scholarly journals Performance of GPS Positioning in the Presence of Irregularities in the Auroral and Polar Ionospheres during EISCAT UHF/ESR Measurements

2021 ◽  
Vol 13 (23) ◽  
pp. 4798
Author(s):  
Habila Mormi John ◽  
Biagio Forte ◽  
Ivan Astin ◽  
Tom Allbrook ◽  
Alex Arnold ◽  
...  
Keyword(s):  
Global Navigation Satellite Systems ◽  
Positioning Error ◽  
Satellite Systems ◽  
Gps Positioning ◽  
Transient Nature ◽  
Radio Signals ◽  
E Region ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Residual Errors

Irregularities in the spatial distribution of ionospheric electron density introduce temporal fluctuations in the intensity and phase of radio signals received from Global Navigation Satellite Systems (GNSS). The impact of phase fluctuations originating from irregularities in the auroral and polar ionospheres on GPS positioning was investigated on three days in March 2018 in the presence of quiet-to-moderately disturbed magnetic conditions by combining measurements from GPS and EISCAT UHF/ESR incoherent scatter radars. Two different positioning solutions were analysed: broadcast kinematic (BK) and precise static (PS). The results show that the propagation through irregularities induced residual errors on the observables leading to an increase in the positioning error, in its variability, and in the occurrence of gaps. An important aspect emerging from this study is that the variability of the 3-D positioning error was reduced, and the presence of gaps disappeared when the positioning solutions were evaluated at a 1 s rate rather than at a 30 s rate. This is due to the transient nature of residual errors that are more significant over 30 s time intervals in the presence of irregularities with scale size between few kilometres in the E region to few tens of kilometres in the F region.

How to make a multi-billion dollar thermometer

2021 ◽  
Vol 57 (2) ◽  
pp. 025003
Author(s):  
William H Baird
Keyword(s):  
Positional Information ◽  
The United States ◽  
Global Navigation Satellite Systems ◽  
Physics Students ◽  
Satellite Systems ◽  
Global Positioning ◽  
Field Programmable ◽  
Radio Signals ◽  
Global Navigation Satellite ◽  
Precise Time

Abstract The United States’ Global Positioning System (GPS), and similar geolocation systems such as Galileo, GLONASS, and Beidou are used by people all over the globe. Modern receivers of these global navigation satellite systems can track multiple satellites from different constellations. Casual, non-technical users are probably aware that the positional information provided is typically accurate to within a few meters. We could expect physics students to infer that, because these systems rely on the travel time of radio signals, this implies time measurement accuracy on the scale of tens of nanoseconds. This feature has led to GPS-enabled Internet time servers providing stratum 1 accuracy for under $1000. In this paper, we will show that we can couple a GPS unit to a field programmable gate array (FPGA) to determine the temperature in a room. The more serious application of this GPS-FPGA pairing is to provide precise time-stamping of events, thereby synchronizing data collection between stations across a room or across the globe.

Global Navigation Satellite Systems

2011 ◽  
pp. 348-352 ◽  
Author(s):  
Phillip Olla
Keyword(s):  
Global Navigation Satellite Systems ◽  
Global Network ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Mobile Phone Technology ◽  
Sensing Applications ◽  
Radio Signals ◽  
High Resolution Images ◽  
Global Navigation ◽  
Global Navigation Satellite

There is a need to determine precise ground locations for use in a variety of innovative and emerging applications such as earth observation, mobile-phone technology, and rescue applications. Location information is pertinent to a large number of remote sensing applications, some of which support strategic tasks such as disaster management, earth monitoring, protecting the environment, management of natural resources, and food production. With the availability of high-resolution images, some applications will require a location precision down to 1 m (Kline, 2004). The global navigation satellite systems (GNSSs) provide signals that can serve this purpose; these signals can be incorporated into a large range of innovative applications with immense benefits for the users (Hollansworth, 1999). Satellite navigation is achieved by using a global network of satellites that transmit radio signals from approximately 11,000 miles in high earth orbit. The technology is accurate enough to pinpoint locations anywhere in the world, 24 hours a day. Positions are provided in latitude, longitude, and altitude. This article provides an overview of the GNSSs in operation along with their uses.

