scholarly journals Area-Efficient Universal Code Generator for GPS L1C and BDS B1C Signals

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2737
Author(s):  
Jiwoon Park ◽  
Minsu Kim ◽  
Gwanghee Jo ◽  
Hoyoung Yoo
Keyword(s):  
Satellite System ◽  
High Accuracy ◽  
Code Generator ◽  
Universal Code ◽  
Code Generators ◽  
Area Problem ◽  
Legendre Sequence ◽  
Global Navigation Satellite ◽  
Single Receiver ◽  
Area Efficient

Recently, multi-frequency multi-constellation receivers have been actively studied, which are single receivers that process multiple global navigation satellite system (GNSS) signals for high accuracy and reliability. However, in order for a single receiver to process multiple GNSS signals, it requires as many code generators as the number of supported GNSS signals, and this is one of the problems that must be solved in implementing an efficient multi-frequency multi-constellation receiver. This paper proposes an area-efficient universal code generator that can support both GPS L1C signals and BDS B1C signals. The proposed architecture alleviates the area problem by sharing common hardware in a time-multiplex mode without degrading the overall system performance. According to the result of the synthesis using the CMOS 65 nm process, the proposed universal code generator has an area reduced by 98%, 93%, and 60% compared to the previous memory-based universal code generator (MB UCG), the Legendre-generation universal code generator (LG UCG), and the Weil-generation universal code generator (WG UCG), respectively. Furthermore, the proposed generator is applicable to all Legendre sequence-based codes.

scholarly journals Area-Efficient Universal Code Generator for Multi-GNSS Receivers

Electronics ◽  
2021 ◽  
Vol 10 (20) ◽  
pp. 2485
Author(s):  
Minsu Kim ◽  
Jiwoon Park ◽  
Gwanghee Jo ◽  
Hoyoung Yoo
Keyword(s):  
High Reliability ◽  
Global Navigation Satellite Systems ◽  
Linear Feedback ◽  
Receiver Design ◽  
Code Generator ◽  
Universal Code ◽  
Satellite Systems ◽  
Code Generators ◽  
Gnss Receivers ◽  
Area Efficient

Although conventional global navigation satellite systems (GNSS) receivers were originally designed for single signals, studies on multi-signal receiver design have recently been actively conducted to achieve high accuracy, precision, and reliability. However, in order for a multi-signal receiver to support various codes, the receiver should support the generation of individual codes. Therefore, the resulting problem of increased complexity must be solved. This paper proposes a hardware structure for an area-efficient linear feedback shift register (LFSR)-based multi-frequency universal code generator. Whereas the existing universal code generators were configured so that feedback polynomials, output registers, and initial values can be selected by placing read-only memories (ROMs), multiplexers (MUXs), and exclusive ORs (XORs) by register bit, in the case of the proposed universal code generator; the circuit was implemented by applying the hardwiring technique to those register bits that have fixed values. According to the results of field programmable gate array (FPGA) implementation, the proposed LFSR-based universal code generator can improve look up table (LUT) by up to 37% and register by up to 78% when compared to conventional code generators, and LUT by up to 36% when compared to the previous universal code generator. Therefore, the proposed universal code generator is a good candidate for implementing multi-frequency receivers to achieve high precision and high reliability.

scholarly journals Improving DGNSS Performance through the Use of Network RTK Corrections

2021 ◽  
Vol 13 (9) ◽  
pp. 1621
Author(s):  
Duojie Weng ◽  
Shengyue Ji ◽  
Yangwei Lu ◽  
Wu Chen ◽  
Zhihua Li
Keyword(s):  
Carrier Phase ◽  
Local Area ◽  
Satellite System ◽  
High Accuracy ◽  
Single Frequency ◽  
Baseline Length ◽  
Low Latitude ◽  
Phase Measurements ◽  
Network Rtk ◽  
Global Navigation Satellite

