scholarly journals Accurate Evaluation of Vertical Tidal Displacement Determined by GPS Kinematic Precise Point Positioning: A Case Study of Hong Kong

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2559 ◽  
Author(s):  
Guoguang Wei ◽  
Qijie Wang ◽  
Wei Peng
Keyword(s):  
Hong Kong ◽  
Precise Point Positioning ◽  
The Body ◽  
Ocean Tide ◽  
Depth Analysis ◽  
Global Positioning ◽  
Point Positioning ◽  
Tidal Constituents ◽  
Tide Effect

Global Positioning System (GPS) kinematic precise point positioning (KPPP) is an effective approach for estimating the Earth’s tidal deformation. The accuracy of KPPP is usually evaluated by comparing results with tidal models. However, because of the uncertainties of the tidal models, the accuracy of KPPP-estimated tidal displacement is difficult to accurately determine. In this paper, systematic vector differences between GPS estimates and tidal models were estimated by least squares methods in complex domain to analyze the uncertainties of tidal models and determine the accuracy of KPPP-estimated tidal displacements. Through the use of GPS data for 12 GPS reference stations in Hong Kong from 2008 to 2017, vertical ocean tide loading displacements (after removing the body tide effect) for eight semidiurnal and diurnal tidal constituents were obtained by GPS KPPP. By an in-depth analysis of the systematic and residual differences between the GPS estimates and nine tidal models, we demonstrate that the uncertainty of the tidal displacement determined by GPS KPPP for the M2, N2, O1, and Q1 tidal constituents is 0.2 mm, and for the S2 constituent it is 0.5 mm, while the accuracy of the GPS-estimated K1, P1, and K2 tidal constituents is weak because these three tidal constituents are affected by significant common-mode errors. These results suggest that GPS KPPP can be used to precisely constrain the Earth’s vertical tidal displacement in the M2, N2, O1, and Q1 tidal frequencies.

scholarly journals Seasonal Variation of GPS-Derived the Principal Ocean Tidal Constituents’ Loading Displacement Parameters Based on Moving Harmonic Analysis in Hong Kong

2021 ◽  
Vol 13 (2) ◽  
pp. 279 ◽  
Author(s):  
Maosheng Zhou ◽  
Xin Liu ◽  
Jiajia Yuan ◽  
Xin Jin ◽  
Yupeng Niu ◽  
...  
Keyword(s):  
Hong Kong ◽  
Seasonal Variation ◽  
Harmonic Analysis ◽  
Seasonal Variations ◽  
Ocean Tide ◽  
Atmospheric Loading ◽  
Global Positioning ◽  
Ocean Loading ◽  
Tidal Constituents ◽  
Annual Signal

The classical harmonic analysis (CHA) method only can be used to obtain the harmonic constants (amplitude and phase) of ocean tide loading displacement (OTLD). In fact, there are significant seasonal variations in the harmonic constants of OTLD. A moving harmonic analysis (MHA) method is proposed, which can effectively capture the seasonal variation of OTLD parameters. Based on 5 years of kinematic coordinate time series in direction U of six Global Positioning System (GPS) stations in Hong Kong, the MHA method is used to explore the seasonal variation of the OTLD parameters of the 6 principal tidal constituents (M2, S2, N2, K1, O1, Q1). The influence of mass loading on the seasonal variation of OTLD parameters is analyzed. The results show that there are obviously seasonal variations in OTLD parameters of the 6 principal tidal constituents in Hong Kong. The OTLD’s amplitude’s changes of the 6 principal tidal constituents are around 4–25.1% and the oscillation ranges of OTLD’s phase parameters vary from 8.8° to 20.4°. Among the seasonal variations of OTLD parameters, the annual signal, the semi-annual signal, and the ter-annual signal are the most significant. By analyzing the influence of atmospheric loading on the seasonal variation of OTLD parameters, it is found that atmospheric loading has certain contribution to the seasonal variation of OTLD parameters. Hydrological loading and non-tidal ocean loading have little influence on the seasonal variation of OTLD parameters.

scholarly journals Simulation case study of deformations and landslides using real-time GNSS precise point positioning technique

2016 ◽  
Vol 7 (6) ◽  
pp. 1856-1873 ◽  
Author(s):  
Raquel M. Capilla ◽  
José Luis Berné ◽  
Angel Martín ◽  
Raul Rodrigo
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Positioning Technique ◽  
Point Positioning

scholarly journals The Impact of Different Ocean Tide Loading Models on GNSS Estimated Zenith Tropospheric Delay Using Precise Point Positioning Technique

