Fast and Efficient Correction of Ground Moving Targets in a Synthetic Aperture Radar, Single-Look Complex Image

Abstract

Ground moving targets distort normally-focused synthetic aperture radar (SAR) images. Since most high-resolution SAR data providers only offer single-look complex (SLC) data rather than raw signals to general users, they need to apply a simple and efficient residual SAR focusing to SLC data containing moving targets. This paper presents an efficient and effective SAR residual focusing method that is practically applicable to SLC data. The residual Doppler spectrum of the moving target is derived from a general SAR configuration and normal SAR focusing. The processing steps are simple and straightforward, with a limited size of the processing window, e.g., 64 × 64. Application results using simulation data and actual TerraSAR-X SLC data with a speed-controlled vehicle demonstrate the effectiveness of the method, which particularly improves the −3 dB width, integrated sidelobe ratio, and symmetry of the reconstructed signals. In particular, the azimuthal symmetry becomes seriously distorted when the target speed is higher than 8 m/s (or 28.8 km/h), and the symmetry is well recovered by the proposed method.

Acceleration Compensation for Estimation of Along-Track Velocity of Ground Moving Target from Single-Channel SAR SLC Data

“…However, the velocity variation in ground moving targets is often irregular or discontinuous, rather than exhibiting a linear increase or decrease. Instead of a linear variation in velocity with a constant acceleration, here we consider a general velocity variation model such that v y (t) = v y,0 + δv y (t) (18) where δv y (t) is the time-varying deviation from mean velocity v y,0 . This velocity model accommodates the local or instantaneous variation in target velocity during the antenna integration time, regardless of whether the variation is linear.…”

Two-Dimensional Ship Velocity Estimation Based on KOMPSAT-5 Synthetic Aperture Radar Data

“…A point target in the SLC data is represented by the range and azimuth compressed signals. A range and azimuth compressed point moving target in the SAR SLC data can be described by a frequency spectrum S MT ( f , f τ ) in a two-dimensional frequency domain as follows [11]:…”

Doppler Frequency Estimation of Point Targets in the Single-Channel SAR Image by Linear Least Squares

“…Provided that a point target is focused with a residual Doppler frequency, f d , a point target in a single-look complex SAR image can be described by a simple model such as Reference [21],…”

“…Thus, a precise estimation of the Doppler parameters is the key to the detection and velocity retrieval of ground moving targets by single-channel SAR observation. An efficient residual focusing is also possible once the two velocity components are obtained [21]. The main goal of this paper is to propose a high-performance method for accurate estimation of the residual Doppler frequency and consequently, the range velocity component of the point targets from the single-channel SAR focused single-look complex (SLC) data.…”