scholarly journals Application of signal correction for Sphenophorus levis control and higher quality production in mechanized harvesting of sugarcane ratoon

2019 ◽  
pp. 1936-1942
Author(s):  
Rafael Henrique de Freitas Noronha ◽  
Mailson Freire de Oliveira ◽  
Arthur Laurentiz Mendes ◽  
André Ferreira Damasceno ◽  
Cristiano Zerbato ◽  
...  
Keyword(s):  
Control Charts ◽  
Satellite System ◽  
Control Analysis ◽  
Statistical Process ◽  
Automatic Steering ◽  
Cutting Operation ◽  
Sphenophorus Levis ◽  
The Mean ◽  
Global Navigation Satellite ◽  
Sugarcane Ratoon

Higher quality mechanized agricultural operations can be achieved with the use of the Global Navigation Satellite System (GNSS) signal positioning tools (correction signals), allowing a higher accuracy, which is extremely important to reduce operating costs and waste of inputs, in addition to allowing a more effective pest control. Thus, the aim of this study was to evaluate the behavior of the mean execution error of the positioning and pass-to-pass design in the operation of sugarcane ratoon cutting and insecticide application. Furthermore, the efficiency of controlling Sphenophorus levis through non-automatic steering (NS) and use of autopilot (RTX and RTK correction signals) in a sugarcane production plot of an experimental area located in the city of Motuca, SP, Brazil were evaluated for a total of 150 points by means of the statistical process control, analysis of variance, and descriptive statistics. Fipronil was the insecticide used for S. levis control. The evaluations consisted of the measurement of the mean execution error of the project during tractor operation in ten strides and five replications, in addition to the pass-to-pass (parallelism error) error between strides of the tractor-ratoon cutter assembly. In all strides, the mean execution error and mean error of the tractor-seeder assembly were within both the acceptable limit and the stipulated by the signal manufacturer, with values lower than 3.8 cm. The control charts were efficient to evaluate the behavior of RTX signal quality, facilitating the visualization within the limits of the project execution errors and pass-to-pass, in addition to contributing with an S. levis control 27.16% higher than the conventional control in the cutting operation of sugarcane ratoon.

scholarly journals Sea Topography of the Ionian and Adriatic Seas Using Repeated GNSS Measurements

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 812
Author(s):  
Sotiris Lycourghiotis
Keyword(s):  
Satellite System ◽  
Geoid Model ◽  
Sea Surface Topography ◽  
Mean Sea Surface ◽  
The Mean ◽  
A New Technique ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Constant Slope ◽  
Ionian And Adriatic Seas

The mean sea surface topography of the Ionian and Adriatic Seas has been determined. This was based on six-months of Global Navigation Satellite System (GNSS) measurements which were performed on the Ionian Queen (a ship). The measurements were analyzed following a double-path methodology based on differential GNSS (D-GNSS) and precise point positioning (PPP) analysis. Numerical filtering techniques, multi-parametric accuracy analysis and a new technique for removing the meteorological tide factors were also used. Results were compared with the EGM96 geoid model. The calculated differences ranged between 0 and 48 cm. The error of the results was estimated to fall within 3.31 cm. The 3D image of the marine topography in the region shows a nearly constant slope of 4 cm/km in the N–S direction. Thus, the effectiveness of the approach “repeated GNSS measurements on the same route of a ship” developed in the context of “GNSS methods on floating means” has been demonstrated. The application of this approach using systematic multi-track recordings on conventional liner ships is very promising, as it may open possibilities for widespread use of the methodology across the world.

scholarly journals Determination of Conversion Constant between Lagos Datum and Niger Delta Mean Lower Low Water Datum and their Horizontal and Vertical Accuracy Standards using GNSS Observations

