Conceptual Design and Image Motion Compensation Rate Analysis of Two-Axis Fast Steering Mirror for Dynamic Scan and Stare Imaging System

Abstract

In order to enable the aerial photoelectric equipment to realize wide-area reconnaissance and target surveillance at the same time, a dual-band dynamic scan and stare imaging system is proposed in this paper. The imaging system performs scanning and pointing through a two-axis gimbal, compensating the image motion caused by the aircraft and gimbal angular velocity and the aircraft liner velocity using two two-axis fast steering mirrors (FSMs). The composition and working principle of the dynamic scan and stare imaging system, the detailed scheme of the two-axis FSM and the image motion compensation (IMC) algorithm are introduced. Both the structure and the mirror of the FSM adopt aluminum alloys, and the flexible support structure is designed based on four cross-axis flexural hinges. The Root-Mean-Square (RMS) error of the mirror reaches 15.8 nm and the total weight of the FSM assembly is 510 g. The IMC rate equations of the two-axis FSM are established based on the coordinate transformation method. The effectiveness of the FSM and IMC algorithm is verified by the dynamic imaging test in the laboratory and flight test.

Analysis and Design of Infrared Search and Track System with Afocal Zoom Telescope

“…The method of homogeneous coordinate transformation is adopted in this section. Different from the model mentioned in the aforementioned papers, in which the optical system and its action matrix are considered as a whole in order to estimate the image motion of the IRST system [13][14][15][16], we divide the IRST optics into several parts to analyze the residual image wandering caused by projection transformation after image motion compensation by FSM. The position relationship and the imaging characteristics of each optical element are described by the matrix, and the transformation relationship from the object to the image is established by the matrix operation [14].…”

“…Kawachi pointed out the image motion issue of the oblique frame camera and provided a geometrical approximate analysis [13]. Wang and Yan introduced the coordinate transformation method to calculate the image motion in remote and aerospace camera systems [14]; this method has also been used by Chen et al and Sun et al to investigate the servo control system design [15,16]. Cook, Nouguès et al, Van et al and many other researchers proposed serval different kinds of imaging optical systems for IRST, but no descriptions of residual image wandering were given or discussed [17][18][19][20][21][22].…”

Coverage Path Planning with Adaptive Hyperbolic Grid for Step-Stare Imaging System

“…A feasible solution to achieve both high resolution and wide coverage is to employ an area-scan camera with a single lens in a step-stare manner [10][11][12][13]. The main concept is to utilize a two-axis gimbal assembly to steer narrow-FOV optics to rapidly scan the region of interest, capturing a sub-region once a step and, finally, stitching the images to create an equivalent wide-FOV picture [14][15][16][17]. Compared to other implementations, this mechanism allows for the design of optical systems with larger apertures and longer focal lengths while maintaining the same SWaP.…”

A fast steering mirror with ultra-low geometric tilt-to-length coupling noise for space-borne gravitational wave detection

“…Generally speaking, a FSM consists of a mirror, a mirror holder, a support plate, a base, an actuator (e.g. Piezo actuator, PZT), and a flexure hinge [10][11][12][13][14][15], as shown in figure 3(a). When the driver input line is displaced, the mirror will rotate around the center of the flexure hinge instead of the center of the mirror.…”