Reading RINEX 2.11 Observation Data Files
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... The observations mainly contain three main components: phase, time and pseudo-range. These values are stored in the Observation data file [13]. These observations should be corrected to avoid the external effects such as atmospheric refraction, clock offsets, etc. [13]. ...
... These values are stored in the Observation data file [13]. These observations should be corrected to avoid the external effects such as atmospheric refraction, clock offsets, etc. [13]. The positions of satellites can be computed with navigation messages sent from GNSS satellites, which are stored in Navigation file. ...
... The time of observations represent the time of the GNSS signals received by the receiver, which can be affected by clock offsets between satellites time stamp and that of receivers. Pseudorange of observations is defined as the distance between the receiver and the satellite with the consideration of clock offsets and other biases such as atmospheric delays [13]. The equation of pseudo-range is shown in Eq. (1) as follows. ...
Nowadays, the security of Global Navigation Satellite System (GNSS) has raised much more concerns due to the reliance on its position, velocity, and timing (PVT) information, which is of vital importance to various Internet of Things (IoT) systems, robotics, 5G technology and many applications of Intelligent Transportation Systems (ITSC). It has
been shown that GNSS system can be easily spoofed and masqueraded to provide ill intent payload damages. This paper proposes a novel algorithm based on unsupervised machine learning Gaussian Mixture Models (GMM) to provide antispoofing capability of GNSS signal such as GPS signal. It segregates GPS signals that are not under spoofing, from spoofed GPS signals that will result in malicious changes of pseudo-range measurements. It has been found out that the proposed GMM clustering algorithm is able to cluster the positions generated by the un-spoofed GPS signals properly and return the PRN (pseudorange noise) codes of the satellites without spoofing effectively. The proposed GMM clustering algorithm could cluster the
position points generated by non-spoofed signals properly by more than 90% and 77% accuracy for one and three spoofed satellites respectively.
... positioning epoch phase (RTK and Fast Static measurements) and data recording is a Trimble R10 dual-frequency (L1, L2) 492-band GNSS receiver (Table 3). The data was converted to Rinex 2.1 version (Pestana 2015). Following the conversion of a Rinex 2.1 file at geodetic point B10 with the Convert to Rinex programme, we wanted to have the same type of Rinex files from the three ROMPOS reference stations (ARAD, FAGE, and RESI) to use the same parameters (C1, C2, L1, L2, P1, P2, S1, S2) for post-processing ( The Stereographic Projection System 1970 is used as a reference system in Romania and Trimble Business Center (TBC) gives us the possibility to set this reference system before post-processing the GNSS data ( Figure 7). ...
... Coordinate System Setting using Trimble Business CenterTrimble Business Center (TBC) software enables surveyors to analyse and compensate for metadata, such as vector quality, then enhance raw observations with least squares or GNSS postprocessing (GNSS data processing from 12.02.2023 using Trimble Business Center Most geodetic processing software for GNSS data use a welldefined set of observables(Pestana 2015): The carrier-phase measurement at one or both carriers (being a measurement on the beat frequency between the received carrier of the satellite signal and a receiver-generated reference frequency). The pseudorange (code) measurement is equivalent to the difference between the time of reception (expressed in the time frame of the receiver) and the time of transmission (expressed in the time frame of the satellite) of a distinct satellite signal. ...
The techniques and tools developed for geodetic determinations have made it possible, over the past half century, to carry out measurements using global navigation satellite systems. As the accuracy and precision of positioning solutions, such as Fast Static and RTK, improve through technological advances, more applications will become available that can provide users with positioning information over time, autonomously verify the integrity of transmitted data, and ensure sufficient accuracy for their intended purposes. In our study for the interpretation, analysis, and visualization of raw and/or processed RINEX GNSS data recorded over time at a geodetic point using the information available from the Fast Static technique, we used the GeoRinex library from the Python programming language. This library converts data to xarray.data set, for easy use in processing parameter sets, from Rinex files: of ROMPOS reference stations and of the new B10 point resulting from measurements using the Fast Static technique: pseudorange (C1, C2, P1, P2....), carrier phase (L1, L2,…), doppler (D1, D2....) and signal strength (S1, S2....). All this information will help us to analyse and interpret the degradation of the parameters associated with Rinex version 2.11 epoch positioning files 12.02.2023, time interval 12:00-14:00 (fast static) and to understand their accuracy and behavior in different environments. Based on this study, our aim was to evaluate the error in determining the positioning accuracy of the B10 point located in a crowded and heavily trafficked area, which allows sufficient coverage of the GNSS satellites.
