New Methodology for Computing the Aircraft’s Position Based on the PPP Method in GPS and GLONASS Systems

In the field of air navigation, there is a constant pursuit for new navigation solutions for precise GNSS (Global Navigation Satellite System) positioning of aircraft. This study aims to present the results of research on the development of a new method for improving the performance of PPP (Precise Point Positioning) positioning in the GPS (Global Positioning System) and GLONASS (Globalnaja Nawigacionnaja Sputnikovaya Sistema) systems for air navigation. The research method is based on a linear combination of individual position solutions from the GPS and GLONASS systems. The paper shows a computational scheme based on the linear combination for geocentric XYZ coordinates of an aircraft. The algorithm of the new research method uses the weighted mean method to determine the resultant aircraft position. The research method was tested on GPS and GLONASS kinematic data from an airborne experiment carried out with a Seneca Piper PA34-200T aircraft at the Mielec airport. A dual-frequency dual-system GPS/GLONASS receiver was placed on-board the plane, which made it possible to record GNSS observations, which were then used to calculate the aircraft’s position in CSRS-PPP software. The calculated XYZ position coordinates from the CSRS-PPP software were then used in the weighted mean model’s developed optimization algorithm. The measurement weights are a function of the number of GPS and GLONASS satellites and the inverse of the mean error square. The obtained coordinates of aircraft from the research model were verified with the RTK-OTF solution. As a result of the research, the presented solution’s accuracy is better by 11–87% for the model with a weighting scheme as a function of the inverse of the mean error square. Moreover, using the XYZ position from the RTKLIB program, the research method’s accuracy increases from 45% to 82% for the model with a weighting scheme as a function of the inverse of the square of mean error. The developed method demonstrates high efficiency for improving the performance of GPS and GLONASS solutions for the PPP measurement technology in air navigation.

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Estimating ambiguity fixed satellite orbit, integer clock and daily bias products for GPS L1/L2, L1/L5 and Galileo E1/E5a, E1/E5b signals

Journal of Geodesy ◽

10.1007/s00190-021-01500-0 ◽

2021 ◽

Vol 95 (4) ◽

Author(s):

Bingbing Duan ◽

Urs Hugentobler ◽

Inga Selmke ◽

Ningbo Wang

Keyword(s):

Linear Combination ◽

Ambiguity Resolution ◽

Phase Measurement ◽

Satellite Orbit ◽

Satellite System ◽

Dual Frequency ◽

Carrier Phase Measurement ◽

Station Coordinates ◽

Wide Lane ◽

The Mean

AbstractAmbiguity resolution of a single receiver is becoming more and more popular for precise GNSS (Global Navigation Satellite System) applications. To serve such an approach, dedicated satellite orbit, clock and bias products are needed. However, we need to be sure whether products based on specific frequencies and signals can be used when processing measurements of other frequencies and signals. For instance, for Galileo E5a frequency, some receivers track only the pilot signal (C5Q) while some track only the pilot-data signal (C5X). We cannot compute the differences between C5Q and C5X directly since these two signals are not tracked concurrently by any common receiver. As code measurements contribute equally as phase in the Melbourne-Wuebbena (MelWub) linear combination it is important to investigate whether C5Q and C5X can be mixed in a network to compute a common satellite MelWub bias product. By forming two network clusters tracking Q and X signals, respectively, we confirm that GPS C5Q and C5X signals cannot be mixed together. Because the bias differences between GPS C5Q and C5X can be more than half of one wide-lane cycle. Whereas, mixing of C5Q and C5X signals for Galileo satellites is possible. The RMS of satellite MelWub bias differences between Q and X cluster is about 0.01 wide-lane cycles for both E1/E5a and E1/E5b frequencies. Furthermore, we develop procedures to compute satellite integer clock and narrow-lane bias products using individual dual-frequency types. Same as the finding from previous studies, GPS satellite clock differences between L1/L2 and L1/L5 estimates exist and show a periodical behavior, with a peak-to-peak amplitude of 0.7 ns after removing the daily mean difference of each satellite. For Galileo satellites, the maximum clock difference between E1/E5a and E1/E5b estimates after removing the mean value is 0.04 ns and the mean RMS of differences is 0.015 ns. This is at the same level as the noise of the carrier phase measurement in the ionosphere-free linear combination. Finally, we introduce all the estimated GPS and Galileo satellite products into PPP-AR (precise point positioning, ambiguity resolution) and Sentinel-3A satellite orbit determination. Ambiguity fixed solutions show clear improvement over float solutions. The repeatability of five ground-station coordinates show an improvement of more than 30% in the east direction when using both GPS and Galileo products. The Sentinel-3A satellite tracks only GPS L1/L2 measurements. The standard deviation (STD) of satellite laser ranging (SLR) residuals is reduced by about 10% when fixing ambiguity parameters to integer values.

