GNSS augmentation

About: GNSS augmentation is a research topic. Over the lifetime, 2478 publications have been published within this topic receiving 28513 citations. The topic is also known as: SBAS & Satellite Based Augmentation System.

Lane-level map-matching with integrity on high-definition maps

Abstract: Navigation maps provide important information for Advanced Driving Assistance Systems (ADAS) and Autonomous Vehicles. This paper presents a method estimating a set of likely map-matched hypotheses containing the correct solution with a high probability. This addresses the problems encountered when using a high definition map when a large number of ambiguities arise. These occur for instance, when only inaccurate prior information on position is available at initialization. The method uses lane-level accurate maps with dedicated attributes, such as connectedness and adjacency, and an automotive Global Navigation Satellite System (GNSS) receiver assisted with dead-reckoning (DR) sensors. GNSS can be so inaccurate that map-matching relies mainly on DR estimates, the GNSS fixes being used as uncertain estimates with protection levels. This paper proposes a formalization of the map-matching integrity problem as well as a sequential method using a Particle Filter providing a reliable set of map-matched hypotheses. The performance is evaluated using data acquired in public roads.

Impact and mitigation of space weather effects on GNSS receiver performance

Abstract: It is well known that Global Navigation Satellite System (GNSS) signals suffer from a number of vulnerabilities, out of which a potential severe vulnerability is the effect of space weather. Space weather effects on the signals transmitted by GNSS include the effect of ionospheric perturbations and solar radio bursts. Intense solar radio bursts occurring in the L-band can impact the tracking performance of GNSS receivers located in the sunlit hemisphere of the Earth and are therefore a potential threat to safety-critical systems based on GNSS. Consequently monitoring these events is important for suitable warnings to be issued in support to related services and applications. On the other hand, the space weather effects leading to ionospheric perturbations on the GNSS signals are either due to dispersion or scintillation caused by plasma density irregularities. Scintillation can cause cycle slips and degrade the positioning accuracy in GNSS receivers. The high-latitude scintillation occurrence is known to correlate with changes in the solar and interplanetary conditions along with a consequential impact on GNSS receiver tracking performance. An assessment of the GNSS receiver tracking performance under scintillation can be analysed through the construction of receiver phase-locked loop (PLL) tracking jitter maps. These maps can offer a potentially useful tool to provide users with the prevailing tracking conditions under scintillation over a certain area and also be used to help mitigate the effects of scintillation on GNSS positioning. This paper reviews some of recent research results related to the impact and mitigation of space weather effects on GNSS receiver performance.

Observations of low-elevation ionospheric anomalies for ground-based augmentation of GNSS

Abstract: [1] Extreme ionospheric anomalies occurring during severe ionospheric activity can pose an integrity threat to users of Global Navigation Satellite System (GNSS) Ground Based Augmentation Systems (GBAS). While most very large spatial gradients in slant ionospheric delay were observed on high-elevation satellites, several extreme gradients were also observed on satellites below 15 degrees elevation. This paper details the study of anomalous ionospheric spatial gradients for low-elevation satellites observed from the 20 November 2003 geomagnetic storm in the Conterminous United States (CONUS). As viewed by a cluster of Continuously Operating Reference Stations (CORS) receivers in northern Ohio, SVN 26 came into view around 20:30 Universal Time (UT) on this day, rose to an elevation angle of about 15 degrees, and set around 22:00 UT. A spatial gradient of 360 mm/km was discovered at 21:20 UT between CORS stations GARF and WOOS, when SVN 26 was at 11 degrees elevation. Ionospheric delay measurements are vulnerable to semi-codeless L2 tracking errors and data post-processing errors, especially when satellites are at low elevation. This paper presents a series of methods to validate observed ionospheric anomaly events using station-wide checks, satellite-wide checks, and manual verification with single-frequency measurements. Spatial gradients discovered at other station pairs and another low elevation satellite with a similar azimuth angle, SVN 29, support that the event of SVN 26 is an ionospheric anomaly as opposed to a receiver fault.

A performance analysis of future global navigation satellite systems

Abstract: For an increasing number of applications, the performance characteristics of current generation Global Navigation Satellite Systems (GNSS) cannot meet full availability, accuracy, reliability, integrity and vulnerability requirements. It is anticipated however that around 2010 the next generation of GNSS will offer around one hundred satellites for positioning and navigation. This includes constellations from the US modernised Global Positioning System, the Russian Glonass, the European Galileo, the Japanese Quasi- Zenith Satellite System and the Chinese Beidou. It is predicted that the performance characteristics of GNSS will be significantly improved. To maximise the potential utility offered by this integrated infrastructure, this paper presents an approach adopted in Australia to quantify the performance improvements that will be available in the future. It presents the design of a GNSS simulation toolkit developed in Australia and the performance expectations of future GNSS for a number of important applications within the Asia Pacific region. In quantifying the improvement in performance realised by combined systems, this paper proposes a practical approach to facilitate the development of innovative applications based on future GNSS.

Car navigation system and method in which global navigation satellite system (gnss) and dead reckoning (dr) are merged

Abstract: Disclosed is a car navigation system and method. The present invention includes a sensor unit including a plurality of sensors, each, configured to measure a state of a vehicle using a predetermined scheme and to obtain sensor data; a vehicle to everything (V2X) unit configured to receive the sensor data from the sensor unit, and including a global navigation satellite system (GNSS) module to thereby receive a satellite signal and to generate GNSS data; and a position estimator configured to receive the sensor data and the GNSS data from the V2X unit, to evaluate an accuracy of each of the sensor data and the GNSS data using a predetermined scheme, and to obtain position coordinates of the vehicle by merging GNSS position coordinates obtained from the GNSS data and dead reckoning (DR) position coordinates obtained from the sensor data based on the evaluation result.