January 19, 2021: An ESA-supported effort put an intelligent road up in Finnish Lapland through its paces, assessing its suitability for testing autonomous vehicles in some of Europe’s most challenging driving conditions. 1)
Background: The development of highly automated vehicles enables safer, more efficient and environmentally friendly road transport in the future. In order for automated vehicles to reach their full potential, year-round operation in extreme weather conditions is required. 2)
The aim of the Arctic Challenge project was to study automated driving in snowy and icy northern conditions. This Finnish public road authorities and EU CEF (Connecting Europe Facility)-funded project included three industry coalitions that were selected in a public procurement process to study four research questions in Arctic conditions related to posts and poles for guidance and positioning, Cooperative Intelligent Transport Systems (C-ITS), communication infrastructure and remote driving, as well as vehicle positioning.
The Lapland University of Applied Sciences and Roadscanners study of posts and poles in Arctic conditions contributed to the understanding of the prospects and limitations of current technologies and products in the field of autonomous driving, with a focus on radars and passive reflectors. The results indicated that shifting snow weakens the detected signal of the reflector poles and the 20 m pole intervals are considered advantageous at 80 km/h speeds in traffic with other vehicles possibly blocking the signal. The results give a positive prognosis for developing radar reflectors further and making them smaller in size for more practical and cost effective applications.
The VTT Technical Research Centre of Finland, Dynniq, Infotripla and Indagon consortium focused on Cooperative ITS (C-ITS) services in arctic conditions. The results indicate that the hybrid communication solution of ITS-G5 and LTE (Long-Term Evolution) radio communication technologies used for the transmission of four Day 1 messages of stationary vehicle, animal on the road, slippery road and roadworks warnings, are functional under arctic conditions. Exchange of C-ITS (Cooperative Intelligent Transport Systems) messages between several operators is a prerequisite for the implementation of an efficient information and warning service with cross-border interoperability. The solution for delivery of Day-1 messages based on ETSI (European Telecommunication Standards Institute) ITS-G5 was found to be more mature at the time when tests were carried out, but it provides more limited geographical coverage compared to cost of implementation than the solution based on commercial LTE networks.
The Sensible 4 consortium focused on three research questions: How active poles could be utilized for guiding automated vehicles in difficult conditions, the remote control of automated vehicles in harsh conditions and the loss of road lane markings and GNSS, and how can automated vehicles localize themselves in such situations. As a result of the project it has been shown that UWB (Ultra -WideBand) technology can offer a positioning accuracy of a few centimeters, and remote control can be a viable method for borderline cases if minimum network requirements are met. Lidar-based positioning can be a primary positioning method, even in Arctic conditions. The solution used by Sensible 4, combining multiple sensors as well as non-linear algorithms with satellite information, yield a reliable positioning performance of an automated vehicle with a maximum average error of 0.264 m and lateral error of 0.187 m in all conditions using a single HD map.
The development of autonomous driving systems should be continued to better ensure performance in harsh weather conditions. This requires the development of both hardware and software, and collaboration between industry and the public sector.
Lapland is known for its Arctic vehicle testing conditions, cutting edge expertise and facilities, such as test tracks. The most significant centers specializing in vehicle, tire and component testing operations are located in Muonio, Ivalo and Rovaniemi. 3)
Snowbox, the Arctic test area designed for testing and researching traffic automation and self-steering vehicles, is located in Fell Lapland, which features an approximately ten-kilometer section of public road instrumented for this purpose, among other facilities.
A test team from the self-driving technology company Sensible 4 is traveling to the Finnish arctic area of Muonio to perform a 2-week-long autonomous winter driving test in dark and snowy conditions. The goal of the autonomous driving testing is to collect winter data and ascertain how new features in their software perform in harsh winter conditions. 4)
Managing harsh weather conditions is a requirement to make autonomous vehicles fully functional. “Bad weather is one of the biggest challenges for autonomous vehicles. Our strength is to cope with varying weather conditions, and, if the software works in difficult Finnish conditions, it will work also in sunny California,” says Tommi Rimpiläinen, the chief operating officer of Sensible 4, which develops software for all-weather autonomous vehicles and has headquarters in the Helsinki area. “Lapland has the best possible winter testing conditions for autonomous vehicles. It provides low temperatures, snow, and darkness, which is good for testing driving and sensor technology even in extreme conditions.”