... Let us analyze the real GNSS hardware noise immunity attained when processing signals by new-generation GPS satellites. The data from measuring radio-navigation parameters in the RINEX format contain parameter S (Pestana 2015). The latter, as per the RINEX 3.03 specification (ftp://igs.org/pub/data/format/rinex303.pdf), ...
To provide GNSS/SBAS reliable performance under Space Weather impacts several solutions are considered. The system of technical-organizing measures that will enable to improve the GNSS performance quality with allowance for current helio-geophysical conditions is proposed. Exact fore- and nowcasting positioning quality under geomagnetic disturbances is out of modern state of technologies. Nevertheless, the forecasting may be proposed as a general measure to alert GNSS\SBAS users for the probable abnormal state of the positioning in advance and in the nearly-real time. Real-time alert of users to a geomagnetic disturbance in the signal propagation medium is considered as enhancement of RAIM solutions. A complex system of differential correction, prediction, and monitoring of the GNSS positioning quality under unfavorable helio-geophysical conditions is proposed. The system is considered as a basis for a perspective service of global monitoring and forecasting of the integrated uniform GNSS current operation quality.
... Let us analyze the real GNSS hardware noise immunity attained when processing signals by new-generation GPS satellites. The data from measuring radio-navigation parameters in the RINEX format contain parameter S (Pestana 2015). The latter, as per the RINEX 3.03 specification (ftp://igs.org/pub/data/format/rinex303.pdf), ...
GNSS technologies have outgrown their initial purpose (providing navigation itself) and become one of the driving factors in the international technological progress. Thereby, providing the required quality of GNSS measurements to solve applied and research issues acquires a special urgency. Hence, there comes a fundamental scientific problem. One should reveal and produce quantitative–qualitative estimates for prevalent radio physical and radio technical mechanisms and typical regularities of GNSS characteristic degradation under the impact from space weather.
The goal of this monograph is to provide an extensive worldwide notion about the up-to-date status of GNSS scientific and technological development and investigations into the above fundamental and applied problems. We discuss possible trends to improve scientific-methodical and hardware-software GNSS means (as well as their applications) with allowance for space weather extreme factors.
... Let us analyze the real GNSS hardware noise immunity attained when processing signals by new-generation GPS satellites. The data from measuring radio-navigation parameters in the RINEX format contain parameter S (Pestana 2015). The latter, as per the RINEX 3.03 specification (ftp://igs.org/pub/data/format/rinex303.pdf), ...
GNSS performance is examined under both extreme and dangerous solar radio bursts and strong magnetic storms during the period from 2001 till 2020. Our experimental observations corroborate a negative effect of space weather factors on GNSS operation in the stand-alone and differential navigation modes. It was proved that the main causes of that are: (1) GNSS signal direct suppression from solar L-band radio bursts with a >103 s.f.u.; (2) signal ionospheric scintillations in the regions and time when higher values for the electron density gradients are registered (auroral oval south border, equatorial super-bubbles distribution area, main phase of magnetic storm at mid latitudes).
... Amplitude of cosine harmonic correction term to the argument of latitude (Pestana, 2015) Derivation of equation 1 to 16 uses the symbols in Table 2. ...
Broadcast orbits are compared against final orbit to get the error of broadcast orbit. The errors are analysed by presenting the error over space, especially longitude. The satellite trajectory is divided into three sector namely northern, southern, and transitional sectors. Spatial analysis show that the error is correlated with the latitude and longitude. Some consistency pattern can be observed from the distribution of the error in the spatial analysis. Standard deviation (SD) is used to quantify the consistency, providing more quantitative insights into the spatial analysis. Four patterns can be observed in the error distribution, namely consistency in northern and southern sector, consistency of transitional sector, changes after transitional sector, and correlation between ΔX component and ΔY component. The spatial analysis shows potential to be used in broadcast orbit error estimation and prediction. A model that uses this predicted broadcast orbit error as a correction will be designed in the future to improve the broadcast orbit accuracy.
... The position of the RTK base station can be determined with the addition of satellite phase bias information with a method termed Precise Point Positioning (PPP) [9]. The RINEX standard [10] is used to store positional and navigational data for this purpose, which include meteorological data and GNSS observations such as the code, phase, Doppler and time. ...