2018 ◽  
Vol 2 (1) ◽  
pp. 56-68
Author(s):  
M. O. Ehigiator ◽  
S. O. Oladosu
Keyword(s):  
Niger Delta ◽  
Satellite System ◽  
Constant Factor ◽  
Common Mean ◽  
Height Determination ◽  
The Mean ◽  
Vertical Accuracy ◽  
Global Navigation Satellite ◽  
Gnss Observations

With the use of Global Navigation Satellite System (GNSS) technology, it is now possible to determine the position of points in 3D coordinates systems. Lagos datum is the most common Mean Sea Level used in most parts of Nigeria. In Niger Delta, for instance Warri and its environs, the most commonly used datum for height determination is the Mean Lower Low Water Datum. It then becomes necessary to determine a constant factor for conversion between the two datum when the need arises as both are often encountered during Geomatics Engineering field operations. In this paper, the constant to be applied in converting between both datum was determined. The constant was found to be 17.79m. The horizontal and vertical accuracy standard was also determined as well as the stack maps.

Algorithm Research Using GNSS-TEC Data to Calibrate TEC Calculated by the IRI-2016 Model over China

2021 ◽  
Vol 13 (19) ◽  
pp. 4002
Author(s):  
Wen Zhang ◽  
Xingliang Huo ◽  
Yunbin Yuan ◽  
Zishen Li ◽  
Ningbo Wang
Keyword(s):  
Mean Absolute Error ◽  
Absolute Error ◽  
Satellite System ◽  
Electron Content ◽  
Iri Model ◽  
Ionospheric Electron Content ◽  
The Mean ◽  
Spatial Grid ◽  
Global Navigation Satellite ◽  
Gnss Data

The International Reference Ionosphere (IRI) is an empirical model widely used to describe ionospheric characteristics. In the previous research, high-precision total ionospheric electron content (TEC) data derived from global navigation satellite system (GNSS) data were used to adjust the ionospheric global index IG12 used as a driving parameter in the standard IRI model; thus, the errors between IRI-TEC and GNSS-TEC were minimized, and IRI-TEC was calibrated by modifying IRI with the updated IG12 index (IG-up). This paper investigates various interpolation strategies for IG-up values calculated from GNSS reference stations and the calibrated TEC accuracy achieved using the modified IRI-2016 model with the interpolated IG-up values as driving parameters. Experimental results from 2015 and 2019 show that interpolating IG-up with a 2.5° × 5° spatial grid and a 1-h time resolution drives IRI-2016 to generate ionospheric TEC values consistent with GNSS-TEC. For 2015 and 2019, the mean absolute error (MAE) of the modified IRI-TEC is improved by 78.57% and 77.42%, respectively, and the root mean square error (RMSE) is improved by 78.79% and 77.14%, respectively. The corresponding correlations of the linear regression between GNSS-TEC and the modified IRI-TEC are 0.986 and 0.966, more than 0.2 higher than with the standard IRI-TEC.

scholarly journals A comparison of methods to estimate vertical land motion trends from GNSS and altimetry at tide gauge stations

Ocean Science ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 187-204 ◽  
Author(s):  
Marcel Kleinherenbrink ◽  
Riccardo Riva ◽  
Thomas Frederikse
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Tide Gauge ◽  
Satellite System ◽  
Vertical Land Motion ◽  
Correlation Threshold ◽  
The Mean ◽  
Highly Correlated ◽  
Global Navigation Satellite ◽  
Along Track

