Global Navigation Satellite System–Acoustic ranging (GNSS-A) technology can achieve centimeter-level seafloor positioning. However, the horizontal gradient of ocean sound speed limits positioning accuracy GNSS-A. This paper evaluates impact gradients on GNSS-A utilizing Bayesian estimation. Publicly available datasets from 2012 to 2021 were processed using strategies with and without estimating gradients. The comparison results demonstrates that has a significant but smaller vertical mean...

Abstract. The Global Navigation Satellite System (GNSS) offers precise, continuous monitoring of atmospheric water vapor, essential for weather forecasting and climate research. This study presents a high-accuracy precipitable vapor (PWV) dataset from 55 GNSS stations along China’s coast (2009–2019). PWV retrievals utilized weighted mean temperature (Tm) zenith hydrostatic delay (ZHD) derived fifth-generation European ReAnalysis (ERA5) products. After rigorous quality control, the achieved...

The Sansha Yongle Blue Hole (SYBH) is the deepest blue hole found anywhere to date. Study of SYBH can provide insight into interactions between wall morphology and many geological/hydrological mechanisms. A comprehensive investigation was carried out for first time in 2017 using a professional-grade underwater remotely operated vehicle (ROV) obtain accurate depth three-dimensional (3D) topographic data. resembles ballet dancer's shoe has volume ~499609 m3. observed portion at 301.19 m below...

Global Navigation Satellite System—Acoustic (GNSS-A) positioning is the main technique for seafloor geodetic positioning. A transceiver lever arm offset and sound velocity bias in seawater are systematic errors of GNSS-A technique. Based on data from a sea trial shallow water, this paper studies functional model The impact two analysed corresponding processing methods proposed. results show that measurement should be parameterised observation equation. Given high correlation between vertical...

Abstract This study quantifies the absolute sea level (ASL) change along coast of China from 1993 to 2019 using tide gauge (TG) and Global Navigation Satellite System (GNSS) data. The at 12 collocated TG GNSS stations Chinese are first analyzed by + Then ASL rise its spatial variation that in surrounding oceans studied data satellite altimetry products. results show relative varied 2.61 ± 0.76 5.56 0.70 mm/yr, while effect vertical land motion (VLM) ranged −1.46 0.30 1.07 0.38 mm/yr. After...

A motile, Gram-stain-negative, non-pigmented bacterial strain, designated MGL06T, was isolated from seawater of the South China Sea on selection medium containing 0.1 % (w/v) malachite green. Strain MGL06T showed highest 16S rRNA gene sequence similarity to Rhizobium vignae CCBAU 05176T (97.2 %), and shared 93.2-96.9 with type strains other recognized species. Phylogenetic analyses based housekeeping sequences that strain belonged genus Rhizobium. Mean levels DNA-DNA relatedness between R....

In this study, a numerical method was developed based on peridynamics to determine the ice loads for ship navigating in level ice. Convergence analysis of threedimensional specimen with tensile and compression loading... | Find, read cite all research you need Tech Science Press

The global navigation satellite system (GNSS) wave buoys currently in use can measure ocean surface waves but have major drawbacks regarding their real-time high-precision application due to the communication burden and high differential correction service costs; these issues heavily limited large-scale deployment of GNSS globally. In this work, we propose a low-cost centimeter-level precise measurement method using onboard variometric velocities segment parameter retrievals. proposed novel...

Only relying on a single satellite cannot ensure the wide coverage, low delay, and high communication quality at same time. Thus, novel cooperative two-layer network architecture is proposed in this paper. In architecture, centralized unit (CU) control plane that does not require real-time performance deployed geosynchronous earth orbit satellite, while CU-user distributed delay capacity are (LEO) closer to user equipment (UE). The cooperates with conventional terrestrial system provide...

Global Navigation Satellite System-Acoustic (GNSS-A) technology has been widely used in ocean engineering and environmental science. Accurate sound travel time modeling is essential for GNSS-A seafloor positioning. Currently, half of the two-way (TWTT) as an approximation one-way (OWTT). In this work, error approximate OWTT investigated under different survey configurations, a sequential positioning method using extended Kalman filter (EKF) developed to investigate impact modeling....

The yaw attitudes of Global Positioning System (GPS) satellites are critical to both satellite antenna phase centres and the wind-up corrections. However, nominal attitude GPS can barely be maintained during eclipse seasons. Thus, several models have been developed by International GNSS Service Analysis Centres (IGS ACs) avoid positioning degradation caused non-nominal attitudes. Based on analysis strategy each AC, modelled is compared with one, residuals Precise Point (PPP) investigated...

The acquisition of a 3D displacement field can help to understand the crustal deformation pattern seismogenic faults and deepen understanding earthquake nucleation. data for extraction are usually from GPS/interferometric synthetic aperture radar (InSAR) observations, direct solution method is adopted. We proposed an iterative least squares virtual observation (VOILS) based on maximum posteriori estimation criterion Bayesian theorem correct errors caused by GPS interpolation process....

Atmospheric water vapor plays an essential role in climate change and weather forecasting. However, monitoring with high spatial temporal resolutions remains a challenge, especially over ocean regions where observations are insufficient. Shipborne global navigation satellite systems (GNSSs) contribute to enriching measurements oceans also can help validate observations. Due the lack of long-time serial observations, performance shipborne GNSS-derived precipitable (PWV) is inadequately...

Water vapor over oceans is significant for numerical weather prediction (NWP) and climate research. Ocean platform-based global navigation satellite system (GNSS) which can sense the atmospheric water becoming an important supplement measurements oceans. However, application of ocean GNSS meteorology normally based on geodetic receivers, implies high cost hardware. In this contribution, we investigate potential retrieving real-time with a low-cost receiver (u-blox F9P), (Trimble NetR9) also...

Abstract As an attractive technique for measuring water vapor, the Global Navigation Satellite System (GNSS) faces additional challenges in dynamic applications such as open sea. We present a new method of retrieving precipitable vapor (PWV) based on GNSS multi‐antenna precise point positioning (PPP), which uses data from multiple antennas and incorporates constraints known baseline vector common tropospheric delay. The 4‐day shipborne experiment along China coast demonstrates that...

The Global Navigation Satellite System (GNSS) occultation receiver onboard the China Seismo-Electromagnetic (CSES) can provide dual-frequency observations for both GPS and BDS-2 satellites. In this study, data quality orbit determination performance of CSES are assessed. Severe loss about 30% is observed in P2/L2 data, resulting only 11% epochs possessing six to eight useful Due fewer channels being allocated BDS signals, less than 5% have more three Precise (POD) firstly carried out using...