“Our project aimed at ensuring in particular that the precise positioning required by autonomous systems was available here, to establish this test site is indeed somewhere that driverless vehicle manufacturers should employ for testing. We carried out experiments with a robotic car over two successive seasons to show that the necessary precise positioning, down to 20 cm, is indeed accessible.”
Known as Snowbox, this 10-km stretch of forest-lined roadway on Finland’s E8 highway has been specially equipped for autonomous driving tests. Containing cameras, ‘laser radar’ lidar, ultra-wideband antennas and reflective panels, the road itself is underpinned by power and fibre optic lines, and embedded with pressure sensors to record road surface conditions and the speed and type of vehicles driving along it.
Snowbox is also linked to the FinnRef network of satellite navigation reference stations, to deliver corrections for precise satnav positioning. By performing positioning measurements continuously at fixed locations, these reference stations serve as a standard, allowing the identification of measurement errors to boost positioning accuracy on a localized basis.
“The Arctic is a difficult environment for autonomous driving in general,” adds Dr. Thombre.
“Signal disturbance due to the ionosphere, the electrically charged layer of the atmosphere, degrade satellite navigation performance. This effect is more pronounced in the Arctic region. And satnav augmentation systems also face challenges.
“Because their signals are broadcast from geostationary satellites, they are only viewable here at an elevation of up to 10 degrees above the horizon. And mobile coverage – useful for providing correction data from reference networks – is also inconsistent.
“In addition, possibility of mists and fog, snowstorms and rainfall make it difficult for cameras and lidar, while ice and snow on the road means wheel speed sensors may slip. And temperatures that can plunge down to below -30°C can impede the performance of electronics.”
The Arctic-PNT team’s testing was based around a robotic car crammed with sensors and recording equipment. Called Martti, the vehicle was supplied by Finland’s VTT Technical Research Centre.
“While Martti is capable of autonomous driving, we drove it manually,” explains Dr. Thombre. “We were using it to capture all the data we needed. We started off using solely satellite navigation – including Europe's Galileo and EGNOS – progressively adding more and more augmentation data, including in-car sensors, and corrections from the FinnRef stations, to reach the all-important precise positioning threshold of 20 cm.
“To access the FinnRef corrections from the car systems we tested out various mobile sim cards. Adding to the challenge, we crossed an international border, because part of the E8 highway is instrumented on the Norwegian side as well – called Borealis.”
The Snowbox infrastructure was established along the E8 because, while it is a remote roadway it is also economically important, with trucks heading south from Arctic fisheries.
The Arctic-PNT test campaigns, starting from 2018, gave a positive bill of health to the Snowbox, which is available for experiment campaigns. The campaigns were supported through ESA’s strategic initiatives for the Arctic region.
ESA’s NAVISP (Navigation Innovation and Support Program) – developing new future positioning, navigation and timing technologies and services – now offers the opportunity for industry and national institutions to undertake similar initiatives.
NAVISP Element 2 is focused on European competitiveness in positioning, navigation and timing, while Element 3 gives support to Member States on their national navigation activities.
1) ”Autonomous driving on intelligent road at Europe’s edge,” ESA / Applications / Navigation, 19 January 2021, URL: https://www.esa.int/Applications/Navigation/Autonomous_driving_on_intelligent_road_at_Europe_s_edge
2) Ilkka Kotilainen, Chris Händel, Umar Zakir Abdul Hamid, Lasse Nykänen, Harri Santamala, Anna Schirokoff, Matti Autioniemi, Risto Öörni and Niklas Fieandt, ”Arctic Challenge project’s final report - Road transport automation in snowy and icy conditions,” Research reports of the FTIA (Finnish Transport Infrastructure Agency) 19/2019, URL: https://julkaisut.vayla.fi/pdf12/vt_2019-19_arctic_challenge_web.pdf
3) ”Lapland is the world’s best winter testing environment for automated driving and vehicles,” Lapland Business, 2020, URL: https://www.lapland.fi/business/
4) Carolyn Fortuna,”Harsh Finnish Lapland Is Setting For Autonomous Driving Testing (Video),” CleanTechnica, 9 December 2020, URL: https://cleantechnica.com/2020/12/09/
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (email@example.com).