The differential global navigation satellite system (DGNSS) is an enhancement system that is widely used to improve the accuracy of single-frequency receivers. However, distance-dependent errors are not considered in conventional DGNSS, and DGNSS accuracy decreases when baseline length increases. In network real-time kinematic (RTK) positioning, distance-dependent errors are accurately modelled to enable ambiguity resolution on the user side, and standard Radio Technical Commission for Maritime Services (RTCM) formats have also been developed to describe the spatial characteristics of distance-dependent errors. However, the network RTK service was mainly developed for carrier-phase measurements on professional user receivers. The purpose of this study was to modify the local-area DGNSS through the use of network RTK corrections. Distance-dependent errors can be reduced, and accuracy for a longer baseline length can be improved. The results in the low-latitude areas showed that the accuracy of the modified DGNSS could be improved by more than 50% for a 17.9 km baseline during solar active years. The method in this paper extends the use of available network RTK corrections with high accuracy to normal local-area DGNSS applications.

scholarly journals Variability and Performance of Short to Long-Range Single Baseline RTK GNSS Positioning in Indonesia

2019 ◽  
Vol 94 ◽  
pp. 01012 ◽  
Author(s):  
Irwan Gumilar ◽  
Brian Bramanto ◽  
Fuad F. Rahman ◽  
I Made D. A. Hermawan
Keyword(s):  
Long Range ◽  
High Frequency ◽  
Carrier Phase ◽  
Satellite System ◽  
High Accuracy ◽  
Gnss Positioning ◽  
And Performance ◽  
Gnss Network ◽  
Single Baseline ◽  
Global Navigation Satellite

As the modernized Global Navigation Satellite System (GNSS) method, Real Time Kinematic (RTK) ensures high accuracy of position (within several centimeters). This method uses Ultra High Frequency (UHF) radio to transmit the correction data, however, due to gain and power issues, Networked Transport of RTCM via Internet Protocol (RTCM) is used to transmit the correction data for a longer baseline. This Research aims to investigate the performance of short to long-range single baseline RTK GNSS (Up to 80 KM) by applying modified LAMBDA method to resolve the ambiguity in carrier phase. The RTK solution then compared with the differential GNSS network solution. The results indicate that the differences are within RTK accuracy up to 80 km are several centimeter for horizontal solution and three times higher for vertical solution.

scholarly journals Ionospheric corrections tailored to the Galileo High Accuracy Service

2021 ◽  
Vol 95 (12) ◽  
Author(s):  
A. Rovira-Garcia ◽  
C. C. Timoté ◽  
J. M. Juan ◽  
J. Sanz ◽  
G. González-Casado ◽  
...  
Keyword(s):  
Satellite Orbit ◽  
Satellite System ◽  
High Accuracy ◽  
Integer Ambiguity ◽  
Electron Content ◽  
Confidence Bounds ◽  
Total Electron ◽  
Phase Measurements ◽  
Model Geometry ◽  
Global Navigation Satellite

AbstractThe Galileo High Accuracy Service (HAS) is a new capability of the European Global Navigation Satellite System that is currently under development. The Galileo HAS will start providing satellite orbit and clock corrections (i.e. non-dispersive effects) and soon it will also correct dispersive effects such as inter-frequency biases and, in its full capability, ionospheric delay. We analyse here an ionospheric correction system based on the fast precise point positioning (Fast-PPP) and its potential application to the Galileo HAS. The aim of this contribution is to present some recent upgrades to the Fast-PPP model, with the emphasis on the model geometry and the data used. The results show the benefits of integer ambiguity resolution to obtain unambiguous carrier phase measurements as input to compute the Fast-PPP model. Seven permanent stations are used to assess the errors of the Fast-PPP ionospheric corrections, with baseline distances ranging from 100 to 1000 km from the reference receivers used to compute the Fast-PPP corrections. The 99% of the GPS and Galileo errors in well-sounded areas and in mid-latitude stations are below one total electron content unit. In addition, large errors are bounded by the error prediction of the Fast-PPP model, in the form of the variance of the estimation of the ionospheric corrections. Therefore, we conclude that Fast-PPP is able to provide ionospheric corrections with the required ionospheric accuracy, and realistic confidence bounds, for the Galileo HAS.

