Scientific and Operational Roadmap for Fiducial Reference Measurements in Satellite Altimetry Calibration & Validation

2019 ◽  
pp. 105-109 ◽  
Author(s):  
Stelios P. Mertikas ◽  
Craig Donlon ◽  
Rob Cullen ◽  
Achilles Tripolitsiotis
Keyword(s):  
Satellite Altimetry ◽  
Reference Measurements

scholarly journals An Action Plan Towards Fiducial Reference Measurements for Satellite Altimetry

2019 ◽  
Vol 11 (17) ◽  
pp. 1993 ◽  
Author(s):  
Mertikas ◽  
Donlon ◽  
Vuilleumier ◽  
Cullen ◽  
Féménias ◽  
...  
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Action Plan ◽  
European Space Agency ◽  
Earth Observation ◽  
Sea Level Changes ◽  
Space Agency ◽  
Historic Record ◽  
To Come ◽  
Reference Measurements

Satellite altimeters have been producing, as of 1992, an amazing and historic record of sea level changes. As Europe moves into full operational altimetry, it has become imperative that the quality of these monitoring signals with their uncertainties should be controlled, fully and properly descripted, but also traced and connected to undisputable standards and units. Excellent quality is the foundation of these operational services of Europe in altimetry. In line with the above, the strategy of the Fiducial Reference Measurements for Altimetry (FRM4ALT) has been introduced to address and to achieve reliable, long-term, consistent, and undisputable satellite altimetry products for Earth observation and for sea-level change monitoring. FRM4ALT has been introduced and implemented by the European Space Agency in an effort to reach a uniform and absolute standardization for calibrating satellite altimeters. This paper examines the problem and the need behind the FRM4ALT principle to achieve an objective Earth observation. Secondly, it describes the expected FRM products and services which are to come into being out of this new observational strategy. Thirdly, it outlines the technology and the services required for reaching this goal. And finally, it elaborates upon the necessary resources, skills, partnerships, and facilities for establishing FRM standardization for altimetry.

Fiducial Reference Measurements for Satellite Altimetry Calibration: The Constituents

2019 ◽  
pp. 1-6 ◽  
Author(s):  
Stelios P. Mertikas ◽  
Craig Donlon ◽  
Pierre Féménias ◽  
Rob Cullen ◽  
Demitris Galanakis ◽  
...  
Keyword(s):  
Satellite Altimetry ◽  
Reference Measurements

A new path loss model based on the volumetric occupancy rate for the pine forests at 5G frequency band

2020 ◽  
pp. 1-10
Author(s):  
Abdullah Genc
Keyword(s):  
Path Loss ◽  
Forest Area ◽  
Occupancy Rate ◽  
Loss Model ◽  
Path Loss Model ◽  
Model Based ◽  
Proposed Model ◽  
Pine Trees ◽  
Foliage Density ◽  
Reference Measurements

Abstract In this paper, a new empirical path loss model based on frequency, distance, and volumetric occupancy rate is generated at the 3.5 and 4.2 GHz in the scope of 5G frequency bands. This study aims to determine the effect of the volumetric occupancy rate on path loss depending on the foliage density of the trees in the pine forest area. Using 4.2 GHz and the effect of the volumetric occupancy rate contributes to the literature in terms of novelty. Both the reference measurements to generate a model and verification measurements to verify the proposed models are conducted in three different regions of the forest area with double ridged horn antennas. These regions of the artificial forest area consist of regularly sorted and identical pine trees. Root mean square error (RMSE) and R-squared values are calculated to evaluate the performance of the proposed model. For 3.5 and 4.2 GHz, while the RMSEs are 3.983 and 3.883, the values of R-squared are 0.967 and 0.963, respectively. Additionally, the results are compared with four path loss models which are commonly used in the forest area. The proposed one has the best performance among the other models with values 3.98 and 3.88 dB for 3.5 and 4.2 GHz.

scholarly journals Reference Measurements in Developing UAV Systems for Detecting Pests, Weeds, and Diseases

2021 ◽  
Vol 13 (7) ◽  
pp. 1238
Author(s):  
Jere Kaivosoja ◽  
Juho Hautsalo ◽  
Jaakko Heikkinen ◽  
Lea Hiltunen ◽  
Pentti Ruuttunen ◽  
...  
Keyword(s):  
Reference Data ◽  
Measurement Techniques ◽  
Synthetic Data ◽  
Ground Truth ◽  
Precision Farming ◽  
Aerial Imaging ◽  
Aerial Vehicle ◽  
Uav Images ◽  
Reference Measurements

