Fan Peirong, Li Wenyi, Cui Xiaowei, Lu Mingquan
Department of Electronic Engineering, Tsinghua University, Beijing 100084, China.
Satellite Navigation Center, Haidian District, Beijing 100094, China.
Sensors (Basel). 2019 Aug 17;19(16):3586. doi: 10.3390/s19163586.
Robust and centimeter-level Real-time Kinematic (RTK)-based Global Navigation Satellite System (GNSS) positioning is of paramount importance for emerging GNSS applications, such as drones and automobile systems. However, the performance of conventional single-rover RTK degrades greatly in urban environments due to signal blockage and strong multipath. The increasing use of multiple-antenna/rover configurations for attitude determination in the above precise positioning applications, just as well, allows more information involved to improve RTK positioning performance in urban areas. This paper proposes a dual-antenna constraint RTK algorithm, which combines GNSS measurements of both antennas by making use of the geometric constraint between them. By doing this, the reception diversity between two antennas can be taken advantage of to improve the availability and geometric distribution of GNSS satellites, and what is more, the redundant measurements from a second antenna help to weaken the multipath effect on the first antenna. Particularly, an Ambiguity Dilution of Precision (ADOP)-based analysis is carried out to explore the intrinsic model strength for ambiguity resolution (AR) with different kinds of constraints. Based on the results, a Dual-Antenna with baseline VEctor Constraint algorithm (RTK) is developed. The primary advantages of the reported method include: 1) Improved availability and success rate of RTK, even if neither of the two single-antenna receivers can successfully solve the AR problem; and 2) reduced computational burden by adopting the concept of measurement projection. Simulated and real data experiments are performed to demonstrate robustness and precision of the algorithm in GNSS-challenged environments.
强大且基于厘米级实时动态（RTK）的全球导航卫星系统（GNSS）定位对于无人机和汽车系统等新兴GNSS应用至关重要。然而，由于信号阻塞和强烈的多径效应，传统单基站RTK在城市环境中的性能会大幅下降。在上述精确定位应用中，越来越多地使用多天线/多基站配置进行姿态确定，同样也能让更多信息参与进来，以提高城市地区的RTK定位性能。本文提出了一种双天线约束RTK算法，该算法利用两天线之间的几何约束来合并两天线的GNSS测量值。通过这样做，可以利用两天线之间的接收分集来提高GNSS卫星的可用性和几何分布，而且，第二天线的冗余测量有助于减弱对第一天线的多径效应。特别是，进行了基于精度因子模糊度稀释（ADOP）的分析，以探索不同类型约束下用于模糊度解算（AR）的内在模型强度。基于这些结果，开发了一种带基线矢量约束的双天线算法（RTK）。所报道方法的主要优点包括：1）即使两个单天线接收机都无法成功解决AR问题，也能提高RTK的可用性和成功率；2）通过采用测量投影的概念减轻计算负担。进行了模拟和实际数据实验，以证明该算法在GNSS受限环境中的鲁棒性和精度。
