Enabling ambiguity resolution in CSRS‐PPP

Banville, Simon; Hassen, Elyes; Lamothe, Philippe; Farinaccio, Justin; Donahue, Brian; Mireault, Yves; Goudarzi, Mohammad Ali; Collins, Paul; Ghoddousi‐Fard, Reza; Kamali, Omid

doi:10.1002/navi.423

Cited by 36 publications

(31 citation statements)

References 34 publications

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“…(3) Results from CSRS-PPP [33,34] are sufficiently accurate for validation of ICESat-2 surface height determination and morphological characteristics, as will be detailed in the following sections, while most likely significantly less accurate than positions differentially corrected with a base station. The CSRS post-processing uses precise satellite orbits, clock and bias corrections from a global network of receivers.…”

Section: Resultsmentioning

confidence: 99%

“…(1) Kinematic GPS data collection with differential correction using base and rover data (summer 2018) (2) Real-time kinematic (RTK) GPS data collection using base and rover data (summer 2018) (3) Kinematic GPS data collection with differential correction of rover data using Natural Resources Canada Spatial Reference System Precise Point Positioning (CSRS-PPP, [33,34]), (summer 2019)…”

Section: Scientific Motivation and Experimentsmentioning

confidence: 99%

“…In 2019, the GPS base station malfunctioned or was set incorrectly, recording only 15-second data, thus the differential correction applied to the 2019 GPS rover data uses Spatial Reference System Precise Point Positioning (CSRS-PPP), a service provided by Canadian Geodetic Survey, Natural Resources Canada, for post processing [33,34]. This situation yields an unintentional third type of experiment, whose results may be of interest for flights where a base station cannot be placed.…”

Section: Scientific Motivation and Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Airborne Validation of ICESat-2 ATLAS Data over Crevassed Surfaces and Other Complex Glacial Environments: Results from Experiments of Laser Altimeter and Kinematic GPS Data Collection from a Helicopter over a Surging Arctic Glacier (Negribreen, Svalbard)

et al. 2022

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The topic of this paper is the airborne evaluation of ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) measurement capabilities and surface-height-determination over crevassed glacial terrain, with a focus on the geodetical accuracy of geophysical data collected from a helicopter. To obtain surface heights over crevassed and otherwise complex ice surface, ICESat-2 data are analyzed using the density-dimension algorithm for ice surfaces (DDA-ice), which yields surface heights at the nominal 0.7 m along-track spacing of ATLAS data. As the result of an ongoing surge, Negribreen, Svalbard, provided an ideal situation for the validation objectives in 2018 and 2019, because many different crevasse types and morphologically complex ice surfaces existed in close proximity. Airborne geophysical data, including laser altimeter data (profilometer data at 905 nm frequency), differential Global Positioning System (GPS), Inertial Measurement Unit (IMU) data, on-board-time-lapse imagery and photographs, were collected during two campaigns in summers of 2018 and 2019. Airborne experiment setup, geodetical correction and data processing steps are described here. To date, there is relatively little knowledge of the geodetical accuracy that can be obtained from kinematic data collection from a helicopter. Our study finds that (1) Kinematic GPS data collection with correction in post-processing yields higher accuracies than Real-Time-Kinematic (RTK) data collection. (2) Processing of only the rover data using the Natural Resources Canada Spatial Reference System Precise Point Positioning (CSRS-PPP) software is sufficiently accurate for the sub-satellite validation purpose. (3) Distances between ICESat-2 ground tracks and airborne ground tracks were generally better than 25 m, while distance between predicted and actual ICESat-2 ground track was on the order of 9 m, which allows direct comparison of ice-surface heights and spatial statistical characteristics of crevasses from the satellite and airborne measurements. (4) The Lasertech Universal Laser System (ULS), operated at up to 300 m above ground level, yields full return frequency (400 Hz) and 0.06–0.08 m on-ice along-track spacing of height measurements. (5) Cross-over differences of airborne laser altimeter data are −0.172 ± 2.564 m along straight paths, which implies a precision of approximately 2.6 m for ICESat-2 validation experiments in crevassed terrain. (6) In summary, the comparatively light-weight experiment setup of a suite of small survey equipment mounted on a Eurocopter (Helicopter AS-350) and kinematic GPS data analyzed in post-processing using CSRS-PPP leads to high accuracy repeats of the ICESat-2 tracks. The technical results (1)–(6) indicate that direct comparison of ice-surface heights and crevasse depths from the ICESat-2 and airborne laser altimeter data is warranted. Numerical evaluation of height comparisons utilizes spatial surface roughness measures. The final result of the validation is that ICESat-2 ATLAS data, analyzed with the DDA-ice, facilitate surface-height determination over crevassed terrain, in good agreement with airborne data, including spatial characteristics, such as surface roughness, crevasse spacing and depth, which are key informants on the deformation and dynamics of a glacier during surge.

