scholarly journals Time synchronization requirement of global navigation satellite system augmentation system based on pseudolite

2019 ◽  
Vol 52 (3-4) ◽  
pp. 303-313 ◽  
Author(s):  
Chao Ma ◽  
Jun Yang ◽  
Jianyun Chen ◽  
Yinyin Tang
Keyword(s):  
Time Synchronization ◽  
Vertical Direction ◽  
Civil Aviation ◽  
Engineering Practice ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Dilution Of Precision ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
The Impact

Global navigation satellite systems are widely used across the world because of their continuous/all-weather, global coverage, and high precision positioning. But, three-dimensional positioning accuracy, especially in the vertical direction, remains insufficient because of the geometric distribution of satellites. This is especially true for air-borne objects such as unmanned aerial vehicles, civil aviation devices, and missiles. To solve this problem, we adopt a satellite-ground joint positioning system based on a pseudo-satellite (pseudolite). The introduction of ground pseudolites can significantly reduce the vertical dilution of precision and improve positioning accuracy. This method has been proposed in the 1980s. However, we have to ask a question, as long as we add a pseudolite, can the positioning accuracy be improved? The answer is no. Pseudolites can cause time synchronization problems with satellites, and the resulting timing errors of the pseudolite are converted into pseudorange errors, reducing accuracy. Here, we seek to evaluate the impact of the reduced vertical dilution of precision and the increased range errors associated with the introduction of a pseudolite on the ground. We derive a mathematical formula to explain this relationship. We conclude that when the satellite range error and the change in the position dilution of precision associated with a pseudolite are known, we can calculate an approximate limit for the pseudolite timing accuracy to ensure that the use of the pseudolite improves the positioning accuracy. This work should be of great value in guiding engineering practice.

Institutional Aspects of a Global Navigation Satellite System

2000 ◽  
Vol 53 (2) ◽  
pp. 261-271 ◽  
Author(s):  
D. Brocklebank ◽  
J. Spiller ◽  
T. Tapsell
Keyword(s):  
European Space Agency ◽  
Private Investment ◽  
Global Navigation Satellite Systems ◽  
European Symposium ◽  
Economic Regulation ◽  
Navigation Satellite ◽  
The European Union ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
The Impact

This, and the following three papers, where first presented at GNSS 99, the Second European Symposium on Global Navigation Satellite Systems held in Genoa, Italy from 5th to 8th October 1999.Galileo is being developed as the European contribution to the next generation of navigation satellites to replace GNSS1. Sponsored by the European Union, Galileo will be a civil, internationally controlled and operated system that will secure the long-term availability of satellite-based navigation services for multi-modal purposes throughout the European region and beyond. Galileo will be designed to support a wide variety of applications. These include professional navigation, position reference, safety, emergency, tracking, sport/leisure and governmental. Such services may be open to all, for safety-of-life applications, or for commercial users. In the case of safety and commercial applications in particular, it is imperative that the appropriate institutional control and regulatory framework is in place for purposes of safety and economic regulation. To ensure that the various parties understand their obligations and liabilities, clear legal instruments must be put in place to support the organisational framework. It is planned to attract private investment to fund elements of system development and operation through Private/Public Partnership arrangements. At present there is no institutional, regulatory or legal framework that will enable the early impetus to Galileo development to be maintained. This presents a challenge that Europe must address without delay. It has been the subject of several European Commission studies in the past twelve months. In a complementary activity under contract to the European Space Agency (ESA), a European industry consortium comprising Alcatel, Alenia, DASA and Matra Marconi Space was tasked to complete the preliminary design of the space and ground segments by the Autumn of 1999. One task of this study, led by Matra Marconi Space, relates to a study of the impact of institutional, regulatory and legal issues on the organisation and development of Galileo. This paper describes the studies undertaken into these issues within the overall Galileo development programme.

