We investigate the long-term performance and improvement of high-rate multiconstellation Global Navigation Satellite System (GNSS) or multi-GNSS attitude determination in a dynamical environment evaluate how much each GNSS contributes to such an with applications land vehicle navigation. build multiantenna system three nondedicated receivers conduct two experiments quad-constellations GNSS-friendly GNSS-challenged environments on January 19 23, 2018, respectively. A high-grade inertial...

The combination of nonlocal grouping and transformed domain filtering has led to the state-of-the-art denoising techniques. In this paper, we extend line study synthetic aperture radar (SAR) images based on clustering noisy image into disjoint local regions with similar spatial structure each region by linear minimum mean-square error (LMMSE) in principal component analysis (PCA) domain. Both are performed patches. For clustering, reduce dimensionality resist influence noise, several leading...

This paper presents a semi-automated method for shoreline extraction from RADARSAT-2 intensity imagery. First, preprocessing is applied to enhance the contrast of SAR image. Second, thresholding combined with morphological filtering employed segment image into land and sea. Third, narrow band level set segmentation implemented refine result. In last step, filters are utilized eliminate any remaining spurious segments. Boundaries between sea delineated shorelines based on Experiment images...

High-rate GNSS positioning has been widely investigated and applied in science engineering. We extend it to high-rate attitude determination under a multi-GNSS constellation. A series of experiments conducted on platform with three 50 Hz geodetic receivers two high-grade inertial measurement units (IMU). The solutions are computed for each the systems combined constellation by either using short baselines correct ambiguity resolution or precise point (PPP) compared IMU measurements. In case...

Abstract We present a new method of integrating Global Positioning System (GPS) and accelerometer data for high‐rate seismogeodesy. This is based on the GPS variometric approach which can obtain seismic waves in real time using only readily available broadcast products single receiver. Collocated 1‐Hz 200‐Hz from 2016 M W 7.8 Kaikōura earthquake were analyzed to verify effectiveness this method. Results reveal that provide broadband more accurate velocities displacements qualified detect P...

Abstract Difference methods have been routinely used to compute velocity and acceleration from precise positioning with global navigation satellite systems (GNSS). A low sampling rate (say a not greater than 1 Hz, for example) has always implicitly assumed applicability of the methods, because random measurement errors are significantly amplified, either proportional in case or square-proportional acceleration. Direct consequences distortion computed waveforms failure obtain almost...

Abstract Rapid response to destructive tsunami and seismic events requires rapid determination of the earthquake magnitude. We propose a new method that employs peak ground velocities (PGVs) derived from Global Navigation Satellite System (GNSS) data estimate magnitudes. With total 1434 records 22 as constraints, we perform regression obtain PGV scaling law for magnitude determination. The advantage is PGVs are extracted GNSS velocity waveforms, which can be easily computed using broadcast...

A moment magnitude Mw9.0 earthquake hit northeastern Japan at 14:46:18 (Japan Standard Time), March 11, 2011. We have obtained 1 s precise point positioning solutions for 1198 GEONET stations. Although GPS position time series been routinely investigated and used as waveforms dynamic inversion of earthquakes, we focus on exploring the spatial displacement features stations this earthquake. movie inspection high-rate leads us to find that 76.21% in Japanese islands subsided suddenly within...

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...

In recent years, very high-rate (10–50 Hz) Global Navigation Satellite System (GNSS) has gained a rapid development and been widely applied in seismology, natural hazard early warning system structural monitoring. However, existing studies on stochastic models of GNSS observations are limited to sampling rates not higher than 1 Hz. To support applications, we assess the precisions, cross correlations time (50 Positioning (GPS)/BeiDou code phase observations. The method least-squares variance...

SUMMARY High-rate global navigation satellite system (GNSS) has emerged as an effective method to recover seismic waveforms without saturation and drifts, but it the limitation of relatively lower sampling rate higher noise level compared instruments. In this study, we present a new seismogeodetic by integrating GNSS accelerometer data obtain optimal real-time waveforms. Unlike traditional integration methods based on techniques relative positioning or precise point positioning, uses time...

Abstract Although global navigation satellite systems (GNSS) have been routinely applied to determine attitudes, there exists no literature on determining angular velocity and/or acceleration from GNSS. Motivated by the invention of computerized accelerometers correspondence author and following success accurately recovering translational waveforms very high-rate GNSS precise positioning Xu his collaborators in 2021, we propose concept gyroscopes reconstruct attitudes applying regularization...

MODIS 1B data preprocessing consists of "bowtie" effect elimination and geometric correction. The paper proposes a fast algorithm. First, partition the input image into small sub-images without effect. Secondly, do correction to each sub-image. Finally, mosaic sub-image in output coordinate system eliminate process. proposed algorithm shows both better performance faster speed. For massive preprocessing, parallel method based on this above is further proposed. Analysis that real-time for can...

Stability of the tidal flat in silt-muddy coast is ability to keep its terrain from erosion under ocean dynamic processes. Evaluating stability one most important issues insediment dynamics research field , and has been attached more importance. Dongsha Sandbank largest sandbanks radial sand ridges, serves as an barrier inner sandbank a direct impact on process Tiaozini merging into mainland. To evaluate will provide guidance for coastal zone environmental protection (such protection, etc.)...