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Section: Resultsmentioning

confidence: 99%

Section: Scientific Motivation and Experimentsmentioning

confidence: 99%

Section: Scientific Motivation and Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Airborne Validation of ICESat-2 ATLAS Data over Crevassed Surfaces and Other Complex Glacial Environments: Results from Experiments of Laser Altimeter and Kinematic GPS Data Collection from a Helicopter over a Surging Arctic Glacier (Negribreen, Svalbard)

et al. 2022

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“…We used the Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP) online web service of the Natural Resources of Canada to provide the daily solutions. The service provides Precise Point Absolute Positioning (PPP) for data prior to 2018, and PPP with reliable integer ambiguity resolution for GPS (PPP-AR) from 2018 in advance (Banville, 2020). Both methods allow estimating the station coordinates for the specific epoch using accurate satellite orbit and clock information from the International GPS Service, from the absolute calibration models of the IGS antenna phase-center and from the elimination of systematic errors through the accurate modelling of various error sources, such as ionospheric and tropospheric delays, Earth tide and ocean tide loading, the latter correction uses the GOT4.10 model (Ray, 2013;1999).…”

Section: Geological Settingmentioning

confidence: 99%

2D strain rate and ground deformation modelling from continuous and survey mode GNSS data in El Hierro, Canary Islands

Arnoso

Riccardi

Tammaro

et al. 2022

Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022

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We present a study of the deformation pattern in El Hierro Island through the analysis of GNSS data from surveys carried out between 2015 and 2019 as well as continuous data. The last eruption in El Hierro occurred under the sea on the south rift, lasted from October 2011 to March 2012, and it was preceded by intense seismic activity and nearly 5 cm ground inflation. After this eruptive cycle, further magmatic intrusions were detected, from June 2012 to March 2014, associated to intense seismic swarms and inflation (about 22 cm of uplift). Nevertheless, these magmatic intrusions did not culminate in any eruption. Following these post-eruptive episodes, the seismic activity became less intense. Thus, for the period of this study, about 500 earthquakes with magnitude ranging from mbLG 2 to mbLG 3.9 were recorded, the ground deformation measured is of lower magnitude, still remaining a slight uplift trend in the GNSS stations up to 2017 and followed by a slight subsidence of about 1.5 cm between 2017-2019. Our purpose is to explain the ground displacements measured and the earthquake occurrence in terms of geodynamics and seismotectonic activity along the island, for the period 2015-2019. Firstly, we retrieved the geodetic velocities from the GNSS daily solutions. Secondly, we computed the 2D infinitesimal strain rates from the velocities through a triangular segmentation approach to map the deformation pattern along the respective GNSS surveys.

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“…The report of CSRS‐PPP positioning results includes a “Fixed Ambiguities” for each solution, which represents the ambiguity resolved percentage (ARP) of GPS kinematic PPP (PPP‐ARP). The ARP is defined as the number of carrier‐phase observations with fixed ambiguities divided by the total number of phase measurements (Banville et al., 2021). Previous study indicated that the reference station density, observation session length, ionospheric activity, geomagnetic latitude of receiver station, and the selection of PPP AR products all have an impact on PPP‐AR (Zhang & Li, 2012).…”

Section: Introductionmentioning

confidence: 99%

Studying the Fixing Rate of GPS PPP Ambiguity Resolution Under Different Geomagnetic Storm Intensities

Luo,

Chen,

et al. 2023

Space Weather

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Global Positioning System (GPS) Precise Point Positioning (PPP) with correct fixing ambiguity resolution (AR) can reach cm‐mm level positioning accuracy. However, this accuracy can be degraded by the geomagnetic storm effects. To comprehensively investigate the ambiguity resolved percentage (ARP) of GPS kinematic PPP, referred to as PPP‐ARP, under different intensities of geomagnetic storms, based on the Natural Resources Canada's Canadian Spatial Reference System (CSRS) PPP, this study for the first time gives the correlation between the PPP‐ARP and storm intensity using 67 storms occurred in the past 5 years of 2018–2022. Experimental results indicate that the PPP‐ARP decreases gradually as the increase of geomagnetic storm intensity. Under quiet and low geomagnetic conditions (Dstmin > −50 nT), the PPP‐ARP of global GNSS stations can achieve more than 96%, while these during strong storms (Dstmin ≤ −100 nT) are generally lower than 90.0%, especially for the PPP‐ARP of some stations located at low latitudes which are lower than 40.0%. The mechanism of PPP‐ARP decrease under geomagnetic storms is mainly due to the cycle slips and even loss of lock of GNSS signals caused by the storms induced ionospheric disturbances and scintillations. In addition, different from many previous studies, we found that the CSRS‐PPP with AR can achieve good positioning accuracy (3D RMS <0.2 m) even under strong geomagnetic storms.

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Enabling ambiguity resolution in CSRS‐PPP

Cited by 36 publications

References 34 publications

Airborne Validation of ICESat-2 ATLAS Data over Crevassed Surfaces and Other Complex Glacial Environments: Results from Experiments of Laser Altimeter and Kinematic GPS Data Collection from a Helicopter over a Surging Arctic Glacier (Negribreen, Svalbard)

Airborne Validation of ICESat-2 ATLAS Data over Crevassed Surfaces and Other Complex Glacial Environments: Results from Experiments of Laser Altimeter and Kinematic GPS Data Collection from a Helicopter over a Surging Arctic Glacier (Negribreen, Svalbard)

2D strain rate and ground deformation modelling from continuous and survey mode GNSS data in El Hierro, Canary Islands

Studying the Fixing Rate of GPS PPP Ambiguity Resolution Under Different Geomagnetic Storm Intensities

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