Abstract. Tide gauge (TG) records are affected by vertical land motion (VLM), causing them to observe relative instead of geocentric sea level. VLM can be estimated from global navigation satellite system (GNSS) time series, but only a few TGs are equipped with a GNSS receiver. Hence, (multiple) neighboring GNSS stations can be used to estimate VLM at the TG. This study compares eight approaches to estimate VLM trends at 570 TG stations using GNSS by taking into account all GNSS trends with an uncertainty smaller than 1 mm yr−1 within 50 km. The range between the methods is comparable with the formal uncertainties of the GNSS trends. Taking the median of the surrounding GNSS trends shows the best agreement with differenced altimetry–tide gauge (ALT–TG) trends. An attempt is also made to improve VLM trends from ALT–TG time series. Only using highly correlated along-track altimetry and TG time series reduces the SD of ALT–TG time series by up to 10 %. As a result, there are spatially coherent changes in the trends, but the reduction in the root mean square (RMS) of differences between ALT–TG and GNSS trends is insignificant. However, setting correlation thresholds also acts like a filter to remove problematic TG time series. This results in sets of ALT–TG VLM trends at 344–663 TG locations, depending on the correlation threshold. Compared to other studies, we decrease the RMS of differences between GNSS and ALT–TG trends (from 1.47 to 1.22 mm yr−1), while we increase the number of locations (from 109 to 155), Depending on the methods the mean of differences between ALT–TG and GNSS trends vary between 0.1 and 0.2 mm yr−1. We reduce the mean of the differences by taking into account the effect of elastic deformation due to present-day mass redistribution. At varying ALT–TG correlation thresholds, we provide new sets of trends for 759 to 939 different TG stations. If both GNSS and ALT–TG trend estimates are available, we recommend using the GNSS trend estimates because residual ocean signals might correlate over long distances. However, if large discrepancies ( > 3 mm yr−1) between the two methods are present, local VLM differences between the TG and the GNSS station are likely the culprit and therefore it is better to take the ALT–TG trend estimate. GNSS estimates for which only a single GNSS station and no ALT–TG estimate are available might still require some inspection before they are used in sea level studies.

scholarly journals Analysis of BDS/GPS Signals’ Characteristics and Navigation Accuracy for a Geostationary Satellite

2021 ◽  
Vol 13 (10) ◽  
pp. 1967
Author(s):  
Meng Wang ◽  
Tao Shan ◽  
Wanwei Zhang ◽  
Hao Huan
Keyword(s):  
Real Time ◽  
High Sensitivity ◽  
The United States ◽  
Satellite System ◽  
Least Square ◽  
Navigation Satellite ◽  
Position Accuracy ◽  
The Mean ◽  
Single Epoch ◽  
Global Navigation Satellite

The utilization of Global Navigation Satellite System (GNSS) is becoming an attractive navigation approach for geostationary orbit (GEO) satellites. A high-sensitivity receiver compatible with Global Position System (GPS) developed by the United States and BeiDou Navigation Satellite System (BDS) developed by China has been used in a GEO satellite named TJS-5 to demonstrate feasibility of real-time navigation. According to inflight data, the GNSS signal characteristics including availability, position dilution of precision (PDOP), carrier-to-noise ratio (C/N0), observations quantity and accuracy are analyzed. The mean number of GPS and GPS + BDS satellites tracked are 7.4 and 11.7 and the mean PDOP of GPS and GPS + BDS are 10.24 and 3.91, respectively. The use of BDS significantly increases the number of available navigation satellites and improves the PDOP. The number of observations with respect to C/N0 is illustrated in detail. The standard deviation of the pseudorange noises are less than 4 m, and the corresponding carrier phase noises are mostly less than 8 mm. We present the navigation performance using only GPS observations and GPS + BDS observations combination at different weights through comparisons with the precision reference orbits. When GPS combined with BDS observations, the root mean square (RMS) of the single-epoch least square position accuracy can improve from 32.1 m to 16.5 m and the corresponding velocity accuracy can improve from 0.238 m/s to 0.165 m/s. The RMS of real-time orbit determination position accuracy is 5.55 m and the corresponding velocity accuracy is 0.697 mm/s when using GPS and BDS combinations. Especially, the position accuracy in x-axis direction reduced from 7.24 m to 4.09 m when combined GPS with BDS observations.

