A fast Fourier transform (FFT)-based along track interferometry (ATI) approach to SAR-based ground moving target indication (GMTI)

2014 ◽  
Author(s):  
Daniel D. Thomas ◽  
Yuhong Zhang
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Moving Target ◽  
Along Track ◽  
Ground Moving Target Indication

scholarly journals Ship Velocity Estimation in Airborne Along-Track Interferometric SAR Imagery Based on the Fractional Fourier Transform

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chao Chen ◽  
Yan Li ◽  
Kuihua Huang ◽  
Yonghong Long ◽  
Linlin Zhang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fractional Fourier Transform ◽  
Velocity Estimation ◽  
Moving Target ◽  
Chirp Rate ◽  
Target Imaging ◽  
Moving Target Imaging ◽  
Sar Imagery ◽  
Interferometric Sar ◽  
Along Track

Synthetic aperture radar (SAR) was originally exploited to image stationary scenes. However, it is important to derive target information of velocity for many applications. The fractional Fourier transform (FrFT) is a generalization of the classical Fourier transform and is well-known as a useful tool to estimate the chirp rate of linear frequency-modulated (LFM) signals. Motion compensation is critical to moving target imaging. It is difficult for us to obtain the actual motion parameters in real scenarios. Based on the moving target echo model in airborne along-track interferometric SAR (ATI-SAR) and expression of the ATI phase, a method is proposed to estimate the ship velocity by combining the ATI phase with FrFT. First, we use the FrFT to evaluate the chirp rate of the moving target echo. Then, we construct an equation to estimate the ship velocity using the chirp rate estimation, peak response time, and ATI phase. Finally, the simulation experiments are used to validate the effectiveness of the proposed method.

A Direct Approach to Separate Forward-Scattered Waves from the Direct Blast in Doppler Domain for Forward-Scattering Detection

2018 ◽  
Vol 26 (01) ◽  
pp. 1750036 ◽  
Author(s):  
Chuanlin He ◽  
Kunde Yang ◽  
Yuanliang Ma ◽  
Bo Lei
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Kinetic Characteristic ◽  
Forward Scattering ◽  
Direct Approach ◽  
Moving Target ◽  
Tank Experiment ◽  
Doppler Analysis

Forward-scattered waves are often interfered with and overwhelmed by direct blasts when a submerged target crosses the source–receiver line. The approach named low Doppler analysis and recording gram (LODARGRAM) is developed to separate forward-scattered waves from direct blasts in the Doppler domain. This separation, which is based on the kinetic characteristic of the target and the procedure, is conducted using a sliding Blackman window combined with fast Fourier transform. The concept along with its application is validated using the data collected in a tank experiment. The moving target is recognized and identified by a tilt striation on LODARGRAM. Limitations of the LODARGRAM approach are also discussed.

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