scholarly journals On the Impact of Channel Cross-Correlations in High-Sensitivity Receivers for Galileo E1 OS and GPS L1C Signals

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Davide Margaria ◽  
Beatrice Motella ◽  
Fabio Dovis
Keyword(s):  
Cross Correlation ◽  
High Sensitivity ◽  
Global Navigation Satellite Systems ◽  
Integration Time ◽  
Noise Component ◽  
Satellite Systems ◽  
Coherent Integration ◽  
Global Navigation Satellite ◽  
Correlation Properties ◽  
The Impact

One of the most promising features of the modernized global navigation satellite systems signals is the presence of pilot channels that, being data-transition free, allow for increasing the coherent integration time of the receivers. Generally speaking, the increased integration time allows to better average the thermal noise component, thus improving the postcorrelation SNR of the receiver in the acquisition phase. On the other hand, for a standalone receiver which is not aided or assisted, the acquisition architecture requires that only the pilot channel is processed, at least during the first steps of the procedure. The aim of this paper is to present a detailed investigation on the impact of the code cross-correlation properties in the reception of Galileo E1 Open Service and GPS L1C civil signals. Analytical and simulation results demonstrate that the S-curve of the code synchronization loop can be affected by a bias around the lock point. This effect depends on the code cross-correlation properties and on the receiver setup. Furthermore, in these cases, the sensitivity of the receiver to other error sources might increase, and the paper shows how in presence of an interfering signal the pseudorange bias can be magnified and lead to relevant performance degradation.

scholarly journals CODE IGS reference products including Galileo

2020 ◽  
Author(s):  
Lars Prange ◽  
Arturo Villiger ◽  
Stefan Schaer ◽  
Rolf Dach ◽  
Dmitry Sidorov ◽  
...  
Keyword(s):  
Rapid Analysis ◽  
Global Navigation Satellite Systems ◽  
Processing Strategy ◽  
International Gnss Service ◽  
Satellite Systems ◽  
The World ◽  
Product Generation ◽  
Clock Correction ◽  
Global Navigation Satellite ◽  
The Impact

<p>The International GNSS service (IGS) has been providing precise reference products for the Global Navigation Satellite Systems (GNSS) GPS and (starting later) GLONASS since more than 25 years. These orbit, clock correction, coordinate reference frame, troposphere, ionosphere, and bias products are freely distributed and widely used by scientific, administrative, and commercial users from all over the world. The IGS facilities needed for data collection, product generation, product combination, as well as data and product dissemination, are well established. The Center for Orbit Determination in Europe (CODE) is one of the Analysis Centers (AC) contributing to the IGS from the beginning. It generates IGS products using the Bernese GNSS Software.</p><p> </p><p>In the last decade new GNSS (European Galileo and Chinese BeiDou) and regional complementary systems to GPS (Japanese QZSS and Indian IRNSS/NAVIC) were deployed. The existing GNSS are constantly modernized, offering - among others - more stable satellite clocks and new signals. The exploitation of the new data and their integration into the existing IGS infrastructure was the goal of the Multi-GNSS EXtension (MGEX) when it was initiated in 2012. CODE has been participating in the MGEX with its own orbit and clock solution from the beginning. Since 2014 CODE’s MGEX (COM) contribution considers five GNSS, namely GPS, GLONASS, Galileo, BeiDou2 (BDS2), and QZSS. We provide an overview of the latest developments of the COM solution with respect to processing strategy, orbit modelling, attitude modelling, antenna calibrations, handling of code and phase biases, and ambiguity resolution. The impact of these changes on the COM products will be discussed.</p><p> </p><p>Recent assessment showed that especially the Galileo analysis within the MGEX has reached a state of maturity, which is almost comparable to GPS and GLONASS. Based on this finding the IGS decided to consider Galileo in its third reprocessing campaign, which will contribute to the next ITRF. Recognizing the demands expressed by the GNSS community, CODE decided in 2019 to go a step further and consider Galileo also in its IGS RAPID and ULTRA-RAPID reference products. We summarize our experiences from the first months of triple-system (ULTRA)-RAPID analysis including GPS, GLONASS, and Galileo. Finally we provide an outlook of CODE’s IGS analysis with the focus on the new GNSS.</p>

scholarly journals Space weather: risk factors for Global Navigation Satellite Systems

