[Show abstract][Hide abstract] ABSTRACT: This paper presents a new phase unwrapping algorithm based on the unscented Kalman filter (UKF) for synthetic aperture radar (SAR) interferometry. This method is the result of combining an UKF with path-following strategy and an omni-directional local phase slope estimator. This technique performs simultaneously noise filtering and phase unwrapping along the high-quality region to the low-quality region, which is also able to avoid going directly through the noisy regions. In addition, phase slope is estimated directly from the sample frequency spectrum of the complex interferogram, by which the underestimation of phase slope is overcome. Simulation and real data processing results validate the effectiveness of the proposed method, and show a significant improvement with respect to the extended Kalman filtering (EKF) algorithm and some conventional phase unwrapping algorithms in some situations.
Preview · Article · Jun 2011 · Journal of Systems Engineering and Electronics
[Show abstract][Hide abstract] ABSTRACT: This paper presents a phase unwrapping algorithm based on the extended kalman filter (EKF) for multi-baseline SAR interferometry. This algorithm achieves simultaneously noise filtering and phase unwrapping by combining an EKF with a conventional path-tracing strategy. The simulation data processing results validate the effectiveness of proposed method, and show a significant improvement with respect to some conventional algorithms in some situations.
[Show abstract][Hide abstract] ABSTRACT: This paper addresses impact of frequency source noise in terahertz (THz) moving objection detection systems. Oscillator noise deserves special attention in terahertz (THz) moving objection detection systems since phase jitter in high-power THz frequency source is relatively serious. Such phase jitter (noise) will lead to a few serious problems and seriously affect performance of THz moving object detection systems. In this paper, quantitative estimates of impact of frequency source noise in THz moving target detection systems are derived analytically and requirement for coherent accumulated time limited by frequency source phase noise is deduced based on the second-order statistics characteristic of the oscillator phase noise. This research results could further consummate THz theory system and provide theory basis for the system design.
Preview · Article · Jul 2009 · Proceedings of SPIE - The International Society for Optical Engineering
[Show abstract][Hide abstract] ABSTRACT: Doppler Beam Sharpening (DBS) technique is one of high-resolution radar imaging technique. DBS images are widely used in tactical reconnaissance, terrain matching and navigation, as well as target identification, etc. Range walking correction technique and azimuth dechirping technique can increase the coherent accumulated time of DBS imaging system, which provides greater space for high-resolution DBS Imaging. However, the resolution of DBS images will be limited by frequency source phase noise. This study addresses the effects of frequency source phase noise on the high-resolution DBS imaging. Quantitative estimates are derived analytically based on the second-order statistics characteristic of oscillator phase noise. The research results could further consummate high-resolution DBS imaging theory and provide theory basis for DBS imaging system design.
Preview · Article · Apr 2009 · Information Technology Journal