High-Accuracy Optical Frequency Atomic Clock

2021 ◽  
Vol 30 (3) ◽  
pp. 2-7
Author(s):  
Myoung-Sun HEO ◽  
Dai-Hyuk YU ◽  
Won-Kyu LEE
Keyword(s):  
Atomic Clock ◽  
Satellite System ◽  
High Accuracy ◽  
Optical Frequency ◽  
Atomic Clocks ◽  
Navigation Satellite ◽  
Fundamental Constants ◽  
Quantum Metrology ◽  
Order Of Magnitude ◽  
Global Navigation Satellite

Frequencies have been the most accurately measured physical quantity since the second was defined in 1967 based on the microwave atomic transition of a Cs atom. Recently, atomic clocks using optical frequency transitions have shown an order of magnitude better accuracy than microwave clocks. Thanks to their high accuracy and resolution, atomic clocks have become a new tool for investigations involving fundamental science and technology, such as the search for dark matter, gravitational wave detection, the temporal variation of fundamental constants, relativistic geodesy, quantum metrology, and the advanced Global Navigation Satellite System (GNSS). In addition, a redefinition of the second based on the optical frequency is expected. In this paper, we review the principles and applications of optical clocks.

scholarly journals On the performance of GNSS levelling over steep slopes

2012 ◽  
Vol 18 (4) ◽  
pp. 645-660 ◽  
Author(s):  
R. Cuneyt Erenoglu ◽  
Mehmet Ali Yucel ◽  
Atinc Pirti ◽  
D. Ugur Sanli
Keyword(s):  
Satellite System ◽  
High Accuracy ◽  
Short Baseline ◽  
Solution Strategies ◽  
Baseline Solution ◽  
3D Positioning ◽  
3D Information ◽  
Global Navigation Satellite ◽  
Steep Slopes ◽  
New Strategies

In geodetic applications variety, one of the main current focuses is recently to determine the heights of ground stations with high accuracy. Specially the possibility of acquiring 3D information of the point positioning with high accuracy is opening up new strategies of investigating the heighting. Global Navigation Satellite System (GNSS) for 3D positioning is undergoing rapid developments and GNSS heighting can be an alternative to terrestrial techniques of height measurements. This paper presents a research study on the use of GNSS heighting in the case of steep slopes and multipath issue. Short baseline solution strategies were performed by using Bernese Software v. 5.0. The analysis results are also compared to the results of techniques of the terrestrial levelling. The results show that GNSS can be used as an practical surveying method to the terrestrial levelling with comparable accuracies. Furthermore, one can save up to 1 hour using GNSS instead of geometric levelling over a steep slope of a 100 m. On the other hand, as usual multipath is the primary error source decreasing the efficiency of GNSS, and it has been studied experimentally in this paper.

scholarly journals Background and Recent Advances in the Locata Terrestrial Positioning and Timing Technology

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1821 ◽  
Author(s):  
Chris Rizos ◽  
Ling Yang
Keyword(s):  
Literature Review ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
High Accuracy ◽  
Urban Environments ◽  
Navigation Satellite ◽  
Positioning Systems ◽  
Comprehensive Literature Review ◽  
The World ◽  
Global Navigation Satellite

Global Navigation Satellite System (GNSS) is the most widely used Positioning, Navigation, and Timing (PNT) technology in the world today, but it suffers some major constraints. Locata is a terrestrial PNT technology that can be considered as a type of localised “constellation”, which is able to provide high-accuracy PNT coverage where GNSS cannot be used. This paper presents a comprehensive literature review of the Locata technology and its applications. It seeks to answer questions, such as: (1) What is Locata and how does it work? (2) What makes Locata unique compared with other terrestrial positioning systems? (3) How has Locata been used in different applications for accurate PNT? (4) What are the current challenging issues that may restrict its further adoption for custom-grade navigation in urban environments?

scholarly journals Diagnostic Tools Using a Multi-Constellation Single-Receiver Single-Satellite Data Validation Method

2014 ◽  
Vol 68 (1) ◽  
pp. 196-214 ◽  
Author(s):  
Ahmed El-Mowafy
Keyword(s):  
Satellite Data ◽  
Satellite System ◽  
Diagnostic Tools ◽  
Data Validation ◽  
Test Statistics ◽  
Validation Parameters ◽  
Global Positioning ◽  
Gnss Measurements ◽  
Global Navigation Satellite ◽  
Single Receiver