2021 ◽  
Vol 7 (2) ◽  
pp. 28-47
Author(s):  
Vladislav Demyanov ◽  
Yury Yasyukevich
Keyword(s):  
Space Weather ◽  
Solar Radio ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Radio Navigation ◽  
Weather Events ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Extreme Space Weather Events

Extreme space weather events affect the stability and quality of the global navigation satellite systems (GNSS) of the second generation (GPS, GLONASS, Galileo, BeiDou/Compass) and GNSS augmentation. We review the theory about mechanisms behind the impact of geomagnetic storms, ionospheric irregularities, and powerful solar radio bursts on the GNSS user segment. We also summarize experimental observations of the space weather effects on GNSS performance in 2000–2020 to confirm the theory. We analyze the probability of failures in measurements of radio navigation parameters, decrease in positioning accuracy of GNSS users in dual-frequency mode and differential navigation mode (RTK), and in precise point positioning (PPP). Additionally, the review includes data on the occurrence of dangerous and extreme space weather phenomena and the possibility for predicting their im- pact on the GNSS user segment. The main conclusions of the review are as follows: 1) the positioning error in GNSS users may increase up to 10 times in various modes during extreme space weather events, as compared to the background level; 2) GNSS space and ground segments have been significantly modernized over the past decade, thus allowing a substantial in- crease in noise resistance of GNSS under powerful solar radio burst impacts; 3) there is a great possibility for increasing the tracking stability and accuracy of radio navigation parameters by introducing algorithms for adaptive lock loop tuning, taking into account the influence of space weather events; 4) at present, the urgent scientific and technical problem of modernizing GNSS by improving the scientific methodology, hardware and software for monitoring the system integrity and monitoring the availability of required navigation parameters, taking into account the impact of extreme space weather events, is still unresolved.

scholarly journals Research on the Heading Calibration for Foot-Mounted Inertial Pedestrian-Positioning System Based on Accelerometer Attitude

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1405
Author(s):  
Qiuying Wang ◽  
Kaiyue Liu ◽  
Zhiguo Sun ◽  
Muchun Cai ◽  
Ming Cheng
Keyword(s):  
Stance Phase ◽  
Correction Method ◽  
Global Navigation Satellite Systems ◽  
Positioning Error ◽  
Misalignment Angle ◽  
Continuous Increase ◽  
Satellite Systems ◽  
Error Correction Method ◽  
Global Navigation Satellite ◽  
The Relationship

Foot-mounted inertial pedestrian positioning (FIPP) plays an important role for facilitating pedestrian activities. It is suitable for indoor environment applications where global navigation satellite systems are unavailable such as during firefighting and military actions. However, the positioning error of FIPP can increase rapidly due to the measurement noise of the sensors. Zero Velocity Update (ZUPT) is an error correction method proposed to solve this accumulative error. However, the heading misalignment angle, which results in a continuous increase in the positioning error, cannot be estimated by ZUPT. In order to solve this problem, the improved ZUPT based on the Improved Attitude Algorithm (IAA) according to accelerometer measurements is proposed in this paper. When a pedestrian is in the stance phase, the horizontal attitude is estimated by using accelerometer measurements. According to the relationship between the heading misalignment angle and horizontal attitude, the heading misalignment angle is obtained by a series of mathematical derivations. By taking the velocity error and the attitude misalignment angle as observations, the heading misalignment angle and positioning error can be estimated and compensated for through the Kalman filter. Finally, we use MTI-G710 sensor manufactured by XSENS for the actual test and the experiment results show that the proposed method is effectively correct.

Critical Issues in Global Navigation Satellite Systems

2011 ◽  
pp. 151-157
Author(s):  
Ina Freeman ◽  
Jonathan M. Auld
Keyword(s):  
Atomic Clock ◽  
Global Navigation Satellite Systems ◽  
Time Interval ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Critical Issues ◽  
Radio Signals ◽  
Global Navigation ◽  
Defense Research ◽  
Global Navigation Satellite

Global Navigation Satellite Systems (GNSS) is a concept that relays accurate information of a position or location anywhere on the globe using a minimum of four satellites, a control station, and a user receiver. GNSS owes its origins to Rabi’s work in the early 1940s with the concept of an atomic clock (Nobel Museum, http://www.nobel.se/physics/laureates/1944/rabi-bio.html). In October 1940, the National Defense Research Council in the U.S. recommended implementing a new navigation system that combined radio signals with this new technology of time interval measurements. From this, MIT developed Long Range Radio Aid to Navigation (LORAN), which was refined by scientists at John Hopkins University and utilized during World War II through the late 1950s.

