基于DDF2的RTS平滑方法在机载分布式POS中的应用

A RTS Smoother Based on Second-order Divided Difference Filter Applied to Airborne Distributed POS

机载分布式POS是一种基于惯性/卫星组合技术的柔性基线、多节点、高精度时空测量系统,是多任务航空遥感载荷高精度成像的关键装置。为了解决机载分布式POS因柔性基线效应导致的大失准角非线性问题,提出了将基于二阶插值微分滤波(Second-order Divided Difference Fil-ter,DDF2)的(RTS Rauch Tung Striebel,RTS)平滑方法应用于机载分布式POS。首先,针对机载分布式POS的大失准角非线性问题,建立了非线性系统状态模型和量测模型。其次,基于DDF2提出了分布式POS传递对准RTS平滑估计方法,以获取更高精度的运动参数。最后,通过半物理车载实验验证了相比传统方法,此方法的航向测量误差由0.0060°降至0.0041°,精度提高了31.67%。

The distributed POS is a highly precision measurement system based on SINS/GPS integrated navigation technology. It is a key to highly-accurate imaging device for multi-task airborne loading remote sensors. The distributed position and orientation system (POS) uses transfer alignment to accurately measure multi-node time-spatial reference information. In order to solve the problem of nonlinear error, the rauch tung striebel (RTS) based on second-order divided difference filter (DDF2) for offline transfer alignment of airborne POS is proposed. Firstly, a nonlinear state and measurement model are established based on large misalignment. Then, a nonlinear RTS based on DDF2 is proposed to obtain higher-precision motion parameters for airborne POS. Finally, the experiment is carried out. The results show that the accuracy of heading is improved by 31.67%.