orbiting (MEO) SAR [1][2][3][4]. In particular, the concept of a geostationary orbiting SAR, that should fulfill ITU requirements allowing a slight, non-zero eccentricity orbit to provide a synthetic aperture, is quite attractive for their capability of near-continuous imaging.…”

Section: Introductionmentioning

confidence: 99%

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LEO to GEO-SAR Interferences: Modelling and Performance Evaluation

et al. 2019

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This paper proposes a statistical model to evaluate the impact of the signal backscattered by low Earth orbiting (LEO) synthetic aperture radar (SAR) and received by GEO-stationary orbiting SAR. The model properly accounts for the bistatic backscatter, the number of LEO-SAR satellites and their duty cycles. The presence of many sun-synchronous, dawn-dusk satellites creates a 24 h periodic pattern in interference that should be considered in the acquisition plan of future geostationary SAR. The model, implemented by a numerical simulator, allows also the prediction of performance in future scenarios of many LEO-SAR. Examples and evaluations are made here for X band.

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Section: Leo-to-geo Rfi Evaluationmentioning

confidence: 99%

Section: Leo-to-geo Rfi Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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LEO to GEO-SAR Interferences: Modelling and Performance Evaluation

et al. 2019

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“…Geosynchronous synthetic aperture radar (GEO SAR) is a spaceborne SAR system operating at geosynchronous orbit with a height of about 36,000 km [1,2]. Compared with the traditional low Earth orbit SAR (LEO SAR), GEO SAR has the advantages of a short revisit period (several hours to one day) and extensive coverage (imaging swath wider than 2000 km).…”

Section: Introductionmentioning

confidence: 99%

“…[4], so it has significant application potential for disaster prevention and mitigation, including flood disaster, geological disaster, etc. [1,[5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Formation Design for Single-Pass GEO InSAR Considering Earth Rotation Based on Coordinate Rotational Transformation

Chen

Dong

et al. 2020

Remote Sensing

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The single-pass geosynchronous synthetic aperture radar interferometry (GEO InSAR) adopts the formation of a slave satellite accompanying the master satellite, which can reduce the temporal decorrelation caused by atmospheric disturbance and observation time gap between repeated tracks. Current formation design methods for spaceborne SAR are based on the Relative Motion Equation (RME) in the Earth-Centered-Inertial (ECI) coordinate system (referred to as ECI-RME). Since the Earth rotation is not taken into account, the methods will lead to a significant error for the baseline calculation while applied to formation design for GEO InSAR. In this paper, a formation design method for single-pass GEO InSAR based on Coordinate Rotational Transformation (CRT) is proposed. Through CRT, the RME in Earth-Centered-Earth-Fixed (ECEF) coordinate system (referred to as ECEF-RME) is derived. The ECEF-RME can be used to describe the accurate baseline of close-flying satellites for different orbital altitudes, but not limited to geosynchronous orbit. Aiming at the problem that ECEF-RME does not have a regular geometry as ECI-RME does, a numerical formation design method based on the minimum baseline error criterion is proposed. Then, an analytical formation design method is proposed for GEO InSAR, based on the Minimum Along-track Baseline Criterion (MABC) subject to a fixed root mean square of the perpendicular baseline. Simulation results verify the validity of the ECEF-RME and the analytical formation design method. The simulation results also show that the proposed method can help alleviate the atmospheric phase impacts and improve the retrieval accuracy of the digital elevation model (DEM) compared with the ECI-RME-based approach.The performance of InSAR and TomoSAR based on monostatic GEO SAR significantly degrades due to temporal decorrelation (caused by the scene scattering fluctuation during the observation time gap between repeated tracks) and atmospheric disturbance. Similar to LEO SAR [8], we can use the formation GEO SAR to form a real-time baseline to improve interferometry performance [9,10], realizing single-pass GEO InSAR. Additionally, multiple phase centers can be generated in GEO SAR formation, and a flexible baseline configuration can enrich the functions.The primary task of SAR formation is to design the satellite orbital elements to obtain a reasonable formation configuration and then meet the application performance requirements. The formation design of LEO SAR has been adequately studied, and a very mature solution has been found. A very typical method is to describe the geometry of the formation using the Relative Motion Equation (RME) based on the difference between the master satellite's and slave satellite's orbital elements, and combining the mission requirements to design the satellite's orbital elements [11].The theoretical study of the Relative Motion Equation has gone through three stages. The earliest form of RME, which was used to complete spacecraft rendezvous and docking tasks [12], was obtain...

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