Map-Aided Software Enhancement for Autonomous GNSS Complementary Positioning System for Railway

Abstract

Independently on the business case addressed, one of the main drawbacks of the railway use cases that need continuous Global Navigation Satellite Systems data is the lack of availability for the 100% of the time of the journey. Additionally, the integrity assessment of the position estimation given is also mandatory for safety critical applications. Thus, tunnels and multipath effects are one of the most challenging situations for the continuous positioning systems. In this context, an autonomous on-board Complementary Positioning System has been proposed to overcome the limitation of Global Navigation Satellite System based positioning systems. This paper proposes a positioning enhancement solution by means of fusing data from the satellite navigation system and inertial measurement units. That hybrid solution provides higher availability and accuracy to the positioning specially on known blocked scenarios, such as tunnels, or urban canyons, by means of a novel environment aware map aided software technique named Known Blocked Scenarios algorithm … This paper describes the Complementary Positioning System and the field test carried out in a challenging environment to validate the enhancement proposed by the authors, which demonstrate the benefits that this system has in known harsh environments for railways.

Precise Positioning of Autonomous Vehicles Combining UWB Ranging Estimations with On-Board Sensors

“…In some environments, such as urban canyons or tunnels, this can be a great challenge, since the satellite signals need to overcome numerous obstacles before reaching the vehicle's receiver. When GNSS signals are not available, the positioning is only based on the vehicle's inertial and odometry data [2]. Positioning estimates based on odometry and inertial estimates have a tendency to drift with time, increasing the positioning error.…”

Digital Filtering of Railway Track Coordinates in Mobile Multi–Receiver GNSS Measurements

“…This results from the fact that in this method, the time needed for precise geodetic coupling to physical infrastructure situated along the track is omitted, and the synchronized measuring signals are recorded with a relatively high frequency. In many countries, GNSS techniques are introduced to support determining of track coordinates; however, their use for accurate (in the global sense) mapping of track axis, especially in areas with varying access to satellites, is still a challenging issue [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. That is why the research project InnoSatTrack included an attempt to build a platform for multi–sensor track geometry measurement [ 35 ].…”