Research On Testing Technique Of Aiming Deviation Of Laser, Visible-light And Infrared-light Three-optical Axes

In recent years, with the continuous development of photoelectric technology, more and more modern photoelectric equipment with tracking and measuring tend to contain the multi-optical channels of the laser, television, and infrared, so the research of photoelectric systems with multi-band and multi-channel will become the development trend of photoelectric devices. If multi-optical system simultaneously measures and aims at the same target, the parallel problem of different optical axes will have an effect on the consistency of the measurement results, which may result in the decrease of aiming and tracking performance for photoelectric devices. Therefore, in order to achieve the performance of accurately searching, observating and aiming at targets and improve the ability to the tracking and fighting targets, the research on testing technology of optical-axis consistency has a very importantly practical significance and promotion effect for photoelectric systems with multispectral and multi-optical axis.The paper summarizes optical-axis consistency testing technology and its development trend at home and abroad. On the basis of analyzing, research, and comparing some optical-axis consistency testing methods in the current, one method of field testing and calibration of optical-axis consistency among the laser, the visible-light, and the infrared optical axes is proposed. The testing method using 1.064 μm laser as a benchmark axis applies ZnS glass with full spectrum transmission and the broad spectrum light source with visible-light/infrared bands to directly forming visible-light/infrared targets, completing self-calibration of testing system. The telephoto-lens optical structure is used for avoiding the center-obstruction problem of reflective systems, improving the system transmission rate, and simplifying the volume of testing system, thereby much better suit to realize testing and calibration of optical-axis consistency of multi-optical-axis optoelectronic devices under field environment.Based on the field-testing and calibration method of optical-axis consistency of laser, visible light, and infrared light provided by the paper, the detailed design parameters of the testing system are determined after analyzing the working environment and technical indicators of the testing system. A telephoto-lens structure is adopted to complete the optical system design with a shared aperture and multiple spectra. The focal lengths of this optical system are consistently 680 mm throughout the visible-light, long-wave-infrared, and laser regions. In addition, the aperture of optical system is 230mm, whose maximum axial dimension is 510mm and maximum radial dimension is 393mm. Both aspheric and diffractive optical elements are used to correct the aberration of optical system and simplify the system structure. The design results show that the MTF of the long-wave infrared system reaches 0.4 when the spatial resolution is 17 lp/mm. When the spatial resolution is 107 lp/mm, the MTFs of the laser and visible-light system reach 0.3 and 0.5, respectively. These values approximate the diffraction limit of the optical system. By analyzing the tolerance and the measurement uncertainty of testing system, it will ensure that the optical system can be realized after alignment. At the same time, through field-testing, the consistency deviations of the testing device are found to be less than 10" for the infrared, visible-light, and laser optical axes, reaching the requirements of design. The whole testing system meets the development trend of automation and lightweight, possessing extensive application prospect for optical-axis consistency testing system.