The Potential Impact of GNSS/INS Integration on Maritime Navigation

2008 ◽  
Vol 61 (2) ◽  
pp. 221-237 ◽  
Author(s):  
Terry Moore ◽  
Chris Hill ◽  
Andy Norris ◽  
Chris Hide ◽  
David Park ◽  
...  
Keyword(s):  
Field Trials ◽  
Global Navigation Satellite Systems ◽  
Navigation Systems ◽  
Inertial Navigation Systems ◽  
Satellite Systems ◽  
Time Period ◽  
Maritime Navigation ◽  
The Uk ◽  
Global Navigation Satellite ◽  
The Impact

A version of this paper was presented at ENC-GNSS 2007, Geneva. Its reproduction was kindly authorised by the ENC-GNSS 07 Paper Selection Committee.The General Lighthouse Authorities of the UK & Ireland commissioned an assessment of the impact that the integration of Global Navigation Satellite Systems (GNSS) with Inertial Navigation Systems (INS) would have on the aids to navigation (AtoN) services currently provided, and those to be provided in the future. There is concern about the vulnerability of GNSS, and the provision of complementary and backup systems is seen to be of great importance. The integration of INS could provide an independent and self-contained navigation system, for a limited time period, invulnerable to external intentional or unintentional interference, or the influences of changes in national policies. The study included an analysis of the potential use of GNSS-INS in three of the four phases of a vessel's voyage: coastal, port approach and docking. The project consisted of a technology assessment, looking at the different inertial technologies that might be suitable for each phase. This was followed by a technology proving stage, evaluating suitable equipment using simulation and field trials to prove that the claimed performance could be achieved in practice. The final stage of the project was to assess the effects of the availability of such systems on existing and planned aids to navigation services.

Earth Orientation Parameter Estimation by Integrating VLBI and GNSS on the Observation Level

2021 ◽  
Author(s):  
Jungang Wang ◽  
Kyriakos Balidakis ◽  
Maorong Ge ◽  
Robert Heinkelmann ◽  
Harald Schuh
Keyword(s):  
Polar Motion ◽  
Reference Frames ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Earth Orientation ◽  
Long Baseline ◽  
Space Geodetic Techniques ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Globally Distributed

<p>The terrestrial and celestial reference frames are linked by the Earth Orientation Parameters (EOP), which describe the irregularities of the Earth's rotation and are determined by the space geodetic techniques, namely, Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). The satellite geodetic techniques (SLR, GNSS, and DORIS) cannot determine the UT1-UTC or celestial pole offsets (CPO), rendering VLBI the only technique capable of determining full EOP set. On the other hand, the GNSS technique provides precise polar motion estimates due to the continuous observations from a globally distributed network. Integrating VLBI and GNSS provides the full set of EOP and guarantees a superior accuracy than any single-technique solution.</p><p>In this study we focus on the integrated estimation of the full EOP set from GNSS and VLBI. Using five VLBI continuous observing campaigns (CONT05–CONT17), the GNSS and VLBI observations are processed concurrently in a common least-squares estimator. The impact of applying global ties (EOP), local ties, and tropospheric ties, and combinations thereof is investigated. The polar motion estimates in integrated solution are dominated by the huge GNSS observations, and the accuracy in terms of weighted root mean squares (WRMS) is ~40 μas compared to the IERS 14 C04 product, which is much better than that of the VLBI-only solution. The UT1-UTC and CPO in the integrated solution also show slight improvement compared to the VLBI-only solution. Moreover, the CPO agreement between the two networks in CONT17, i.e., the VLBA and IVS networks, shows an improvement of 20% to 40% in the integrated solution with different types of ties applied.</p>

Sign in / Sign up

Export Citation Format

Share Document