The ROADART project aimed for the development of a reliable, automated system for truck-to-truck (T2T) or truck-to-infrastructure (T2I) communication is safety, since a reliable T2TI/T2I communication platform can be used to warn professional drivers for immediate dangers and to provide crucial information for upcoming road conditions. In addition efficient and safe automated platooning systems drastically cut down GreenHouse Gas (GHG) and other pollutant emissions, while simultaneously they reduce the required transportation costs through fuel savings.

The novelties incorporated in the ROADART platform cover many areas. First of all is the pattern diversity concept, which was made feasible by implementing special reconfigurable antennas, the so called electronically switched parasitic radiator (ESPAR) antennas. Thus the system is adapted dynamically to its environment. The smart RF section cooperates with smart digital algorithms that run on software defined radios to select the best pattern combination and provide an efficient and reliable solution. Finaly a novel localization algorithm that is based on the input from the truck sensors offers high localization accuracy in environments where there is no navigation system available.

The designed and implemented antenna in the ROADART project is an electronically switched parasitic radiator (ESPARs). It provides pattern reconfigurability, low manufacturing costs, reduced complexity and smaller size. Thus the produced three radiation patterns from a single ESPAR allow for selecting the most suitable pattern configuration for a corresponding scenario. A pair of this antenna is mounted in each side mirror of the truck. Aside the antennas, the ROADART communication platform of each truck consists also of the following parts. First, two RF Modules (one per truck mirror) responsible for reception and transmission of the Truck-2-Truck Packets and part of the signal processing. And second, one communication unit (per truck), which is responsible for further processing and routing of the detected packets sent from the RF modules via Ethernet. Most of the software runs on the communication unit that among others includes the diversity engine, the ITS-G5 stack, the localization engine etc.

In ROADART, a novel Diversity Engine tailored-made for Truck-to-Truck (T2T) and Truck-to-Infrastructure (T2I) Communications was developed. The antenna (or spatial) diversity was used as the base of the diversity engine and additionally, a beampattern selection scheme was implemented with the use of reconfigurable antennas. The beampattern selection scheme was able to produce an omnidirectional pattern for broadcast - multicast transmission/reception as well as a directive pattern that can improve performance for several applications like CACC and platooning. The hybrid spatial-beamspace diversity scheme was implemented with the use of ESPAR Antennas with pattern selection capabilities.

An important and complicated objective of the project was the implementation of the Diversity Engine and especially the Dynamic Reconfiguration of the antennas for the ROADART platform in order to track the radio channel fluctuations in the complex T2T communications environment. Three dynamic reconfiguration modes were developed with full reconfiguration in all antennas and with omni support from one RF chain per mirror. The engine monitors continuously the SNR and reconfigures the patterns when it reduces below a threshold while reconfiguration is performed in two stages in order to ensure compatibility with the radio standard.

In ROADART, one of the developed and demonstrated diversity operation modes is the Geo-tracking, Geo-networking scheme. According to that, the patterns are selected based on the geometry of vehicles in a given time instance. This information is achieved through the ROADART localization engine, where each vehicle is aware of its position and additionally through the received ITS messages, which reveals the position of the cooperating vehicles. The engine calculates the relative heading angle between the vehicles and each vehicle decides on the combination of patterns that best fits the geometry of the vehicle. In this video, the behavior of the algorithm during an overtake maneuver that took place in the A55 Highway in Germany is presented.

A novel localization technique was developed in ROADART attempting to improve positioning performance in challenging conditions like tunnels. The Localization Engine, which is based on an Extended Kalman Filter, is able to operate with variable sampling rates of incoming data from various heterogeneous sources such as the GPS, Truck Sensors as well as positioning information from cooperating vehicles through ITS services. Then, the localization result is distributed to all interested parties with the use of the Data Distribution Service (DDS) protocol. The ROADART engine operated with less than 2m accumulated error for a 2km in-tunnel course during demonstration.

The focus of the time- and safety-critical Cooperative Adaptive Cruise Control (CACC) is to obtain robustness on the application layer against any wireless communication impairments, in particular packet losses and (time-varying) latency, utilizing ROADART communication system characteristics. The development of a model predictive controller (MPC) involves a prediction horizon, which may be used to predict the future output behavior of the leading vehicle. Thus CACC continues its functionality, increases the availability and robustness of the system by sharing look-ahead information and potentially enables shorter inter-vehicle following distances.

Join us at the workshop on “Real time ITS services towards a safer and more efficient road transport”
Place of the workshop: TRA conference venue, room Galerie 5+6.
Date: 17/04/2018, from 9:00 to 12:30

ROADART is attending EuCAP 2018 from 8-13 April 2018 and organize the session SW02 on "Multi-antenna concepts and communication techniques in C-ITS systems: From Theory to Application"