2018 RS: Initial assessment of precise point positioning with LEO enhanced Global Navigation Satellite Systems (LeGNSS)Gw Haibo, Li Bofeng, Ge Maorong, Zang Nan, Nie Liangwei, Shen Yunzhong, SchThe main challenge of precise point positioning (PPP) applications is the long convergence time of typically a half hour, or even more, to achieve centimeter accuracy. Even when the multi-const...
2018 ApplSci: GNSS-based verticality monitoring of super-tall buildingsZhang Xing, Zhang Yongyi, Li Bofeng, Qiu GuangxinIn general, a laser plummet is used to transmit coordinates of reference points from the ground layer-by-layer, which can effectively control the verticality of super-tall buildings. However, the errors in transmission will accumulate with increasing height and motio...
2018 ASR: Modeling of the GPS satellite clock error and its performance evaluation in precise point positioningLi Haojun, Liao Xilin, Li Bofeng, Yang LingThe different functions, which include the polynomial and the harmonics based functions, are used to model and extrapolate the GPS satellite clock for simplifying the service mode and real-time application. The modeling accuracy decr...
2018 JSE: Efficient approximation to a fully populated variance-covariance matrix for RTK positioningZhang Zhetao, Li Bofeng, Shen YunzhoGlobal navigation satellite system (GNSS) observations have been shown to be physically correlated. Disregarding the physical correlations in a variance-covariance matrix (VCM) will lead to adverse impacts on GNSS applications. Typically, physical co...
2018 J Geod: A procedure for the significance testing of unmodeled errors in GNSS observationsLi Bofeng, Zhang Zhetao, Shen Yunzho, Yang LingIt is a crucial task to establish a precise mathematical model for global navigation satellite system (GNSS) observations in precise positioning. Due to the spatiotemporal complexity of, and limited knowledge on, systematic errors in GNSS observa...
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...
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