PVT Solution Research Articles

Improved high‐precision GNSS navigation with a passive hydrogen maser

<h3>Abstract</h3> Receiver clock modeling (RCM) based on code observations requires a chip-scale atomic clock to improve the PVT solution. When using carrier phase observations, a more stable oscillator like a passive hydrogen maser (PHM) is necessary. We applied a PHM in an automotive experiment of about 80 minutes in an urban environment recording 10 Hz multi-GNSS data. Modeling the clock process noise in a linearized Kalman filter according to the spectral behavior of the PHM (i.e., RCM), improves position and velocity regarding precision and accuracy by 15% and 57%, respectively, as well as reliability by 30%. In situations with sparse, geometrically unfavorable observations, RCM prevents large position drifts. The convergence time of the carrier phase ambiguities is not affected. Conclusively, precision, accuracy, and reliability in kinematic precise point positioning can be improved by using an oscillator like a PHM. Future advancements in clock technology should make this approach more feasible for ordinary use cases.

COTS based GNSS Receiver with Precise Point Positioning for CubeSats

The paper presents the work towards developing a COTS based GNSS receiver and integrating Precise Point Positioning algorithms to facilitate close proximity operations for CubeSats in formation flying and during docking or rendezvous manoeuvres. We initially present the driving requirements identified for these types of missions. Besides fitting a standard CubeSat, the receiver has to weigh less than 0.3 kg, consume less than 5 W and be multi-frequency and multi-onstellation. Next, follows the identification of a commercial off the shelf GNSS receiver that can be easily customized to fit the basic requirements of a GNSS space receiver and on which Precise Orbit Determination (POD) algorithms can be implemented. For the start of the activity three commercial receivers were selected as proposed candidates to be traded off regarding the degree to which they fulfil the requirements, the degree of openness and of manufacturer support. A COTS microcontroller shall be then selected to control the operation of the COTS receiver. We then expand on the proposed general architecture of the system from COTS modules to their integration philosophy, with a discussion on the means of delivering the correction factors to the receiver. PPP corrections are expected to be delivered either via ground stations or via the geostationary satellite based commercial services. The PPP algorithms are to be implemented on the microcontroller, which will also try to maximize the availability of a precise PVT solution by incorporating a neural network fed by an orbit propagator and the PPP algorithm. The neural network shall estimate a precise position whenever PPP corrections are not available. The training of the neural network shall be done on the ground, allowing for a small footprint on board. A preliminary design of the hardware and the planned qualification plan is concluding the work.

Track Constrained RTK-like Positioning for Railway Applications

Here, we investigate PVT solutions based on multi-constellation receivers and dedicated augmentation networks allowing to determine the track on which a train is operating with a very high safety Integrity level. Because the time needed to accomplish this task has a relevant impact on the rail traffic management performance and, therefore, it is considered a key performance indicator by rail infrastructure managers, a double frequency solution is investigated. Particularly, we focus our attention on the advantages of relative positioning solutions, based on Double-Difference Wide-Laning Carrier Phase measurement combination, exploiting the fact that the train location is completely determined by its mileage due to the track constraint, to speed up track discrimination. No ambiguity fix is required at this scope. Here, a detailed description of the overall processing and achievable performance is given. Performance assessment is provided by means of Monte Carlo simulations based on observations recorded on field campaigns.

Research on PVT Solution Methods for Navigation Message of GPS Receiver

On the basis of the analysis of PVT solution methods for navigation message, the solution procedure of evaluation algorithm of LSM and Kaman filtering evaluation algorithm is constructed. Further, based on OEM development board for data acquisition, PVT solution process of collected GPS signals is simulated, and the results show that the solution property of Kaman filtering algorithm is much better than LSM. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.4177

Analytical 2D GNSS PVT solutions from a hyperbolic positioning approach

GNSS receivers estimate 3D antenna position and receiver clock bias when at least four satellites are tracked. If only three satellites are available, a 2D antenna position solution is still possib...