scholarly journals Multi-GNSS Combined Precise Point Positioning Using Additional Observations with Opposite Weight for Real-Time Quality Control

2019 ◽  
Vol 11 (3) ◽  
pp. 311 ◽  
Author(s):  
Wenju Fu ◽  
Guanwen Huang ◽  
Yuanxi Zhang ◽  
Qin Zhang ◽  
Bobin Cui ◽  
...  
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite

The emergence of multiple global navigation satellite systems (multi-GNSS), including global positioning system (GPS), global navigation satellite system (GLONASS), Beidou navigation satellite system (BDS), and Galileo, brings not only great opportunities for real-time precise point positioning (PPP), but also challenges in quality control because of inevitable data anomalies. This research aims at achieving the real-time quality control of the multi-GNSS combined PPP using additional observations with opposite weight. A robust multiple-system combined PPP estimation is developed to simultaneously process observations from all the four GNSS systems as well as single, dual, or triple systems. The experiment indicates that the proposed quality control can effectively eliminate the influence of outliers on the single GPS and the multiple-system combined PPP. The analysis on the positioning accuracy and the convergence time of the proposed robust PPP is conducted based on one week’s data from 32 globally distributed stations. The positioning root mean square (RMS) error of the quad-system combined PPP is 1.2 cm, 1.0 cm, and 3.0 cm in the east, north, and upward components, respectively, with the improvements of 62.5%, 63.0%, and 55.2% compared to those of single GPS. The average convergence time of the quad-system combined PPP in the horizontal and vertical components is 12.8 min and 12.2 min, respectively, while it is 26.5 min and 23.7 min when only using single-GPS PPP. The positioning performance of the GPS, GLONASS, and BDS (GRC) combination and the GPS, GLONASS, and Galileo (GRE) combination is comparable to the GPS, GLONASS, BDS and Galileo (GRCE) combination and it is better than that of the GPS, BDS, and Galileo (GCE) combination. Compared to GPS, the improvements of the positioning accuracy of the GPS and GLONASS (GR) combination, the GPS and Galileo (GE) combination, the GPS and BDS (GC) combination in the east component are 53.1%, 43.8%, and 40.6%, respectively, while they are 55.6%, 48.1%, and 40.7% in the north component, and 47.8%, 40.3%, and 34.3% in the upward component.

scholarly journals Testing the Positioning Accuracy of GNSS Solutions during the Tramway Track Mobile Satellite Measurements in Diverse Urban Signal Reception Conditions

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3646 ◽  
Author(s):  
Mariusz Specht ◽  
Cezary Specht ◽  
Andrzej Wilk ◽  
Władysław Koc ◽  
Leszek Smolarek ◽  
...  
Keyword(s):  
Global Navigation Satellite System ◽  
Geodetic Network ◽  
Satellite System ◽  
Railway Vehicle ◽  
Navigation Satellite ◽  
Design Work ◽  
System Solution ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
The Impact

Mobile Global Navigation Satellite System (GNSS) measurements carried out on the railway consist of using satellite navigation systems to determine the track geometry of a moving railway vehicle on a given route. Their purposes include diagnostics, stocktaking, and design work in railways. The greatest advantage of this method is the ability to perform measurements in a unified and coherent spatial reference system, which effectively enables the combining of design and construction works, as well as their implementation by engineering teams of diverse specialties. In the article, we attempted to assess the impact of using three types of work mode for a GNSS geodetic network [Global Positioning System (GPS), GPS/Global Navigation Satellite System (GLONASS) and GPS/GLONASS/Galileo] on positioning availability at three accuracy levels: 1 cm, 3 cm and 10 cm. This paper presents a mathematical model that enables the calculation of positioning availability at these levels. This model was also applied to the results of the measurement campaign performed by five GNSS geodetic receivers, made by a leading company in the field. Measurements with simultaneous position recording and accuracy assessment were taken separately on the same route for three types of receiver settings: GPS, GPS/GLONASS and GPS/GLONASS/Galileo in an urban area typical of a medium-sized city. The study has shown that applying a two-system solution (GPS/GLONASS) considerably increases the availability of high-precision coordinates compared to a single-system solution (GPS), whereas the measurements with three systems (GPS/GLONASS/Galileo) negligibly increase the availability compared to a two-system solution (GPS/GLONASS).