scholarly journals CONTRIBUTION TO THE SPC IMPLEMENTATION BY SELECTING AN APPROPRIATE VARIABLE CONTROL CHART

2021 ◽  
Vol 24 (1) ◽  
pp. 50-54
Author(s):  
Mite Tomov ◽  
◽  
Leonard Abazovski ◽  
Anastasija Ignjatovska ◽  
◽  
...  
Keyword(s):  
Control Chart ◽  
Control Charts ◽  
Mean Value ◽  
Practical Implementation ◽  
Statistical Process ◽  
Serial Production ◽  
Variable Control ◽  
Percentage Difference ◽  
The Mean ◽  
Distribution Type

The research in this paper contributes to the practical implementation of the Statistical Process Control (SPC), primarily in the serial production by selecting an appropriate variable control chart. The paper proposes a procedure algorithm where the deciding criteria used to select the variable control chart include: the data distribution type (whether an approximately normal distribution or not), the number of elements in the subgroup (n) for grouped data, the shift size value and the percentage difference between the shift size value and the mean value of the shifts calculated for each subgroup. The paper explains the proposed algorithm using examples with appropriately drawn control charts, which algorithm essentially represents an extension of the algorithm presented in ISO 7870-2:2013.

scholarly journals A comparison of data weighting methods to derive vertical land motion trends from GNSS and altimetry at tide gauge stations

2017 ◽  
Author(s):  
Marcel Kleinherenbrink ◽  
Riccardo Riva ◽  
Thomas Frederikse
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
Satellite System ◽  
Vertical Land Motion ◽  
Correlation Threshold ◽  
The Mean ◽  
Highly Correlated ◽  
Global Navigation Satellite ◽  
Along Track ◽  
Weighting Methods

Abstract. This study compares eight weighting techniques for Global Navigation Satellite System (GNSS)-derived Vertical Land Motion (VLM) trends at 570 tide gauge (TG) stations. The spread between the methods has a comparable size as the formal uncertainties of the GNSS trends. Taking the median of the surrounding GNSS trends shows the best agreement with differenced altimetry – tide gauge (ALT-TG) trends. An attempt is also made to improve VLM trends from ALT-TG time series. Only using highly correlated along-track altimetry and TG time series, reduces the standard deviation of ALT-TG time series up to 10 %. As a result, there are spatially coherent changes in the trends, but the reduction in the RMS of differences between ALT-TG and GNSS trends is insignificant. However, setting correlation thresholds also acts like a filter to remove problematic TG stations. This results in sets of ALT-TG VLM trends at 344–663 TG locations, depending on the correlation threshold. Compared to other studies, we decrease the RMS of differences between GNSS and ALT-TG trends (from 1.47 to 1.22 mm/yr), while we increase the number of locations (from 109 to 155), Depending on the weighting methods the mean of differences between ALT-TG and GNSS trends varies between 0.1–0.2 mm/yr. We reduce the mean of differences by taking into account the effect of elastic deformation due to present-day mass redistribution into account.

scholarly journals Monitoring the mean with least-squares support vector data description

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Edgard M. Maboudou-Tchao
Keyword(s):  
Least Squares ◽  
Statistical Process Control ◽  
Control Charts ◽  
Classification Problem ◽  
Support Vector ◽  
Support Vector Data Description ◽  
Vector Data ◽  
Statistical Process ◽  
Data Description ◽  
The Mean

Abstract: Multivariate control charts are essential tools in multivariate statistical process control (MSPC). “Shewhart-type” charts are control charts using rational subgroupings which are effective in the detection of large shifts. Recently, the one-class classification problem has attracted a lot of interest. Three methods are typically used to solve this type of classification problem. These methods include the k−center method, the nearest neighbor method, one-class support vector machine (OCSVM), and the support vector data description (SVDD). In industrial applications, like statistical process control (SPC), practitioners successfully used SVDD to detect anomalies or outliers in the process. In this paper, we reformulate the standard support vector data description and derive a least squares version of the method. This least-squares support vector data description (LS-SVDD) is used to design a control chart for monitoring the mean vector of processes. We compare the performance of the LS-SVDD chart with the SVDD and T2 chart using out-of-control Average Run Length (ARL) as the performance metric. The experimental results indicate that the proposed control chart has very good performance.