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Evaluating the Accuracy of Determining Coordinates of a Corner of a Building Measured in the RTN GNSS Mode, Having Applied the Innovative Algorithm of Vector Translation

Reports on Geodesy and Geoinformatics ◽

10.1515/rgg-2017-0002 ◽

2017 ◽

Vol 103 (1) ◽

pp. 10-21

Author(s):

Robert Krzyżek

Keyword(s):

Real Time ◽

Satellite System ◽

Reference Points ◽

Mean Error ◽

Base Points ◽

Study Results ◽

Innovative Solution ◽

The Mean ◽

Global Navigation Satellite

Abstract The study evaluates the accuracy of determining coordinates of a corner of a building measured in the RTN GNSS mode (Real Time Network Global Navigation Satellite System) using the method of line-line intersection and having applied the algorithm of vector translation, developed by the author. The performed analysis of accuracy proved a high precision in determining the points subjected to studies. An important factor in the formation of a mean error regarding the position of the corner of a building, having used the algorithm of vector translation, is the assumption of correctness of the reference points, i.e. the so-called base points, determined in the RTN GNSS mode. In this case, the base points take the role of measurement control points. The mean error of the position of the corner of a building, taking into account the innovative solution, is at the level of several centimeters. The study results presented in the article allow to positively evaluate the algorithm of vector translation in terms of accuracy of determining the position of a corner of a building, measured in real time.

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The Transit System

Journal of Navigation ◽

10.1017/s0373463300035943 ◽

1962 ◽

Vol 15 (2) ◽

pp. 129-144 ◽

Cited By ~ 4

Author(s):

R. B. Kershner ◽

R. R. Newton

Keyword(s):

United States ◽

The United States ◽

Satellite System ◽

Transit System ◽

Mean Error ◽

Johns Hopkins University ◽

Navigation Error ◽

The Mean

The Transit navigational satellite system is expected to be in operational use during the second half of 1962, though not perhaps with its full quota of four satellites. The system, which will be of considerable significance to both air and surface navigation, is here described by its originators, Dr. Kershner and Dr. Newton, of Johns Hopkins University in the United States. Using a single of the two frequencies transmitted by the satellite, the mean navigation error will be about one mile, limited by refraction. Using both frequencies the mean error will be about ½ mile, limited by the accuracy of the satellite coordinates that will be transmitted. With elaborate equipment, it will be possible to navigate to about 0·1 mile, although the satellite coordinates that will be available to the ordinary user will not reflect this full accuracy. When all four satellites are in orbit, a fix will be available every 110 minutes, on the average, with occasional intervals of 220 minutes between fixes.

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UPAYA MENINGKATKAN HASIL BELAJAR IPA MELALUI PENGGUNAAN VIDEO PEMBELAJARAN BAGI SISWA KELAS IV DI SDN 187/IV KOTA JAMBI

Jurnal Dinamika Pendidikan ◽

10.33541/jdp.v8i2.119 ◽

2015 ◽

Vol 8 (2) ◽

pp. 93

Author(s):

Juniar Siregar

Keyword(s):

Action Research ◽

Research Method ◽

Research Report ◽

The Third ◽

The Media ◽

The Subject ◽

The Mean ◽

Classroom Action Research

This study presents a research report on improving students’ Learning results on IPA through Video. The objective was to find out whether students’ learning result improved when they are taught by using Video. It was conducted using classroom action research method. The subject of the study was the Grade IV students of SDN 187/IV Kota Jambi which is located on Jln. Adi Sucipto RT 05 Kecamatan Jambi Selatan, and the number of the students were 21 persons. The instruments used were test. In analyzing the data, the mean of the students’ score for the on fisrt sycle was 65,4 (42,85%) and the mean on cycle two was 68,5 (37,15%) and the mean of the third cycle was 81,4 (100%). Then it can be concluded that the use of video on learning IPA can improve the students’ learning result. It is suggested that teachers should use video as one of the media to improve students’ learning result on IPA.Keywords : IPA, students’ learning result, video

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IMPROVING STUDENTS’ WRITING ACHIEVEMENT IN THE REPORT TEXT THROUGH FILM

