2018 ASR: Performance analysis of PPP ambiguity resolution with UPD products estimated from different scales of reference station networksYang Ling, Li Bofeng, Li Haojun, Chris Rizos, Shen YunzhongInteger ambiguity fixing with uncalibrated phase delay (UPD) products can significantly shorten the initialization time and improve the accuracy of precise point positioning (PPP). Since the...
201 测绘学报: 时间相关观测的几种动态数据处理方法李博峰, 章浙涛现代大地测量数据中往往存在时间相关性,忽略观测值时间相关性会影响参数估值的精度和可靠性。因此,本文研究了几种时间相关观测的动态数据处理方法。首先,对观测值时间相关性的处理方法进行了扩展和统一。利用极大验后估计原理,提出了第3种思路,并在无历元公用参数和有历元公用参数两类模型下,详细推导了去相关变换法、差分变换法和极大验后估计法这3...
2018 同济大学学报: 全球参考站网窄巷非校准相位延迟产品时变特性王思遥, 李博峰窄巷非校准相位延迟(UPD)产品的质量和可用性是影响精密单点定位模糊度固定(PPP-AR)效率的重要因素.采用全球108个国际GPS服务(International GPS Service,IGS)测站观测数据,计算了基于全球参考站网的窄巷UPD产品,分析了窄巷UPD产品的变化特性,其单日变化量最大可达0.6周.通过分析UPD改正后的模糊度残差,论证了UPD产品和用户端模糊度均受...
2017 测绘学报: 3种GPS+BDS组合PPP模型比较与分析臧楠, 李博峰, 沈云中无电离层组合和非组合模型是GNSS精密单点定位(PPP)常用的两种函数模型。本文通过详细分析PPP的两种函数模型各类参数间的相关特性,建立了参数独立的函数模型。对非组合PPP模型的电离层参数引入虚拟观测方程进行约束,有效提高了PPP的收敛速度。最后,从定位精度和收敛时间两方面分析不同函数模型的GPS单系统和GPS+BDS组合PPP静态、模拟动态定位效果...
2017 导航定位学报: 顾及自变量与因变量误差及相关性的线性回归 BDS超宽巷实时定位分析李振，李博峰为了提高BDS超宽巷实时定位的精度,充分利用超宽巷模糊度单历元固定的优势,研究直接采用超宽巷进行RTK定位:提出忽略电离层和消电离层2种超宽巷RTK定位模型,并分析比较2种模型的定位效果。结果表明:在50km范围内,忽略电离层模型的平面定位精度可达到15cm以内,消电离层模型的平面定位精度可达到0.5m以内;在中长距离的情...
2017 ASR: The influence of improper stochastic modeling of BeiDou pseudoranges on system reliabilityYang Ling, Li Bofeng, Li Haojun, Chris Rizos, Shen YunzhongStochastic models are important in Global Navigation Satellite System (GNSS) estimation problems, not only for parameter estimation, or precision assessment, but also for deriving system reliability and integrity measures. China...
2017 J Geod: Improving BeiDou precise orbit determination using observations of onboard MEO satellite receiversGe Haibo, Li Bofeng, Ge Maorong, Shen YunzhongIn recent years, the precise orbit determination (POD) of the regional Chinese BeiDou Navigation Satellite System (BDS) has been a hot spot because of its special constellation consisting of five geostationary earth orbit (GEO) sa...
2017 JSE: Extension of internal reliability analysis regarding separability analysisLi Bofeng, Li Zheng, Zhang Zhiteng, Tan Yu'anMinimal detectable bias (MDB) describes a system's general ability to detect the existence of a single outlier. However, successful identification probability is closely related to the correlations between w-statistics. When the correlation is high, the vali...
2017 J Geod: Extra-wide-lane RTK of triple-frequency GNSS signalsLi Bofeng, Li Zheng, Zhang Zhiteng, Tan Yu'anTriple-frequency signals have thus far been available for all satellites of BeiDou and Galileo systems and for some GPS satellites. The main benefit of triple-frequency signals is their formation of extra-wide-lane (EWL) combinations whose ambiguities can be instantaneously fi...
2017 GPS Solut: Impacts of BeiDou stochastic model on reliability: overall test, w-test and minimal detectable biasLi Bofeng, Zhang Lei, Verhagen SandraExtensive studies have concluded that the GNSS observations are heteroscedastic and physically correlated. Typically, the observation precisions are elevation dependent and between-frequency cross-correlations and time correlations exi...
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