Geometry‐specified troposphere decorrelation for subcentimeter real‐time kinematic solutions over long baselines

Abstract

[1] Real-time kinematic (RTK) GPS techniques have been extensively developed for applications including surveying, structural monitoring, and machine automation. Limitations of the existing RTK techniques that hinder their applications for geodynamics purposes are twofold: (1) the achievable RTK accuracy is on the level of a few centimeters and the uncertainty of vertical component is 1.5-2 times worse than those of horizontal components and (2) the RTK position uncertainty grows in proportional to the base-torover distances. The key limiting factor behind the problems is the significant effect of residual tropospheric errors on the positioning solutions, especially on the highly correlated height component. This paper develops the geometry-specified troposphere decorrelation strategy to achieve the subcentimeter kinematic positioning accuracy in all three components. The key is to set up a relative zenith tropospheric delay (RZTD) parameter to absorb the residual tropospheric effects and to solve the established model as an ill-posed problem using the regularization method. In order to compute a reasonable regularization parameter to obtain an optimal regularized solution, the covariance matrix of positional parameters estimated without the RZTD parameter, which is characterized by observation geometry, is used to replace the quadratic matrix of their "true" values. As a result, the regularization parameter is adaptively computed with variation of observation geometry. The experiment results show that new method can efficiently alleviate the model's ill condition and stabilize the solution from a single data epoch. Compared to the results from the conventional least squares method, the new method can improve the longrange RTK solution precision from several centimeters to the subcentimeter in all components. More significantly, the precision of the height component is even higher. Several geosciences applications that require subcentimeter real-time solutions can largely benefit from the proposed approach, such as monitoring of earthquakes and large dams in real-time, high-precision GPS leveling and refinement of the vertical datum. In addition, the high-resolution RZTD solutions can contribute to effective recovery of tropospheric slant path delays in order to establish a 4-D troposphere tomography.Citation: Li, B., Y. Feng, Y. Shen, and C. Wang (2010), Geometry-specified troposphere decorrelation for subcentimeter realtime kinematic solutions over long baselines,

Inter-System Differencing between GPS and BDS for Medium-Baseline RTK Positioning

“…The DD tropospheric delay can be corrected with an empirical troposphere model, e.g., the GPT2w model [20]. If the baseline is longer than 30 km or has a large height difference between two stations, a relative zenith troposphere delay (RZTD) parameter can be estimated as a random-walk process to absorb the residual tropospheric biases [21]. For the ionospheric delay in dual-frequency data, there are usually two processing models.…”

A modified un-combined model to improve the performance of precise point positioning: model and test results

“…The biases are about 0.5, 0.1, 0.6, 3.7 and 10.0 cm in the north, east, up, 2D and 3D, respectively, which are better than that of the UD model. In addition, the standard deviations for the four models are about 2.4-4.5 cm in both the north and east components, and 10.5-13.9 cm in the up component resulted from the strong correlation between the up component and the tropospheric delay (Li et al 2010). As can be seen from Fig.…”

CenterPoint RTX Teknolojisinin Doğruluk ve Tekrarlana bilirliğinin Araştırılması

“…Günümüzde klasik gerçek zamanlı kinematik (RTK) veya ağ-RTK teknikleri birkaç saniyelik yakınsama süresinde kullanıcılara cm seviyesinde, üç boyutlu ve gerçek zamanlı çözüm sunabilmeleri sebebiyle yoğun şekilde kullanılmaktadırlar. Klasik RTK tekniği referans ve gezen alıcı olmak üzere en az iki GNSS alıcısı kullanımı gerektirmektedir (Li, Feng, Shen, & Wang, 2010). Ayrıca, uydu yörünge hataları ve atmosferik hatalar sebebiyle bu iki alıcı arasındaki mesafe yaklaşık 20 km ile sınırlı kalmaktadır (Lambrou & Kanellopoulos, 2018;Li et al, 2010).…”

“…Klasik RTK tekniği referans ve gezen alıcı olmak üzere en az iki GNSS alıcısı kullanımı gerektirmektedir (Li, Feng, Shen, & Wang, 2010). Ayrıca, uydu yörünge hataları ve atmosferik hatalar sebebiyle bu iki alıcı arasındaki mesafe yaklaşık 20 km ile sınırlı kalmaktadır (Lambrou & Kanellopoulos, 2018;Li et al, 2010). Veri iletiminde radyo bağlantısı veya internet erişimine ihtiyaç duyması da bu yöntemin diğer önemli dezavantajlarındandır.…”