Data simulation of LADAR sensor: Focusing on geometric modeling

LADAR (LAser Detection And Ranging or Laser Radar) can rapidly generate 3D points by sampling the surfaces of targets using laser pulses, which can be efficiently utilized to reconstruct 3D models of the targets automatically. To make wide use of LADAR, it is necessary to assess the data quality and to develop data processing algorithms. However, the accuracy verification of LADAR system is difficult, because we cannot know the accurate reflected positions of the returned signals at target's surface. Under the consideration of this difficulty, the verification based on LADAR simulation can be a more feasible alternative solution. The purpose of this study is to derive the geometric models of such LADAR sensors and to generate simulated data based on these models. Here, we derived the sensor equation by modeling not only the geometric relationships between the LADAR sub-modules, such as GPS, INS, Laser Scanner but also the systematic errors associated with them. This is an important step to establish mutual geometric and time correspondence among the individual sensors on a multi-sensor system. The geometric correspondence means that each sensor is defined with its position and attitude in a common coordinate system. And the time correspondence means that individual sensor time is synchronized. Based on this equation (the geometric model), we developed a program that generates simulated data with the system parameters of a LADAR sensor, a terrain model, and its trajectories over this model given. The results of this study will be useful for the system design of a LADAR sensor and the algorithmic development for LADAR applications.