Investigation On The Characteristics Of Planar Array Three-Dimensional Airborne Laser Radar Motion Imaging

Airborne laser radar three-dimensional measurement technology provides a new means for obtaining high-resolution geo-spatial information. It can quickly get high-precision, high spatial resolution digital elevation models, which is the vertical structure of ground targets. It has a broad development prospects and application requirements in the data collection of 3d geospatial information.This paper first introduces the technology development situation of airborne laser radar and other airborne range finding measurement, in which the imaging laser radar based on the distance measurement principle of gain modulation is with a very good development prospects. This laser radar uses image intensifier to modulate the gain of laser echo, and eventually get CCD intensity images which will be used to calculate the 3d information of the target. Then discussed the structure of this imaging laser radar for airborne survey, and its ranging performance under shot-noise limited. In order to improve the ranging accuracy, two methods are proposed which are increasing the integration time with multi-pulse exposure and overlaying multi-frame by range image registration. The first method is to receive many echo pulses in integration time, and motion compensation is needed to prevent image blurring; the second method to improve the ranging accuracy by overlaying images to increase the signal strength is in cognizance of the existence of large superposition area between range image sequences.When laser radar taking long integration time, the existence of airborne platform's random motion and non-ideal motion compensation will cause pixel crosstalk. Then an analysis of this crosstalk effects on the radar intensity image and range image is demonstrated.The survey process of airborne imaging laser radar is simulated by programming. Program takes into account various factors on the simulation results, including the establishment of a virtual 3d scene on the ground, random motion of flying platform, the motion compensation during exposure time, non-uniform light intensity distribution from light source, detector noise model and signal quantification, and so on. These factors are compiled into modular program. Through user interface to set simulation parameter and get results. In the end, an analysis of multi-pulse exposure and crosstalk effects on the radar image quality is presented with the simulation results. Finally, there is an analysis of the whole system, and the entire project is summarized and prospects.