2020 ◽  
Vol 12 (18) ◽  
pp. 3080
Author(s):  
Jinglei Zhang ◽  
Xiaoming Wang ◽  
Zishen Li ◽  
Shuhui Li ◽  
Cong Qiu ◽  
...  
Keyword(s):  
Precise Point Positioning ◽  
Precipitable Water ◽  
Global Navigation Satellite Systems ◽  
Ocean Tide ◽  
Tropospheric Delay ◽  
Ocean Tide Loading ◽  
Zenith Tropospheric Delay ◽  
Point Positioning ◽  
The Difference ◽  
The Impact

Global navigation satellite systems (GNSSs) have become an important tool to derive atmospheric products, such as the total zenith tropospheric delay (ZTD) and precipitable water vapor (PWV) for weather and climate studies. The ocean tide loading (OTL) effect is one of the primary errors that affects the accuracy of GNSS-derived ZTD/PWV, which means the study and choice of the OTL model is an important issue for high-accuracy ZTD estimation. In this study, GNSS data from 1 January 2019 to 31 January 2019 are processed using precise point positioning (PPP) at globally distributed stations. The performance of seven widely used global OTL models is assessed and their impact on the GNSS-derived ZTD is investigated by comparing them against the ZTD calculated from co-located radiosonde observations. The results indicate that the inclusion or exclusion of the OTL effect will lead to a difference in ZTD of up to 3–15 mm for island stations, and up to 1–2 mm for inland stations. The difference of the ZTD determined with different OTL models is quite small, with a root-mean-square (RMS) value below 1.5 mm at most stations. The comparison between the GNSS-derived ZTD and the radiosonde-derived ZTD indicates that the adoption of OTL models can improve the accuracy of GNSS-derived ZTD. The results also indicate that the adoption of a smaller cutoff elevation, e.g., 3° or 7°, can significantly reduce the difference between the ZTDs determined by GNSS and radiosonde, when compared against a 15° cutoff elevation. Compared to the radiosonde-derived ZTD, the RMS error of GNSS-derived ZTD is approximately 25–35 mm at a cutoff elevation of 15°, and 15–25 mm when the cutoff elevation is set to 3°.

Subsidence is determined in the heart of the Central Valley using Post Processed Static and Precise Point Positioning techniques

2020 ◽  
Vol 14 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Y. Facio ◽  
M. Berber
Keyword(s):  
Data Processing ◽  
Global Positioning System ◽  
Precise Point Positioning ◽  
Central Valley ◽  
Gps Data ◽  
Positioning System ◽  
Online Services ◽  
Global Positioning ◽  
System Data ◽  
Point Positioning

AbstractPost Processed Static (PPS) and Precise Point Positioning (PPP) techniques are not new; however, they have been refined over the decades. As such, today these techniques are offered online via GPS (Global Positioning System) data processing services. In this study, one Post Processed Static (OPUS) and one Precise Point Positioning (CSRS-PPP) technique is used to process 24 h GPS data for a CORS (Continuously Operating Reference Stations) station (P565) duration of year 2016. By analyzing the results sent by these two online services, subsidence is determined for the location of CORS station, P565, as 3–4 cm for the entire year of 2016. In addition, precision of these two techniques is determined as ∼2 cm. Accuracy of PPS and PPP results is 0.46 cm and 1.21 cm, respectively. Additionally, these two techniques are compared and variations between them is determined as 2.5 cm.

Lucilla You Min and Her Embodiment of a Cosmopolitan Fantasy

2019 ◽  
Vol 5 (1) ◽  
pp. 113-140
Author(s):  
Erica Ka-yan Poon
Keyword(s):  
Hong Kong ◽  
The Body ◽  
Border Crossing ◽  
Leadership Role ◽  
Hong Kong Cinema ◽  
Star Studies ◽  
Cultural Competition ◽  
A Site ◽  
The Cold War

Lucilla You Min, who acted in Japanese and Hong Kong coproduced films in the early 1960s, is a valuable case study for postwar East Asian border-crossing star studies. This article conceptualizes the body of the star as a site of constructed meaning, and argues that You Min's embodiment of cosmopolitan fantasy as constructed by the studios she worked for was fraught with corporate and cultural competition in the Cold War era. The first part examines how Japanese cinema's discourses of publicity constructed You Min's embodiment of the imaginary of tōyō—an expression of Japan's desire for a leadership role in mediating between Asia and the West. The second part analyzes how Hong Kong cinema constructed the imaginary of the cosmopolitan, embodied by You Min's seemingly natural adaptability in world travel.

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