Centimetre accurate geolocation service is beneficial to a wide range of applications, ranging from sports engineering, civil infrastructure, autonomous vehicles, surveying to digitisation of historically significant structures. Previously, these features were confined to prohibitively expensive commercial hardware, requiring technical knowledge and experience to operate. Continued technological advancements have seen the miniaturisation of electronics and antennas, coupled with an increase in the number and performance of global navigation satellite systems (GNSS) by various nations and organisations, providing global signal coverage. This paper demonstrates a low-cost, mobile, real-time kinematic (RTK) geolocation service for engineering and research applications, fabricated from components readily available from commercial suppliers. This solution, consisting of a mobile RTK base station and RTK rover, provides centimetre-accuracy performance up to a distance of 15 km away from the base station. Correction data is transmitted over the internet using free and open software solutions. The small footprint of both the RTK base station and RTK rover, provides versatile applications even in remote locations. The performance of the geolocation service is validated using field experiments, comparing measurements against state-of-the-art photogrammetry, light detection and ranging (LiDAR) and digital level measurement technologies. The authors encourage the adoption of the RTK geolocation solution based on the calibrated results.
... GNSS data distributed in RINEX format contain S parameters (Pestana 2015) that represent the carrier-to-noise power density ratio (C/N0) or raw signal strength according to the RINEX 3.03 specification (ftp://igs.org/pub/ data/forma t/rinex 303.pdf). ...
A Solar Radio Burst (SRB) is one of the most severe natural hazards affecting the performance of the global navigation satellite systems (GNSS). Considering the influence of different threat factors, the GNSS developers upgrade the systems to amend the accuracy and noise-proof features of the systems. In particular, GPS gradually replaces “old” satellites (GPS IIA, GPS IIR-A, GPS IIR-B) with new-generation equipment (GPS IIR-M, GPS IIF, GPS III) featured by an increase in the emitted signal power at L2 frequency and by new civilian codes. In this work, based on examples of the extreme SRB of September 24, 2011, and the severe SRB of September 6, 2017, we study how such modernization can improve the GPS system performance during solar flares accompanied by intense SRB. We recorded SRB-related drops in signal strength (S), which were 7.5/0 dB-Hz for the S1C, 10/7 dB-Hz for the S2X, 17/8 dB-Hz for the S2W and 9/7.5 for the S5/S5X in 2011/2017 correspondingly. The drop in the S2W signal strength for the modernized blocks was comparable in amplitude to those of the “old” blocks. However, the modernized IIR-M/IIF blocks were featured by about 5 dB-Hz higher signal strength. This resulted in a double and triple decrease in loss-of-lock density for the IIR-M/IIF satellites in 2011 and 2017, respectively, as compared to IIA/IIR-A during SRBs. Therefore, the increase in the emitted signal power and new civilian codes potentially enhance the stability of the GPS operation.
... and navigation (RINEX.n) files [21,22]. The positioning solutions were calculated according to the standard Single Point Positioning (SPP) process. ...
Global and regional positional accuracy assessment is of the highest importance for any satellite navigation system, including the Global Positioning System (GPS). Although positioning error can be expressed as a vector quantity with direction and magnitude, most of the research focuses on error magnitude only. The positional accuracy can be evaluated in terms of navigational quadrants as further refinement of error distribution, as it was shown here. This research was conducted in the wider area of the Northern Adriatic Region, employing the International Global Navigation Satellite Systems (GNSS) Service (IGS) data and products. Similarities of positional accuracy and deviations distributions for Single Point Positioning (SPP) were addressed in terms of magnitudes. Data were analyzed during the 11-day period. Linear and circular statistical methods were used to quantify regional positional accuracy and error behavior. This was conducted in terms of both scalar and vector values, with assessment of the underlying probability distributions. Navigational quadrantal positioning error subset analysis was carried out. Similarity in the positional accuracy and positioning deviations behavior, with uneven positional distribution between quadrants, indicated the directionality of the total positioning error. The underlying distributions for latitude and longitude deviations followed approximately normal distributions, while the radius was approximated by the Rayleigh distribution. The Weibull and gamma distributions were considered, as well. Possible causes of the analyzed positioning deviations were not investigated, but the ultimate positioning products were obtained as in standard, single-frequency positioning scenarios.
From definitions of a geodetic CORS system to examples of tracking networks around the world and raw data exchange formats, this chapter highlights the ground-based infrastructure for collecting continuous tracking data from the earth-orbiting satellites. Such infrastructure, having increased over the years, is run by various agencies, organizations, and institutions to enable the science and practice of GNSS geodesy. The primary product from the CORS infrastructure is the satellite tracking data, archived in standard raw data exchange formats such as RINEX, for subsequent modeling and estimation of station coordinates and velocities, satellite orbits, clock products, reference frames, and other related products.
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