Lower Bounds on DOP

2017 ◽  
Vol 70 (5) ◽  
pp. 1041-1061 ◽  
Author(s):  
Peter F. Swaszek ◽  
Richard J. Hartnett ◽  
Kelly C. Seals
Keyword(s):  
Lower Bounds ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Satellite Constellations ◽  
Dilution Of Precision ◽  
Gnss Positioning ◽  
Satellite Selection ◽  
Global Navigation ◽  
Global Navigation Satellite

Code phase Global Navigation Satellite System (GNSS) positioning performance is often described by the Geometric or Position Dilution of Precision (GDOP or PDOP), functions of the number of satellites employed in the solution and their geometry. This paper develops lower bounds to both metrics solely as functions of the number of satellites, effectively removing the added complexity caused by their locations in the sky, to allow users to assess how well their receivers are performing with respect to the best possible performance. Such bounds will be useful as receivers sub-select from the plethora of satellites available with multiple GNSS constellations. The bounds are initially developed for one constellation assuming that the satellites are at or above the horizon. Satellite constellations that essentially achieve the bounds are discussed, again with value toward the problem of satellite selection. The bounds are then extended to a non-zero mask angle and to multiple constellations.

scholarly journals Testing of Software for the Planning of a Linear Object GNSS Measurement Campaign under Simulated Conditions

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7896
Author(s):  
Sławomir Figiel ◽  
Cezary Specht ◽  
Marek Moszyński ◽  
Andrzej Stateczny ◽  
Mariusz Specht
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Dilution Of Precision ◽  
Measurement Campaign ◽  
Average Value ◽  
Linear Object ◽  
Global Navigation ◽  
On The Road ◽  
Global Navigation Satellite

The precision of a linear object measurement using satellite techniques is determined by the number and the relative position of the visible satellites by the receiver. The status of the visible constellation is described by the Dilution Of Precision (DOP). The obtained geometric coefficient values are dependent on many variables. When determining these values, field obstacles at the receiver location and satellite positions changing with time must be taken into account. Carrying out a series of surveys as part of a linear object Global Navigation Satellite System (GNSS) measurement campaign requires the optimisation problem to be solved. The manner of the inspection vehicle’s movement should be determined in such a way that the surveys are taken only within the pre-defined time frames and that the geometric coefficient values obtained at subsequent points of the route are as low as possible. The purpose of this article is to develop a software for the planning of a linear object GNSS measurement campaign to implemented in motion and taking into account the terrain model and its coverage. Additionally, it was determined how much the developed program improves DOP values on the planned route under simulated conditions. This software has no equivalent elsewhere in the world, as the current solutions for the planning of a GNSS measurement campaign, e.g., Trimble GNSS Planning, GNSS Mission Planning, or GPS Navigation Toolbox, allow the satellite constellation geometry to be analysed exclusively for specific coordinates and at a specific time. Analysis of the obtained simulation test results indicates that the campaign implementation in accordance with the pre-determined schedule significantly improves the quality of the recorded GNSS data. This is particularly noticeable when determining the position using the Global Positioning System (GPS) and GLObal NAvigation Satellite System (GLONASS) satellite constellations at the same time. During the tests conducted on the road along a three-kilometre-long route (tram loop) in Gdańsk Brzeźno, the average value of the obtained Position Dilution Of Precision (PDOP) decreased by 22.17% thanks to using the software to plan a linear object GNSS measurement campaign. The largest drop in the geometric coefficient values was noted for an area characterised by a very large number of field obstacles (trees with crowns and high buildings). Under these conditions, the PDOP value decreased by approx. 25%. In areas characterised by a small number of field obstacles (single trees in the vicinity of the track, clusters of trees and buildings located along the track), the changes in the PDOP were slightly smaller and amounted to several percent.