The use of single-receiver single-satellite data validation parameters for numerical and graphical diagnostics of the multi-frequency observations is presented. This method validates Global Navigation Satellite System (GNSS) measurements of a single receiver where data from each satellite are independently processed using a geometry-free observation model with a reparameterised form of the unknowns. The method is applicable to any GNSS with any number of frequencies. The diagnostic tools are based on checking agreement of characteristics of the validation test statistics against theory. The use of these diagnostics in static and kinematic modes is demonstrated using multiple-frequency data from three GNSS constellations; Global Positioning System (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) and Galileo.

scholarly journals User-Oriented ICT Cloud Architecture for High-Accuracy GNSS-Based Services

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2635 ◽  
Author(s):  
Hossein Ghobadi ◽  
Paola Testa ◽  
Luca Spogli ◽  
Massimo Cafaro ◽  
Lucilla Alfonsi ◽  
...  
Keyword(s):  
Satellite System ◽  
Business Environment ◽  
High Accuracy ◽  
New Information ◽  
User Communities ◽  
Information And Communication ◽  
Ict System ◽  
Global Navigation Satellite ◽  
Downstream Market ◽  
Economic Outlook

We introduce a new information and communication technology (ICT) cloud-based architecture for Global Navigation Satellite System (GNSS) high-accuracy solutions, offering also a commercial overview of GNSS downstream market to show how the developed innovation is thought to fit in the real context. The designed architecture is featured by dynamic scalability, increased integrity, and greater agility of the ICT system. The novelty of the solution developed is a customized ICT architecture, obtained through unique and privileged access to user communities in the frame of the H2020 project TREASURE, allowing the development of a solution entirely driven by user needs. The economic outlook of GNSS downstream markets evolution highlights how the technology proposed effectively matches the evolving business environment, specifically in regard to the increasing need for flexibility and competitive advantage deriving from services. The simultaneous adoption of the technical and commercial perspective is meant to offer interesting findings to both the scientific community and GNSS industry, creating synergies previously unexplored.

scholarly journals LEO-Augmented GNSS Based on Communication Navigation Integrated Signal

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4700 ◽  
Author(s):  
Lei Wang ◽  
Zhicheng Lü ◽  
Xiaomei Tang ◽  
Ke Zhang ◽  
Feixue Wang
Keyword(s):  
Satellite System ◽  
High Accuracy ◽  
Good Choice ◽  
Low Earth Orbit ◽  
Noise Power ◽  
Communication Performance ◽  
Noise Power Spectral Density ◽  
Communication Signal ◽  
Navigation Signal ◽  
Global Navigation Satellite

Low Earth Orbit (LEO) is of great benefit for the positioning performance of Global Navigation Satellite System (GNSS). To realize the system of LEO-augmented GNSS, three methods to integrate communication and navigation signal for LEO communication system with the least influence on the communication performance are analyzed. The analysis adopts the parameters of IRIDIUM signal as restrictions. This paper gives quantitative comparison of these methods considering CN0(carrier noise power spectral density rate) margin, pseudorange accuracy, Doppler accuracy, and communication loss. For method 1, a low-power navigation signal is added to the communication signal. For method 2, the navigation signal is launched in one or more frames. For method 3, the navigation signal is launched in the frequency band separated to the communication signal. The result shows that the pseudorange accuracy of method 2 is far below method 1 and method 3. However, the difference of Doppler accuracy among the three methods can be emitted. Detailed analysis shows that method 1 is practicable when the communication and navigation signal power rate is 15 dB. It achieves the balance of pseudorange accuracy and bit error rate (BER) performance under this condition. Comprehensive comparison of these methods is given in the last. The result shows that the CN0 margin of the navigation signal for method 3 can be 13.04 dB higher than method 1, based on the accuracy threshold considered in this paper. Methods 1 and 3 have the advantage of high accuracy and high CN0 margin respectively. However, method 3 causes high communication capacity loss. Considering that the main disadvantage of GNSS signals is low CN0, method 3 is a good choice for the LEO-augmented GNSS system. Methods 1 and 3 can be combined to realize both high accuracy and high CN0 margin if possible.

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