A velocity estimation method of moving target for SAR high-resoluton wide-swath mode

Abstract

This manuscript focuses on velocity estimation for synthetic aperture radar (SAR) in high-resolution wide-swath mode. HRWS mode is proposed to overcome the system-inherent limitation, which allows for collecting additional samples under relatively low PRF. Unlike the previous work of SAR ground moving target indication (GMTI) in single channel and multiple channels, the velocity estimation in HRWS GMTI would face two inherent unavoidable problems: the under-sampled data in single channel and non-uniform samples in azimuth. The proposed method is effective, accurate and efficient under these two problems. Some relevant simulations are shown to validate the proposed scheme.

A Simultaneous Imaging Scheme of Stationary Clutter and Moving Targets for Maritime Scenarios with the First Chinese Dual-Channel Spaceborne SAR Sensor

“…Some methods work well for the conventional multichannel SAR system when the signals of each channel are over-sampled in the image domain [23,24]. For the HRWS SAR system, methods carried out in the signal domain to estimate velocity is proposed in References [25,26]. The method described in Reference [25] estimates the velocity by estimating the direction-of-arrival (DOA) of the signal.…”

“…The method described in Reference [25] estimates the velocity by estimating the direction-of-arrival (DOA) of the signal. A velocity estimation algorithm proposed in Reference [26] is based on the analysis of signal subspace and noise subspace, but the method suffers from the limitation of at least one redundant channel, which means the number of RX antennas should be greater than the Doppler ambiguity number. In addition, a novel algorithm for velocity estimation conducted in the echo domain is proposed in Reference [10], which applies the maximum likelihood (ML) method to estimate the cone angle as well as the radial velocity.…”

An ML-Based Radial Velocity Estimation Algorithm for Moving Targets in Spaceborne High-Resolution and Wide-Swath SAR Systems

“…The difference is the criterion they are based on. The proposed ML-based algorithm has lower complexity than the iterative approaches in [9][10][11], which need imaging for each possible velocity during the iteration. Moreover, this algorithm can estimate velocities of multiple moving targets as it does not need a large number of Doppler bins, as long as the number is larger than that of the receive channels.…”

“…Moving target indication and imaging is one of the primary applications of spaceborne HRWS SAR systems, especially for ocean remote sensing [2,3]. Estimation of the target's velocity is crucial for target relocation, focused imaging and false target suppression [5][6][7][8][9][10][11][12][13][14][15].…”

“…However, without analyzing the efficiency or considering the sea clutter, the analysis is not comprehensive. In [9][10][11], the imagery quality of the moving target is weighed by some criterion, and the radial velocity is estimated by searching for the value which optimizes the imagery quality. These approaches need iteration, thus guaranteeing the accuracy with the sacrifice of efficiency.…”