The development of UAV (unmanned aerial vehicle) imaging technologies for precision farming applications is rapid, and new studies are published frequently. In cases where measurements are based on aerial imaging, there is the need to have ground truth or reference data in order to develop reliable applications. However, in several precision farming use cases such as pests, weeds, and diseases detection, the reference data can be subjective or relatively difficult to capture. Furthermore, the collection of reference data is usually laborious and time consuming. It also appears that it is difficult to develop generalisable solutions for these areas. This review studies previous research related to pests, weeds, and diseases detection and mapping using UAV imaging in the precision farming context, underpinning the applied reference measurement techniques. The majority of the reviewed studies utilised subjective visual observations of UAV images, and only a few applied in situ measurements. The conclusion of the review is that there is a lack of quantitative and repeatable reference data measurement solutions in the areas of mapping pests, weeds, and diseases. In addition, the results that the studies present should be reflected in the applied references. An option in the future approach could be the use of synthetic data as reference.

scholarly journals An Analysis of Vertical Crustal Movements along the European Coast from Satellite Altimetry, Tide Gauge, GNSS and Radar Interferometry

2021 ◽  
Vol 13 (11) ◽  
pp. 2173
Author(s):  
Kamil Kowalczyk ◽  
Katarzyna Pajak ◽  
Beata Wieczorek ◽  
Bartosz Naumowicz
Keyword(s):  
Time Series ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Measurement Techniques ◽  
Radar Interferometry ◽  
Vertical Movements ◽  
Persistent Scatterer ◽  
Gnss Time Series ◽  
Vertical Crustal Movements ◽  
European Coast

The main aim of the article was to analyse the actual accuracy of determining the vertical movements of the Earth’s crust (VMEC) based on time series made of four measurement techniques: satellite altimetry (SA), tide gauges (TG), fixed GNSS stations and radar interferometry. A relatively new issue is the use of the persistent scatterer InSAR (PSInSAR) time series to determine VMEC. To compare the PSInSAR results with GNSS, an innovative procedure was developed: the workflow of determining the value of VMEC velocities in GNSS stations based on InSAR data. In our article, we have compiled 110 interferograms for ascending satellites and 111 interferograms for descending satellites along the European coast for each of the selected 27 GNSS stations, which is over 5000 interferograms. This allowed us to create time series of unprecedented time, very similar to the time resolution of time series from GNSS stations. As a result, we found that the obtained accuracies of the VMEC determined from the PSInSAR are similar to those obtained from the GNSS time series. We have shown that the VMEC around GNSS stations determined by other techniques are not the same.

scholarly journals Studying Sea Level Variability in Indonesia Sea Based on Satellite Altimetry

2020 ◽  
Vol 618 ◽  
pp. 012040
Author(s):  
Dina A Sarsito ◽  
Muhammad Syahrullah ◽  
Dudy D Wijaya ◽  
Dhota Pradipta ◽  
Heri Andreas
Keyword(s):  
Sea Level ◽  
Satellite Altimetry ◽  
Sea Level Variability

Renal function measurements from MR renography and a simplified multicompartmental model

2007 ◽  
Vol 292 (5) ◽  
pp. F1548-F1559 ◽  
Author(s):  
Vivian S. Lee ◽  
Henry Rusinek ◽  
Louisa Bokacheva ◽  
Ambrose J. Huang ◽  
Niels Oesingmann ◽  
...  
Keyword(s):  
Low Dose ◽  
Random Noise ◽  
Compartment Model ◽  
Parameter Estimates ◽  
Imaging Data ◽  
Tracer Injection ◽  
Multicompartmental Model ◽  
Enhancement Curve ◽  
Reference Measurements ◽  
Single Kidney

The purpose of this study was to determine the accuracy and sources of error in estimating single-kidney glomerular filtration rate (GFR) derived from low-dose gadolinium-enhanced T1-weighted MR renography. To analyze imaging data, MR signal intensity curves were converted to concentration vs. time curves, and a three-compartment, six-parameter model of the vascular-nephron system was used to analyze measured aortic, cortical, and medullary enhancement curves. Reliability of the parameter estimates was evaluated by sensitivity analysis and by Monte Carlo analyses of model solutions to which random noise had been added. The dominant sensitivity of the medullary enhancement curve to GFR 1–4 min after tracer injection was supported by a low coefficient of variation in model-fit GFR values (4%) when measured data were subjected to 5% noise. These analyses also showed the minimal effects of bolus dispersion in the aorta on parameter reliability. Single-kidney GFR from MR renography analyzed by the three-compartment model (4.0–71.4 ml/min) agreed well with reference measurements from 99mTc-DTPA clearance and scintigraphy ( r = 0.84, P < 0.001). Bland-Altman analysis showed an average difference of 11.9 ml/min (95% confidence interval = 5.8–17.9 ml/min) between model and reference values. We conclude that a nephron-based multicompartmental model can be used to derive clinically useful estimates of single-kidney GFR from low-dose MR renography.

Sign in / Sign up

Export Citation Format

Share Document