Robust direct georeferencing of lightweight UAV

该分项目的目标是制定方法，以高精度（<1厘米，<1°）和高鲁棒性实时确定轻型航空器（<5公斤）的位置和方向，以便提供直接的地理参考信息。高鲁棒性对于车辆的自主导航是必要的。地图的地理参考需要高精度，该地图已从平台上的不同测绘传感器重建。因此，不需要地面控制点。精确的位置和方向信息还为基于图像的3D重建算法提供了高质量的近似解。实时能力对于自主操作是必要的，并且还允许地图的快速近实时地理参考，以便使飞行计划适应当前情况。所面临的挑战是由于车辆的尺寸和重量限制以及算法的开发而导致的多传感器系统的技术实现，该算法基于各种传感器模态来确定位置和方向。在项目的第一阶段之后，可以根据预期的规范在理想条件下估计位置和方向。该估计基于GNSS载波相位观测、惯性传感器数据和三轴罗盘模块。计算是在飞行过程中进行的，以便为自主导航过程和三维重建算法提供真实的时间信息，该提案第二阶段的主要目标是通过增加Glonass系统的观测以及对全球导航卫星系统观测条件的位置和环境依赖性预测来增强基于全球导航卫星系统的位置确定。另一个目标是在没有任何或只有少数几个可用的全球导航卫星系统观测的情况下增强位置确定。这是通过以某种方式扩展估计算法来完成的，任何额外的传感器信息，例如来自相机或激光扫描仪的信息，都可以用于桥接这些情况。另一个目标是评估飞行过程中的地理定位精度。

The goal of this subproject is the development of methods, which allow the real-time determination of the position and the orientation of a lightweight aerial vehicle (<5kg) with high accuracy (<1cm, <1°) and high robustness in order to provide direct georeferencing information. A high robustness is necessary for the autonomous navigation of the vehicle. A high accuracy is needed for the georeferencing of the maps, which has been reconstructed from the different mapping sensors on the platform. Therefore no ground control points are needed. The accurate position and orientation information also provide a high quality approximate solution for the image based 3D reconstruction algorithms. The real-time capability is necessary for the autonomous operation and also allows a fast near real-time georeferencing of the maps, in order to adapt the flight plan to the current situation. The challenges are the technical realization of the multi-sensor system due to the size and weight constraints of the vehicle and the development of the algorithms, which determine the position and orientation based on various sensors modalities. After the first phase of the project it is possible to estimate the position and orientation under ideal conditions in accordance with the intended specification. This estimation is based on GNSS carrier phase observations, inertial sensor data and a three axis compass module. The calculation is performed during the flight in order to provide real time information to the process of autonomous navigation and to the 3D reconstruction algorithms.The main goals of the second phase of the proposal are the robustification of the GNSS based position determination by adding observation from the Glonass system as well as the location and environment dependant prediction of the GNSS observation conditions. Another goal is the robustification of the position determination in situations without any or with only a few available GNSS observations. This is done by extending the estimation algorithms in a way, that any additional sensor information, e.g. coming from the cameras or the laserscanner, can be used to bridge these situations. Another goal is the evaluation of the georeferencing accuracy during the flight.