10.24114/reg.v2i4.841 ◽

2013 ◽

Vol 2 (4) ◽

Author(s):

Esra N.F. Hutahaean And Tjut Ernidawati

Keyword(s):

Action Research ◽

Research Method ◽

Writing Achievement ◽

The Third ◽

Total Percentage ◽

The Subject ◽

The Mean ◽

Report Text

This research concerns on improving students’ writing achievement in the report text through film. The objective was to find out the improvement of students’ writing achievement in writing the report text through film. This research was conducted by using action research method. The subject of the research was XI IPA grade students of SMA SWASWTA JOSUA Medan. The numbers of students were thirty one students. They were taught writing the report text through film. The instruments used were writing report text test, diary notes, interview sheets, questionnaire sheets and observation sheets. In analyzing data, the mean of students’ score for the first competency test was 43.1, for the second competency test was 64.8 and for the third competency test was 76.3 and the total percentage of improvement from the first competency test to the third competency test was 84.1%. The conclusion is that through watching film can improve the students’ writing achievement in the report text. It is suggested that teachers should apply watching film as one of media to improve students’ writing achievement in the report text.

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Measurements of the excess volume of benzene-methanol, benzene-acetonitrile and methanol-acetonitrile mixtures by a vibrating-tube densimeter

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19790295 ◽

1979 ◽

Vol 44 (2) ◽

pp. 295-306 ◽

Cited By ~ 20

Author(s):

Ivan Cibulka ◽

Vladimír Hynek ◽

Robert Holub ◽

Jiří Pick

Keyword(s):

Excess Volume ◽

Density Measurement ◽

Indirect Measurement ◽

Measuring System ◽

Mean Error ◽

Shaped Tube ◽

Underlying Principle ◽

The Mean ◽

Vibrating Tube Densimeter

A digital vibrating-tube densimeter was constructed for measuring the density of liquids at several temperatures. The underlying principle of the apparatus is the measurement of the period of eigen-vibrations of a V-shaped tube; the second power of the period of the vibrations is proportional to the density of the liquid in the tube. The temperature of the measuring system is controlled by an electronic regulator. The mean error in the density measurement is approximately ±1 . 10-5 g cm-3 at 25 °C and ±2 . 10-5 g cm-3 at 40 °C. The apparatus was used for an indirect measurement of the excess volume, tested with the benzene-cyclohexane system and further used for determining the excess volume of the benzene-methanol, benzene-acetonitrile and methanol-acetonitrile systems at 25 and 40 °C.

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Estimation of fractional cycle bias for GPS/BDS-2/Galileo based on international GNSS monitoring and assessment system observations using the uncombined PPP model

Satellite Navigation ◽

10.1186/s43020-021-00039-x ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Jin Wang ◽

Qin Zhang ◽

Guanwen Huang

Keyword(s):

Estimation Method ◽

Satellite Orbit ◽

Satellite System ◽

Assessment System ◽

Navigation Satellite ◽

Dual Frequency ◽

Fractional Cycle Bias ◽

The Stability ◽

High Consistency ◽

Global Navigation Satellite

AbstractThe Fractional Cycle Bias (FCB) product is crucial for the Ambiguity Resolution (AR) in Precise Point Positioning (PPP). Different from the traditional method using the ionospheric-free ambiguity which is formed by the Wide Lane (WL) and Narrow Lane (NL) combinations, the uncombined PPP model is flexible and effective to generate the FCB products. This study presents the FCB estimation method based on the multi-Global Navigation Satellite System (GNSS) precise satellite orbit and clock corrections from the international GNSS Monitoring and Assessment System (iGMAS) observations using the uncombined PPP model. The dual-frequency raw ambiguities are combined by the integer coefficients (4,− 3) and (1,− 1) to directly estimate the FCBs. The details of FCB estimation are described with the Global Positioning System (GPS), BeiDou-2 Navigation Satellite System (BDS-2) and Galileo Navigation Satellite System (Galileo). For the estimated FCBs, the Root Mean Squares (RMSs) of the posterior residuals are smaller than 0.1 cycles, which indicates a high consistency for the float ambiguities. The stability of the WL FCBs series is better than 0.02 cycles for the three GNSS systems, while the STandard Deviation (STD) of the NL FCBs for BDS-2 is larger than 0.139 cycles. The combined FCBs have better stability than the raw series. With the multi-GNSS FCB products, the PPP AR for GPS/BDS-2/Galileo is demonstrated using the raw observations. For hourly static positioning results, the performance of the PPP AR with the three-system observations is improved by 42.6%, but only 13.1% for kinematic positioning results. The results indicate that precise and reliable positioning can be achieved with the PPP AR of GPS/BDS-2/Galileo, supported by multi-GNSS satellite orbit, clock, and FCB products based on iGMAS.

