城市峡谷中基于GDOP和NHC的GPS/IMU组合导航方法

GPS/IMU Integrated Navigation Technique Based on GDOP and NHC in Urban Canyon

针对在林荫道、高架桥和隧道等城市峡谷中全球定位系统(GPS)信号易发生遮挡、干扰,导致导航定位精度低、连续性和可靠性差的问题,提出了一种基于几何精度因子(GDOP)和非完整性约束(NHC)的GPS/惯性测量单元(IMU)组合导航方法。其中,通过利用GDOP实现卫星定位构型优劣和定位精度的衡量,从而构建基于GDOP值的GPS/IMU组合导航量测更新模型。同时,为了进一步提高组合导航系统的精度,将NHC应用于该组合导航系统中。实验结果表明,所提方法水平和三维定位均方根误差分别是3.88 m和4.78 m,相比于传统GPS/IMU组合导航方法的9.25 m和13.53 m分别提高了58.06%和64.67%,可以有效抑制GPS信号受环境干扰影响组合导航定位精度和可靠性的问题。

GPS signals are easily blocked and disturbed in urban canyons, resulting in the degraded accuracy, continuity and reliability of the navigation performance. In order to deal with the issue a GPS/IMU integrated navigation algorithm based on the geometric dilution precision(GDOP) and non-holonomic constraints(NHC) is proposed. As GDOP is able to evaluate the geometry of the constellation and positioning accuracy, a measurement update strategy of the GPS/IMU integration using GDOP is proposed.In addition, the NHC based constraint is applied in the integration. The experimental results show that for the proposed method, the root mean square errors of horizontal and 3D positioning results are 3.88 m and 4.78 m respectively, which are 58.06% and 64.67%higher than the 9.25 m and 13.53 m of the traditional GPS/IMU integrated navigation method respectively. The proposed method can effectively improve the positioning accuracy and reliability of integrated navigation system in the urban areas.