伪卫星辅助北斗定位精度改进方法

由于北斗二号一期系统卫星集中分布在赤道附近,导致国土范围内接收机南北方向定位精度偏低,且由于可视卫星均为正仰角,导致接收机垂直方向定位精度也偏低的问题,提出了利用地面伪卫星改善用户观测几何结构的方法来提高一定区域范围内北斗接收机的定位精度。推导了伪卫星与真实卫星组合的最小二乘定位算法模型,并给出了用于定位精度评估的南北和垂直方向的精度衰减因子值。仿真结果表明:在用户使用范围的北部地区布设伪卫星可有效降低用户南北方向以及垂直方向的精度衰减因子值,从而有效改善定位精度。

BeiDou positioning accuracy improvement based on pseudolites

BeiDou satellites concentrates near the equator, which results in a low positioning accuracy within the homeland in north-south direction. Because the visible satellites are positive elevation, the vertical positioning accuracy is also low. To solve the above problems, a method to improve BeiDou satellites positioning accuracy was proposed, which uses pseudolites to improve the user observation geometry. The least square positioning algorithm based on the combination of pseudolites and satellites was derived. Dilution of positioning in north-south and vertical direction were also proposed to evaluate the positioning precision. Simulation results show that the dilution of positioning in north-south and vertical direction can be reduced effectively by lying pseudolites in the north area of users, thus the positioning accuracy can be effectively improved.