Geolocal – A New System for Geo-Referencing: Analysis of Base Distribution

2020 ◽  
pp. 1-13
Author(s):  
Eduardo P. Macho ◽  
Sergio V.D. Pamboukian ◽  
Emília Correia
Keyword(s):  
Time Delay ◽  
Navigation System ◽  
Measurement Errors ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Dilution Of Precision ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
New System

Geolocal is a new navigation system conceived and patented in Brazil, whose purpose is to be independent of other global navigation satellite systems (GNSS). It has an ‘inverted-GNSS’ configuration with at least four bases on the ground at known geodesic position coordinates and a repeater in space. Simulations were performed to determine the precision of Geolocal using different quantities and distributions of bases. They showed that this precision is enhanced when the quantity of bases increases, as long as the elevation angles of the new bases included are higher than the average and when the bases are evenly distributed around the repeater, but mainly when the time delay at the repeater is known in advance and when the measurement errors that generate uncertainties are reduced. The position dilution of precision (PDOP) was also calculated, confirming that precision is enhanced by the quantity of bases and by their distribution.

scholarly journals The Effect of Different Global Navigation Satellite System Methods on Positioning Accuracy in Elite Alpine Skiing

Sensors ◽  
2014 ◽  
Vol 14 (10) ◽  
pp. 18433-18453 ◽  
Author(s):  
Matthias Gilgien ◽  
Jörg Spörri ◽  
Philippe Limpach ◽  
Alain Geiger ◽  
Erich Müller
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Alpine Skiing ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Global Navigation Satellite

scholarly journals A Quad-Constellation GNSS Navigation Algorithm with Colored Noise Mitigation

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5563
Author(s):  
Xianqiang Cui ◽  
Tianhang Gao ◽  
Changsheng Cai
Keyword(s):  
Global Navigation Satellite System ◽  
Colored Noise ◽  
Satellite System ◽  
Navigation Satellite ◽  
Noise Mitigation ◽  
Positioning Accuracy ◽  
Navigation Algorithm ◽  
Satellite Visibility ◽  
Global Navigation ◽  
Global Navigation Satellite

The existence of colored noise in kinematic positioning will greatly degrade the accuracy of position solutions. This paper proposes a Kalman filter-based quad-constellation global navigation satellite system (GNSS) navigation algorithm with colored noise mitigation. In this algorithm, the observation colored noise and state colored noise models are established by utilizing their residuals in the past epochs, and then the colored noise is predicted using the models for mitigation in the current epoch in the integrated Global Positioning System (GPS)/GLObal NAvigation Satellite System (GLONASS)/BeiDou Navigation Satellite System (BDS)/Galileo navigation. Kinematic single point positioning (SPP) experiments under different satellite visibility conditions and road patterns are conducted to evaluate the effect of colored noise on the positioning accuracy for the quad-constellation combined navigation. Experiment results show that the colored noise model can fit the colored noise more effectively in the case of good satellite visibility. As a result, the positioning accuracy improvement is more significant after handling the colored noise. The three-dimensional positioning accuracy can be improved by 25.1%. Different satellite elevation cut-off angles of 10º, 20º and 30º are set to simulate different satellite visibility situations. Results indicate that the colored noise is decreased with the increment of the elevation cut-off angle. Consequently, the improvement of the SPP accuracy after handling the colored noise is gradually reduced from 27.3% to 16.6%. In the cases of straight and curved roads, the quad-constellation GNSS-SPP accuracy can be improved by 22.1% and 25.7% after taking the colored noise into account. The colored noise can be well-modeled and mitigated in both the straight and curved road conditions.

Sign in / Sign up

Export Citation Format

Share Document