Impact of Unknown Digital Map Errors on Satellite-based Navigation in Railway

Satellite navigation is considered one of the key technologies for future train control and railway signalling. Since Global Navigation Satellite System (GNSS) does not provide a location solution directly on the track domain, the use of a precise railway track map is essential to be integrated with GNSS. However, most current localization solutions assume that the track map, which relates the geographical position of the track with its unique location in the railway network, is perfectly known without any error. In this paper, we investigate and discuss the impact that digital track map errors can have on track-constrained GNSS positioning. First, we derive the mathematical basis that accounts for the propagation of map errors to the position solution. Then, we present the impact on the detection capability of pseudorange faults if these map errors are not known or ignored. The analysis show the importance of accounting properly for these errors to guarantee certain requirement levels

Detection of GNSS multipath with time-differenced code-minus-carrier for land-based applications

Ground transportation systems demand accurate and robust localizationfunctions. Satellite navigation is considered a key element in those systems, but its position determination can be highly corrupted in urban environments because of the presence of reflected signals (i.e. multipath). This paper deals with the detection of multipath in the code measurements of GNSS receivers for mobile users in urban scenarios. First, we discuss the different alternatives and limitations to properly isolate multipath autonomously at the receiver based on Code-Minus-Carrier (CMC) techniques in challenging GNSS applications.We then propose a practical methodology to design a suitable multipath detector based on the time difference of CMC. All the analysis and evaluations are supported with real measurements collected in Railway scenarios.This work has been funded by the European GSA H2020 project ERSAT-GGC. The authors would like to thank all the partners of the ERSAT-GGC consortium.Peer ReviewedPostprint (published version

Multisensor Localization Architecture for High-Accuracy and High-Integrity Land-based Applications

Emerging safety-related applications like autonomous vehicles will require high levels of navigation performance in terms of accuracy while still satisfying stringent requirements of integrity, availability and continuity. Achieving sub-meter accuracy in land-based scenarios with GNSS-based solutions can only be achieved with carrier-phase based approaches in combination with additional sensors. So that these solutions can be considered for future certified systems, the safety aspect must be ensured, which is still a challenge in the presence of local GNSS threats (like multipath or NLOS) as well as in multisensor architectures. In this work, we propose a multisensor architecture that uses float Real-Time Kinematic (RTK) GNSS with additional integrity information from an augmentation network. The architecture also considers different layers of protection against local GNSS threats that supports the rigorous design of integrity monitoring algorithms and protection level computation. GNSS is combined with additional sensors like Inertial Measurement Unit (IMU) and a robust relative location of the vehicle is complemented with stereo camera and vision processing. This allows for different possible types of localization modes. The algorithms are validated with real measurements collected with a car during a measurement in Rome, Italy. The results show clearly that our design can achieve high accuracy while ensuring high integrity

Effect of the strain Bacillus amyloliquefaciens FZB42 on the microbial community in the rhizosphere of lettuce under field conditions analyzed by whole metagenome sequencing

doi: 10.3389/fmicb.2014.00252 Effect of the strain Bacillus amyloliquefaciens FZB42 on the microbial community in the rhizosphere of lettuce under field conditions analyzed by whole metagenome sequencin

Towards recombinantly produced milk proteins: Physicochemical and emulsifying properties of engineered whey protein beta-lactoglobulin variants

DFG, 273937032, SPP 1934: Dispersitäts-, Struktur- und Phasenänderungen von Proteinen und biologischen Agglomeraten in biotechnologischen ProzessenBMBF, 031B0222, Basistechnologie Nachwuchsgruppe "Multiskalige Modellierung und Modifikation von Multienzymkomplexen als Basistechnologie für zellfreie Reaktionskaskaden" (II

Association between plasma phospholipid saturated fatty acids and metabolic markers of lipid, hepatic, inflammation and glycaemic pathways in eight European countries: a cross-sectional analysis in the EPIC-InterAct study.