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

Water ◽

10.3390/w13060812 ◽

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.

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Conditioning and PPP processing of smartphone GNSS measurements in realistic environments

Satellite Navigation ◽

10.1186/s43020-021-00042-2 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Ganga Shinghal ◽

Sunil Bisnath

Keyword(s):

Single Point ◽

A Priori ◽

Density Ratio ◽

Satellite System ◽

Quality Parameters ◽

Urban Environments ◽

Dual Frequency ◽

Missing Measurements ◽

Data Gaps ◽

Point Positioning

AbstractSmartphones typically compute position using duty-cycled Global Navigation Satellite System (GNSS) L1 code measurements and Single Point Positioning (SPP) processing with the aid of cellular and other measurements. This internal positioning solution has an accuracy of several tens to hundreds of meters in realistic environments (handheld, vehicle dashboard, suburban, urban forested, etc.). With the advent of multi-constellation, dual-frequency GNSS chips in smartphones, along with the ability to extract raw code and carrier-phase measurements, it is possible to use Precise Point Positioning (PPP) to improve positioning without any additional equipment. This research analyses GNSS measurement quality parameters from a Xiaomi MI 8 dual-frequency smartphone in varied, realistic environments. In such environments, the system suffers from frequent phase loss-of-lock leading to data gaps. The smartphone measurements have low and irregular carrier-to-noise (C/N0) density ratio and high multipath, which leads to poor or no positioning solution. These problems are addressed by implementing a prediction technique for data gaps and a C/N0-based stochastic model for assigning realistic a priori weights to the observables in the PPP processing engine. Using these conditioning techniques, there is a 64% decrease in the horizontal positioning Root Mean Square (RMS) error and 100% positioning solution availability in sub-urban environments tested. The horizontal and 3D RMS were 20 cm and 30 cm respectively in a static open-sky environment and the horizontal RMS for the realistic kinematic scenario was 7 m with the phone on the dashboard of the car, using the SwiftNav Piksi Real-Time Kinematic (RTK) solution as reference. The PPP solution, computed using the YorkU PPP engine, also had a 5–10% percentage point more availability than the RTK solution, computed using RTKLIB software, since missing measurements in the logged file cause epoch rejection and a non-continuous solution, a problem which is solved by prediction for the PPP solution. The internal unaided positioning solution of the phone obtained from the logged NMEA (The National Marine Electronics Association) file was computed using point positioning with the aid of measurements from internal sensors. The PPP solution was 80% more accurate than the internal solution which had periodic drifts due to non-continuous computation of solution.

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Assessment of necessity of neuronavigation in localization of calvarial extra-axial lesions in the setting of limited resources

Chinese Neurosurgical Journal ◽

10.1186/s41016-021-00253-1 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Hussein Soffar ◽

Mohamed F. Alsawy

Keyword(s):

Conventional Method ◽

Linear Measurement ◽

Limited Resources ◽

Linear Measurements ◽

Surgical Interventions ◽

Localization Method ◽

Mean Error ◽

Significant Difference ◽

The Mean ◽

Mean Time

Abstract Background Neuronavigation is a very beneficial tool in modern neurosurgical practice. However, the neuronavigation is not available in most of the hospitals in our country raising the question about its importance in localizing the calvarial extra-axial lesions and to what extent it is safe to operate without it. Methods We studied twenty patients with calvarial extra-axial lesions who underwent surgical interventions. All lesions were preoperatively located with both neuronavigation and the usual linear measurements. Both methods were compared regarding the time consumed to localize the tumor and the accuracy of each method to anticipate the actual center of the tumor. Results The mean error of distance between the planned center of the tumor and the actual was 6.50 ± 1.762 mm in conventional method, whereas the error was 3.85 ± 1.309 mm in IGS method. Much more time was consumed during the neuronavigation method including booting, registration, and positioning. A statistically significant difference was found between the mean time passed in the conventional method and IGS method (2.05 ± 0.826, 24.90 ± 1.334, respectively), P-value < 0.001. Conclusion In the setting of limited resources, the linear measurement localization method seems to have an accepted accuracy in the localization of calvarial extra-axial lesions and it saves more time than neuronavigation method.

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