scholarly journals Large-scale map and 3D modelling of the Henryk Arctowski Polish Antarctic Station

Polar Record ◽  
2017 ◽  
Vol 53 (3) ◽  
pp. 280-288 ◽  
Author(s):  
Mariusz Pasik ◽  
Maria Elżbieta Kowalska ◽  
Sławomir Łapiński ◽  
Marcin Rajner ◽  
Krzysztof Bakuła
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Satellite System ◽  
Scientific Activity ◽  
3D Modelling ◽  
Future Research ◽  
Digital Elevation ◽  
The Mean ◽  
Elevation Model ◽  
Global Navigation Satellite

ABSTRACTThis paper presents survey measurements carried out during the 39th Polish Antarctic Expedition to the Henryk Arctowski Polish Antarctic Station in March 2015. The measurements were used to create a map on a 1:500 scale and for 3D modelling of the station buildings and vicinity. The paper also presents the geodetic control network established around the station. We discuss the issue of creating a digital elevation model for the station and its surroundings. The elevation models were generated using terrestrial laser scanning data integrated with Global Navigation Satellite System real time kinematic and tacheometric surveying. The accuracy of these models was estimated using height differences in relation to survey data. The mean height difference was 0.03 m and root mean square error was 0.05 m. Furthermore, an analysis of changes to the coastline was conducted using archival cartographic materials to assess the threat of Admiralty Bay to the station buildings. The results are important for continued scientific activity and safety at Arctowski Station, and may be useful for future research on King George Island.

scholarly journals Non-Tidal Mass Variations in the IGS Second Reprocessing Campaign: Interpretations and Noise Analysis from GRACE and Geophysical Models

2020 ◽  
Vol 12 (15) ◽  
pp. 2477
Author(s):  
Liansheng Deng ◽  
Hua Chen ◽  
Ailong Ma ◽  
Qusen Chen
Keyword(s):  
Noise Analysis ◽  
Satellite System ◽  
Global Scale ◽  
Loading Effects ◽  
The Mean ◽  
Tidal Loading ◽  
Global Navigation Satellite ◽  
Gravity Recovery ◽  
Noise Models ◽  
Vertical Deformations

Vertical deformations caused by non-tidal mass variations still remain in global navigation satellite system (GNSS) height time series, and can be computed from both Gravity Recovery and Climate Experiment (GRACE) and geophysical models. In this study, we provide a thorough evaluation of the relationships between these different techniques in the global scale by comparing non-tidal vertical deformations from IGS second reprocessing campaign (IG2), GRACE and Global Geophysical Fluid Center (GGFC) solutions, and investigate the noise properties of the GNSS corrected by GRACE solutions and GNSS corrected by GGFC solutions for global stations using optimal noise models. Our results demonstrate that the consistency between seasonal vertical deformations derived from GNSS, GRACE and GGFC is high. When correcting GNSS deformations with GRACE and GGFC solutions, 81% and 73% of the 186 stations have the weight root mean square (WRMS) reduction, respectively. The WRMS variations averaged over all stations are −12.3% and −5.6%, respectively for GNSS corrected by GRACE and GNSS corrected by GGFC solutions. The obvious difference occurs in the GNSS corrected by GGFC solutions WRMS increase, with the mean increase value up to 29%, mainly happening to stations located on islands or small peninsulas. In addition, noise properties of the GNSS corrected by GRACE solutions and GNSS corrected by GGFC solutions for global stations are investigated using optimal noise models. After correcting non-tidal loading effects, the solutions of GNSS corrected by GRACE solutions have the lowest noise level, and can occupy 5% of the noise behavior presenting in global stations, while the solutions of GNSS corrected by GGFC solutions can bring more than 5% of the noise into global stations, implying that GRACE correction solutions can present more favorable results when interpreting GNSS non-tidal loading deformations.

Sign in / Sign up

Export Citation Format

Share Document