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Fast Moving Target Imaging Algorithm Based on Hough Transform and Third-Order PFT

Principle of the Proposed Algorithm.

In conventional GMTIm algorithms [8-10], the basic processing steps: firstly, the RCMC is proceeded to compress the energy of the target into a single range gate; secondly, the parameters of the moving target is estimated by using the time-frequency analysis algorithms. Keystone transform is able to correct the range walk without prior knowledge of the Doppler centroid. However, in the case of the fast moving target, Keystone transform is not able to correct the range walk without the Doppler ambiguity number. Therefore, in the case of the fast moving target imaging, the Doppler ambiguity must be taken into consideration.

In this section, a novel algorithm is proposed to focus the moving targets with fast cross-track velocities. After range compression and range curve correction, we utilize Hough transform to estimate the slope of the range walk trajectory of the moving target. With Hough transform, the additional range walk can be accurately corrected regardless of the Doppler ambiguity, and the cross-track velocity can be estimated. Then, we adopt PFT to estimate the second- and third-order Doppler parameters of the moving target. The imaging resolution of the moving target is improved after the third-order phase error compensation, and the motion parameters, including the cross-track acceleration, can be accurately estimated.

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Fast Moving Target Indication and Imaging in Stripmap SAR
Abstract This chapter mainly discusses the GMTI and GMTIm algorithms in stripmap SAR/GMTI mode. The signal model of fast moving targets in stripmap SAR/GMTI mode is established, and the impacts of fast cross-track velocities on the Doppler ambiguity and higher order azimuth phase are analyzed....
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Echo Model of Fast Moving Target
The echo model of fast moving target is established in this section. No matter what the motion parameters of the target are, the geometry of the moving target in broadside SAR is unchanged. Therefore, the echo model is established based on Figs. 2.2 and 2.3. According to Eq. 2.3.4, cross-track velocity,...
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Along-Track Moving Target Indication Algorithm in FMCW SAR
The geometry of an along-track moving target in a FMCW SAR system is illustrated in Fig. 5.10. In Fig. 5.10, the instantaneous slant range can be expressed as Fig. 5.10 Geometry of an along-track moving target in FMCW SAR Substitute Eq. 5.4.4 into Eq. 5.2.7, the echo of the along-track moving...
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
SAR Ground Moving Target Indication and Imaging Theory
Abstract This chapter mainly introduces the basic principles of SAR imaging, signal model, GMTI and GMTIm algorithms. The geometries of stationary and moving targets are established, and the characters of their echoes are analyzed. Based on the analysis, three classical single-channel GMTI algorithms...
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Principle of the Proposed Algorithm
In this section, the principle and processing steps of the proposed algorithm are introduced. The aim of the implementation of CZT is to avoid the use of Doppler centroid estimation algorithms. Thus, the processing of DBS algorithm is simplified, and Doppler centroid estimation error is circumvented....
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Principle of Existing GMTI Algorithms
All existing GMTI algorithms use the Doppler characters of moving targets and their differences from those of the stationary targets to accomplish the target detection. There are mainly two parts in GMTI algorithms: clutter suppression and CFAR detection. Principle of Single-Antenna GMTI Algorithms...
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Principle of Single-Antenna GMTI Algorithms
Different GMTI algorithms use different methods to suppress the clutter. By suppressing the clutter, the spectra of moving targets can be separated from the clutter, and the SCR is increased. (a) Spectrum filtering algorithm According to the analysis in Sect. 2.3.2, a Doppler centroid shift is...
(Study on Ground Moving Target Indication and Imaging Technique of Airborne SAR)
Proposed Algorithm
For compression and decompression of images the basic steps are [22,25,26,27,28]: a. Input image is taken from the source/scanner. b. Image decomposition is performed. c. Compressed image is created after performing certain steps. d. Denoising the image by utilizing threshold value. e. For input image...
(Artificial Intelligence and Machine Learning in 2D/3D Medical Image Processing)