scholarly journals Robust Space Time Adaptive Processing Methods for Synthetic Aperture Radar

2020 ◽  
Vol 10 (10) ◽  
pp. 3609
Author(s):  
Shijian Shen ◽  
Lan Tang ◽  
Xin Nie ◽  
Yechao Bai ◽  
Xinggan Zhang ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Interference Cancellation ◽  
Model Simulation ◽  
Space Time ◽  
Synthetic Aperture ◽  
Adaptive Processing ◽  
Slow Time ◽  
Space Time Adaptive Processing ◽  
Data Constraints ◽  
Aperture Radar

This paper proposes two modified space time adaptive processing (STAP) methods based on piecewise sub-apertures and data constraints for non-stationary interference cancellation in synthetic aperture radar (SAR) applications. In these methods, the entire synthetic aperture time is divided into several sub-apertures so that the interference can be considered as stationary in each sub-aperture. At the same time, the consistency of the echo phase in the slow time domain is preserved by the data constraint to ensure the null depth of the antenna pattern for non-stationary interference cancellation and the performance of azimuth focusing in SAR. The proposed algorithms are validated through the model simulation and measured data.

Coexistence of Atmospheric Gravity Waves and Boundary Layer Rolls Observed by SAR*

2013 ◽  
Vol 70 (11) ◽  
pp. 3448-3459 ◽  
Author(s):  
Xiaofeng Li ◽  
Weizhong Zheng ◽  
Xiaofeng Yang ◽  
Jun A. Zhang ◽  
William G. Pichel ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Synthetic Aperture Radar ◽  
Gravity Waves ◽  
Dynamic Instability ◽  
Model Simulation ◽  
The Yellow Sea ◽  
Synthetic Aperture ◽  
Atmospheric Gravity Waves ◽  
Atmospheric Gravity ◽  
Aperture Radar

Abstract Both atmospheric gravity waves (AGW) and marine atmospheric boundary layer (MABL) rolls are simultaneously observed on an Environmental Satellite (Envisat) advanced synthetic aperture radar (ASAR) image acquired along the China coast on 22 May 2005. The synthetic aperture radar (SAR) image covers about 400 km × 400 km of a coastal area of the Yellow Sea. The sea surface imprints of AGW show the patterns of both a transverse wave along the coastal plain and a diverging wave in the lee of Mount Laoshan (1133-m peak), which indicate that terrain forcing affects the formation of AGW. The AGW have a wavelength of 8–10 km and extend about 100 km offshore. Model simulation shows that these waves have an amplitude over 3 km. Finer-scale (~2 km) brushlike roughness features perpendicular to the coast are also observed, and they are interpreted as MABL rolls. The FFT analysis shows that the roll wavelengths vary spatially. The two-way interactive, triply nested grid (9–3–1 km) Weather Research and Forecasting Model (WRF) simulation reproduces AGW-generated wind perturbations that are in phase at all levels, reaching up to the 700-hPa level for the diverging AGW and the 900-hPa level for the transverse AGW. The WRF simulation also reveals that dynamic instability, rather than thermodynamic instability, is the cause for the MABL roll generation. Differences in atmospheric inflection-point level and instability at different locations are reasons why the roll wavelengths vary spatially.

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