Global positioning: technologies and performance

Foreword. Acknowledgements. Preface. Chapter 1. A brief history of navigation and positioning. 1.1 The first age of navigation. 1.2 The age of the great navigators. 1.3 Cartography, lighthouses and astronomical positioning. 1.4 The radio age. 1.5 The first terrestrial positioning systems. 1.6 The era of artificial satellites. 1.7 Real-time satellite navigation constellations today. 1.8 Exercises. Bibliography. Chapter 2. A brief explanation of the early techniques of positioning. 2.1 Discovering the world. 2.2 The first age of navigation and the longitude problem. 2.3 The first optical based calculation techniques. 2.4 The first terrestrial radio based systems. 2.5 The first navigation satellite systems: TRANSIT and PARUS/TSIKADA. 2.6 The second generation of navigation satellite systems: GPS, GLONASS and Galileo. 2.7 The forthcoming third generation of navigation satellite systems: QZSS and COMPASS. 2.8 Representing the world. 2.9 Exercises. Bibliography Chapter 3. Development, deployment and current status of satellite based navigation systems. 3.1 Strategic, economical and political aspects. 3.2 The global positioning satellite systems: GPS, GLONASS and Galileo. 3.2.1 The Global Positioning System : GPS. 3.2.2 The GLONASS. 3.2.3 Galileo. 3.3 The GNSS1: EGNOS, WAAS and MSAS. 3.4 The other satellite based systems. 3.5 Differential satellite based commercial services. 3.6 Exercises. Bibliography. Chapter 4. Non-GNSS positioning systems and techniques for outdoors. 4.1 Introduction (large area without contact or wireless systems). 4.2 The optical systems. 4.3 The terrestrial radio systems. 4.4 The satellite radio systems. 4.5 Non-radio based systems. 4.6 Exercises. Bibliography. Chapter 5. GNSS system descriptions. 5.1 System description. 5.2 Summary and comparison of the three systems. 5.3 Basics of GNSS positioning parameters. 5.4 Introduction to error sources. 5.5 Concepts of differential approaches. 5.6 SBAS system description (WAAS and EGNOS). 5.7 Exercises. Bibliography. Chapter 6. GNSS navigation signals: description and details. 6.1 Navigation signal structures and modulations for GPS, GLONASS and Galileo. 6.2 Some explanations of the concepts and details of the codes. 6.3 Mathematical formulation of the signals. 6.4 Summary and comparison of the 3 systems. 6.5 Developments. 6.6 Error sources. 6.7 Time reference systems. 6.8 Exercises. Bibliography. Chapter 7. Acquisition and tracking of GNSS signals. 7.1 Transmission part. 7.2 Receiver architectures. 7.3 Measurement techniques. 7.4 Exercises. Bibliography. Chapter 8. Techniques for calculating positions. 8.1 Calculating the PVT solution. 8.2 Satellite's position computations. 8.3 Quantified estimation of errors. 8.4 Impact of pseudo range errors on the computed positioning. 8.5 Impact of geometrical distribution of satellites and receiver (notion of DOP). 8.6 Benefits of augmentation systems. 8.7 Discussion on interoperability and integrity. 8.8 Effect of multipath on the navigation solution. 8.9 Exercises. Bibliography. Chapter 9. Indoor positioning problem and main techniques (Non-GNSS). 9.1 General introduction to indoor positioning. 9.2 A brief review of possible techniques. 9.3 Network of sensors. 9.4 Local area telecommunication systems. 9.5 Wide-area telecommunication systems. 9.6 Inertial systems. 9.7 Recap tables and global comparisons. 9.8 Exercises. Bibliography. Chapter 10. GNSS-based indoor positioning and a summary of indoor techniques. 10.1 HS-GNSS. 10.2 A-GNSS. 10.3 Hybridization. 10.4 Pseudolites. 10.5 Repeaters. 10.6 Recap tables and comparisons. 10.7 Possible evolutions with availability of the future signals. 10.8 Exercises. Bibliography. Chapter 11. Applications of modern geographical positioning systems. 11.1 Introduction. 11.2 A chronological review of the past evolution of applications. 11.3 Individual applications. 11.4 Scientific applications. 11.5 Applications for public regulatory forces. 11.6 Systems under development. 11.7 Classifications of applications. 11.8 Privacy issues. 11.9 Current receivers and systems. 11.10 Conclusion and discussion. 11.11 Exercises. Bibliography. Chapter 12. The forthcoming revolution. 12.1 Time and space. 12.2 Development of current applications. 12.3 The possible revolution of everybody's daily life. 12.4 Possible technical positioning approaches and methods for the future. 12.5 Conclusion. 12.6 Exercises. Bibliography. Index.