Stochastic modeling of BDS2/3 observations with application to RTD/RTK positioning
Stochastic modeling of BDS2/3 observations with application to RTD/RTK positioning
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BDS2/3 观测的随机建模及其应用于 RTD/RTK 定位
DOI：
10.1088/1361-6501/ab1fad
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发表时间：
2019
影响因子：
2.4
通讯作者：
Zha Jiuping
中科院分区：
文献类型：
--
作者：
Hou Pengyu;Zhang Baocheng;Yuan Yunbin;Zhang Xiao;Zha Jiuping
中国北斗导航卫星系统（BDS）正逐步从区域系统（BDS 2）过渡到全球系统（BDS 3），为全球用户提供定位、导航和授时（PNT）服务。实时差分（RTD）和实时动态（RTK）定位在北斗系统的应用中起着重要的作用，而这两种技术的最佳性能依赖于随机模型的正确选择。本文采用最小二乘方差分量估计（LS-VCE）方法，建立了零基线和短基线条件下，考虑高程精度、互相关和时间相关的BDS 2/3观测值的实际随机模型。影响随机模型的因素，包括接收机多径抑制技术和天线类型，进行了研究。结果表明，在零基线收集的所有观测值中，BDS 3 B1 C和B2 a观测值具有相对较高的精度，这可能归因于先进的信号结构和调制技术，而在短基线中，由于多径效应的存在，这种上级性能不存在。在BDS 3 B1 I和B3 I相位观测之间发现了大约0.8的正相关性，并且在BDS 2相位观测之间存在类似的相关性。当应用多径抑制技术时，时间相关性被削弱，并且观测的随机特性是特定于天线类型的。利用所建立的随机模型，仅BDS 3的RTD/RTK定位精度与仅BDS 2的定位精度相当，而BDS 2 + BDS 3的RTD/RTK定位精度相对于仅BDS 2的情况提高了40%~ 65%。
The Chinese BeiDou navigation satellite system (BDS) is gradually transitioning from a regional system (BDS2) to a global system (BDS3) to provide its positioning, navigation and timing (PNT) services to users worldwide. Real-time differencing (RTD) and real-time kinematic (RTK) positioning play important roles in the applications of BDS, and the optimal performance of these two techniques relies upon the proper choice of stochastic model. In this paper, the least-squares variance component estimation (LS-VCE) method is adopted to establish a realistic stochastic model considering the elevation-dependent precision, cross-correlation and time correlation for BDS2/3 observations collected in zero and short baselines. The factors affecting the stochastic model, including the receiver multipath mitigation technique and antenna type, are investigated. The results show that BDS3 B1C and B2a observations possess relatively high precision among all observations collected in the zero baseline, which may be attributed to the advanced signal structure and modulation technique, whereas this superior performance is absent in the short baseline due to the presence of multipath effects. A positive correlation of approximately 0.8 is found between BDS3 B1I and B3I phase observations, and similar correlations exist between BDS2 phase observations. The time correlations are weakened when applying the multipath mitigation technique, and the stochastic characteristics of observations are specific to the type of antenna. The BDS3-only RTD/RTK positioning precision with our established stochastic model is comparable to the BDS2-only positioning precision, and the BDS2 + BDS3 RTD/RTK positioning precision is improved by 40% to 65% with respect to the BDS2-only case.