森林环境下的北斗卫星导航系统性能分析

Performance of Beidou navigation satellite system in forested conditions

为了解乔木林应用场景中的定位性能,指导林业行业科学应用GNSS技术,该文探究了多种立地条件下中高郁闭度林分中BDS与GPS的应用能力,采集了森林环境中单BDS和单GPS这两种定位模式下一定时长的GNSS信号,并定量计算了平面和垂直方向的定位误差,以及GNSS几何精度因子和信噪比等参数。通过3个时长水平定位精度、垂直定位精度、卫星数量、DOP值、信噪比等观测参数的误差平均值、极值、方差等的对比分析表明,目前基于单频伪距定位的原理,我国北斗卫星导航系统的定位性能指标与GPS基本一致。选用专业设备且单点求平均是满足林下高可靠性(优于5 m)定位要求的重要手段与方法,瞬时数据只适合森林环境中低可靠性(10 m)的导航作业要求,如果要满足亚米级及更高精度的定位需求,现阶段需采用差分技术。

In order to understand the performance of GNSS in forested conditions and guide the scientific application of the technology in forestry field,this paper explored the difference of positioning accuracy of BDS and GPS in middle and high canopy density stands under various site conditions.The GNSS signals of the handheld terminal in closed canopy stand under various site conditions were collected.The positioning errors in horizontal and vertical directions and other parameters were analyzed quantitatively.The differences of Geometric Dilution of Precision,signal-to-noise ratio and errors in three periods were compared.At present,the performance of BDS was close to GPS.It was considered that the selection of professional receiver and single point average were an important means and methods to meet the conventional needs of positioning better than5 min the forestry.Instantaneous data was only suitable for low reliability(10 m)navigation in forest environment.Only using differential technology could meet the requirements of sub-meter high precision operation.