An Imaging Algorithm for Missile-borne SAR with Downward Movement Based on Azimuth Nonlinear Chirp Scaling

Zhou, Song; Bao, Min; Zhou, Peng; Xing, Mengdao; Bao, Zheng

doi:10.3724/sp.j.1146.2010.01124

Cited by 7 publications

(7 citation statements)

References 4 publications

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“…The conventional ESP [4] method does not focus on the accurate location of interference in the time domain but instead suppresses the interference within the whole pulse, which makes the uncontaminated signals within the pulse containing PRFI be decomposed. To solve this problem, this paper proposes an improved ESP-based interference suppression method, which only decomposes the data containing interference within the pulse with the help of accurate detection of the interference position.…”

Section: Sar Prfi Suppression Methods Based On the Improved Espmentioning

confidence: 99%

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SAR pulse radio frequency interference suppression based on modified eigen subspace projection

Liu,

Shu,

2023

International Conference on Remote Sensing, Mapping, and Geographic Systems (RSMG 2023)

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Synthetic aperture radar (SAR), as an active microwave remote sensor with high-resolution earth observation, is easily affected by radio frequency interference (RFI). Pulse radio frequency interference (PRFI), as a typical form of RFI, pollutes SAR raw data with bright stripes, which increases the difficulty of SAR image interpretation. However, the conventional eigen subspace projection (ESP) method decomposes the whole pulse into the interferences and the useful signals, resulting in the loss of useful signals in the non-interference positions with the pulse. To solve this problem, this paper proposes an improved SAR PRFI suppression method based on ESP. Firstly, the receiving pulses containing PRFI are detected and the specific position of PRFI in the pulse are determined by eigenvalue decomposition and energy accumulation in timefrequency domain, respectively. Secondly, the PRFI signal is separated from the useful signal by applying the ESP method only to the data where the PRFI is located. Finally, the PRFI signal projected by ESP is eliminated from the raw data. Simulation results shown that the proposed method can better protected useful signals and improve SAR image quality compared with conventional methods.

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Section: Sar Prfi Suppression Methods Based On the Improved Espmentioning

confidence: 99%

“…1) Detecting the pulses with PRFI. Obtain the maximum eigenvalue sequence of all pulse based on eigenvalue decomposition [4] (EVD), which is denoted as…”

Section: Sar Prfi Suppression Methods Based On the Improved Espmentioning

confidence: 99%

SAR pulse radio frequency interference suppression based on modified eigen subspace projection

Liu,

Shu,

2023

International Conference on Remote Sensing, Mapping, and Geographic Systems (RSMG 2023)

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“…With current hardware technology, the antenna and the digital processor can be compacted into a very small and cheap flying platform for QMUAV SAR imaging. Being equipped with a SAR sensor on the UAV, high-resolution microwave images of the observed scene can be obtained to enhance its sensing capability under various environmental conditions (Coker and Tewfik, 2011;Zeng et al, 2015;Yang et al, 2015;Sun et al, 2013;Zhou et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Motion Error Compensation for Quad-rotor Miniature Unmanned Aerial Vehicle SAR Imaging

Zhou

Yang

et al. 2016

Proceedings of the 13th International Joint Conference on E-Business and Telecommunications

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Quad-rotor miniature unmanned aerial vehicle (QMUAV) synthetic aperture radar (SAR) is an ultra-small airborne SAR system. Because of lowing flying altitude and small size constraints, the motion errors of QMUAV-SAR are very complicated which introduces difficulty to the QMUAV-SAR imaging processing. To deal with this problem, an effective motion compensation approach for QMUAV-SAR is proposed. By establishing the relationship between the motion errors and the Doppler parameters of SAR echoes, the motion errors of QMUAV platform are extracted from the estimated Doppler rates. After the majority of the motion error being properly compensated, phase gradient autofocusing (PGA) is employed to estimate and compensate the residual phase errors to further improve the focusing quality of the SAR image. Experimental results are provided and the image quality is evaluated to demonstrate the ability of achieving well focused image and high spacial resolutions of the proposed method.

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“…[9] refines the signal model of classic CS algorithm to implement precisely imaging in high squint. [10] improves the nonlinear chirp scaling algorithm to correct the range migration in the 2-dimenstion frequency and to compensate the azimuth variation of Doppler parameters. [11] corrects the range walk firstly and then employs the modified azimuth nonlinear chirp scaling to overcome the parameters variation.…”

Section: Introductionmentioning

confidence: 99%

A Variable PRF Imaging Method for High Squint Diving Sar

Xu¹,

Gao²,

Li³

2013

PIER

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Abstract-The high squint diving SAR is widely used to provide the information in advance. Large squint angle deduces the deeper coupling of range and azimuth of SAR echoes which makes SAR imaging more difficult. Especially, the large range migration of the deep couple heavily burdens the imaging processing time and storage units. The diving motion of platform worsens the situation. This paper proposes the varied azimuth sample frequency (Pulse Repeat Frequency, PRF) to implement the high squint diving SAR imaging. Based on the signal model of the diving squint SAR, it is analyzed that the range walk is the prominent component of range migration in the high squint SAR. The varied PRF imaging method dramatically decreases the range walk of echoes by shifting the beginning position of transmitted pulses and received echoes and the shift is implemented by the PRF variation. Then the range migration is decreased and the couple of range and azimuth of SAR echoes is reduced. The PRF variation law is deduced and the applicable condition of varied PRF is presented. The simulation results show that the variable PRF method is efficient to reduce range walk of echoes. Comparison to the traditional constant PRF, the novel variable PRF method for high squint needs less storage and less time expense, which is helpful to real time SAR imaging. The non-uniform FFT can be used for the azimuth compressing of the variable PRF SAR. It will simplify the implementation of the variable PRF SAR imaging.

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An Imaging Algorithm for Missile-borne SAR with Downward Movement Based on Azimuth Nonlinear Chirp Scaling

Cited by 7 publications

References 4 publications

SAR pulse radio frequency interference suppression based on modified eigen subspace projection

SAR pulse radio frequency interference suppression based on modified eigen subspace projection

Motion Error Compensation for Quad-rotor Miniature Unmanned Aerial Vehicle SAR Imaging

A Variable PRF Imaging Method for High Squint Diving Sar

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