BACKGROUND: Accumulating evidence suggests that individual circulating saturated fatty acids (SFAs) are heterogeneous in their associations with cardio-metabolic diseases, but evidence about associations of SFAs with metabolic markers of different pathogenic pathways is limited. We aimed to examine the associations between plasma phospholipid SFAs and the metabolic markers of lipid, hepatic, glycaemic and inflammation pathways. METHODS: We measured nine individual plasma phospholipid SFAs and derived three SFA groups (odd-chain: C15:0 + C17:0, even-chain: C14:0 + C16:0 + C18:0, and very-long-chain: C20:0 + C22:0 + C23:0 + C24:0) in individuals from the subcohort of the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study across eight European countries. Using linear regression in 15,919 subcohort members, adjusted for potential confounders and corrected for multiple testing, we examined cross-sectional associations of SFAs with 13 metabolic markers. Multiplicative interactions of the three SFA groups with pre-specified factors, including body mass index (BMI) and alcohol consumption, were tested. RESULTS: Higher levels of odd-chain SFA group were associated with lower levels of major lipids (total cholesterol (TC), triglycerides, apolipoprotein A-1 (ApoA1), apolipoprotein B (ApoB)) and hepatic markers (alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT)). Higher even-chain SFA group levels were associated with higher levels of low-density lipoprotein cholesterol (LDL-C), TC/high-density lipoprotein cholesterol (HDL-C) ratio, triglycerides, ApoB, ApoB/A1 ratio, ALT, AST, GGT and CRP, and lower levels of HDL-C and ApoA1. Very-long-chain SFA group levels showed inverse associations with triglycerides, ApoA1 and GGT, and positive associations with TC, LDL-C, TC/HDL-C, ApoB and ApoB/A1. Associations were generally stronger at higher levels of BMI or alcohol consumption. CONCLUSIONS: Subtypes of SFAs are associated in a differential way with metabolic markers of lipid metabolism, liver function and chronic inflammation, suggesting that odd-chain SFAs are associated with lower metabolic risk and even-chain SFAs with adverse metabolic risk, whereas mixed findings were obtained for very-long-chain SFAs. The clinical and biochemical implications of these findings may vary by adiposity and alcohol intake

A Robust and Effective GNSS/INS Integration Optimizing Cost and Effort

Meeting all requirements for ying approaches in bad weather conditions is one of the most demanding and challenging aspects of present day airborne navigation. Stand-alone satellite navigation has not yet reached the point of being suciently robust and accurate in order to reach certication level. Therefore, in this work the performance of an integrated satellite/inertial navigation system (GNSS/INS) is investigated in order to cope with short term losses of GNSS signals. We consider a low-cost Micro Electronic Mechanical System (MEMS) INS which is constantly reinitialized with information coming solely from GNSS. It takes over navigational responsibility when a loss of signal occurs or other failures in the satellite navigation system are detected. For the GNSS to provide all information necessary to initialize an INS, a minimum of three antennas is needed to measure the aircraft's attitude along with its speed and position. Error models for positioning, speed and attitude estimation are used to create a model for initialization uncertainties. Together with error models for the accelerometers and gyros in the Inertial Measurement Unit (IMU), the behavior of the whole proposed architecture is determined via performance simulations. As a maximum allowable error 15.3 meters (which corresponds to the CAT III horizontal alert limit for GNSS approaches) are taken. Our simulations show that this limit is not exceeded for at least 14 seconds after the take-over of navigational responsibility by the INS

Curvature Classification for Trains using Along-Track and Cross-Track Accelerometer and a Heading Rate Gyroscope

Real time curvature classification is crucial for all train localization problems. A reliable method to detected the track taken by the train after a switch is necessary and essential for train collision avoidance systems. At a larger scale, this should be included in a global surveillance system. In this paper, we discuss three possible track curvature detection methods based on two accelerometers and one gyroscope. We define and analyze corresponding test statistics that determine the actual track curvature. Given system safety requirements, i.e., maximum allowable probabilities of false alert and miss-detection, we derive a minimum detectable curvature difference (MDCD) between two possible tracks and compare these values with standard curvatures used in Germany. In this paper, it is shown that these MDCDs strongly depend on the sensor quality (for which an analytical form of the Gaussian error overbound of the sensor error is derived) and on the train dynamics (velocity). This analysis shows for two detectors very promising results and suggests a possible optimal combination of their test statistics

Cooperative Situation Awareness for a Railway Collision Avoidance System (RCAS)

This paper introduces a new approach addressing the problem of colliding trains. As opposed to "traditional" technical train safety systems, the approach does not require any technology in the infrastructure, i.e. along the railway track, but entirely relies on pervasive information and communication technology in the trains. The approach combines three core technologies: a direct train-to-train communication system, an accurate localization system and a cooperative situation analysis and decision support system. The system has been implemented and demonstrated with real trains, showing the huge potential for saving lives and avoiding damages