Effect of 6-DOF Oscillation of Ship Target on SAR Imaging

Abstract

Ship targets are high-value military and civilian targets with broad application prospects. However, the precise focusing of ships is still a difficult issue because of their complicated six-degree-of-freedom motions on the sea surface. This paper focused on investigating the effect of ship six-degree-of-freedom oscillation on Synthetic Aperture Radar imaging. Firstly, based on the six-degree-of-freedom motions, the accurate range models for ship linear oscillation and angular oscillation were built, and the superiority was verified by comparing them with the models described in published literature. Secondly, we used the Taylor formula and Bessel function to expand the phase error introduced by ship oscillation, then their effects on imaging were further analyzed. Finally, based on the measured ship attitude data, we generated the semi-physical echoes of the oscillatory ship to validate the analysis throughout this article. Based on the proposed range model, we also made some tentative on the phase compensation method by fitting ship attitude angles with multiple sinusoidal functions.

3D geometry‐based UAV to vehicle multiple‐input multiple‐output channel model incorporating Unmanned aerial vehicle heaving motion

“…While the UAV's position and orientation in the world coordinate system xyz may change as it rotates or changes orientation, its position and orientation in the fixed coordinate system will remain constant, which is depicted in Figure 3. Thus, the UAV is moving through the xy plane, so the pitch and yaw angle coordinates will be The UAV with the world coordinate systems can be transformed into the proposed model [27] as xðtÞ yðtÞ zðtÞ…”

“…By substituting the values of the transceiver location vector, which are discussed in Equations ( 26) and (27), and the distance between the UAV and the reflection point, we derived Equation (32). The time variants θ…”

“…The UAV with the world coordinate systems can be transformed into the proposed model [27] as $$$\left[\begin{array}{@{}c@{}}\hfill x(t)\hfill \\ \hfill y(t)\hfill \\ \hfill z(t)\hfill \end{array}\right]=\mathbf{R}\mathbf{o}{\mathbf{t}}_{\mathbf{u}}(t)\left[\begin{array}{@{}c@{}}\hfill {x}^{\prime }+{\Delta }X\hfill \\ \hfill {y}^{\prime }+{\Delta }Y\hfill \\ \hfill {z}^{\prime }+{\Delta }Z\hfill \end{array}\right]$$$ where Δ X and Δ Y define the x and y ‐axis random displacement, which is caused by the UAV linear oscillation, where the fixed coordinate system can be defined as x ′ y ′ z ′. By substituting the values of the roll angle, pitch angle, and yaw angle, which are mentioned in Equations (), (), and (), Equation () is derived from these equations, which is the transformation matrix of Equation ().…”

A novel micro-motion feature extraction and estimation method for multicomponent signal

“…In recent years, the enormous progress in the maritime career makes it significant to observe and monitor the marine environment. However, because of the oceanic waves and other interference factors, ship targets not only sail under their power, but with complex non-linear motion, which can be divided into linear motion (sway, surge, and heave) and rotation motion [1] [2] (roll, pitch, and yaw). As a result of the micro-motion (MM), the SAR images are defocused.…”

The Staring Mode Properties and Performance of Geo-SAR Satellite with Reflector Antenna

“…It has the advantages of short revisit cycle, fast maneuver monitoring capability, large imaging width, and long staring time. Therefore, it has a wide application prospection in large-scale disaster monitoring, marine observation, geological mapping, and so on [2][3][4][5][6][7][8]. The China Academy of Space Technology(CAST) is currently developing Geo-SAR for disaster monitoring.…”