The base for on-board navigation is a local DEM which is used by path planning in terms of traversability, possible hazards, locomotion costs, reliability and information content. Terrain modelling can be performed by a laser scanner, laser illuminated cameras, radio-frequency (RF) imagers or stereovision cameras which appear the best compromise for reliability and accuracy on one side and mass, power consumption and space qualification readiness on the other.
Within the PRoViScout project a 3D-TOF camera is used for this purpose. DEM resolution should be much better than a wheel rover size to allow terrain crossing analysis.
Rover Autonomous Navigation has been studied in many Robotics research laboratories among which CMU and Caltech in the USA, and LAAS in France have produced well known results. However, only few studies have been carried out to develop software able to run on a planetary rover, due to resource and processing constraints.
For the more recent planetary missions, the on-board computing capabilities allow more sophisticated strategies yielding to the autonomy of the navigation software in a daily traverse basis. Terrain modelling and labelling as well as path planning and path execution are performed on-board, without need of the Ground Control Centre intervention, and should provide target reaching capacity.
The current solution implemented in the Eurobot Ground Prototype follows this methodology. This project was awarded by the European Space Agency (ESA) to an industrial consortium lead by Thales Alenia Space Italia. Within this project, GMV was responsible of the development of the mobile platform “EGP-Rover” with Technical University of Zurich (ETHZ) and Joanneum Research (JR) from Austria as subcontractors.
The goal of the EGP-rover is to achieve a highly-accurate mobile system (1.5m x 1m), equipped with two robot arms, either for short distance mobility in the lander vicinity or to transport an astronaut and/or another payload (up to 400 Kg) to a target location, trespassing unknown terrain.
The EGP-Rover supports various operational modes, such as autonomous navigation, joystick driving, remote commanding, finding & following a moving Astronaut, or finding a specific location on the ground where the Astronaut is pointing using a special light pointing device.
Autonomous navigation capabilities are based on the path planning algorithms that are able to compute the shortest free-of-obstacles path and then a sense-plan-act loop able to navigate from origin location to target destination. From a path planning point of view the optimal route between two points separated a long-range generally is to be performed in several iterations. In each of this iteration, the Guidance, navigation and control (GNC) determines the optimal route supposing that the unknown area do not have obstacles (we might have some limited information regarding big obstacles observed from orbit-based cartography or from images taken during the landing by the lander cameras).
GMV AEROSPACE AND DEFENSE S.A. (GMV) is a Spanish privately owned company devoted to consultancy, engineering, software development and turn-key systems integration for the aerospace and defence sector. Integrated within GMV Innovarting Solutions, today Grupo GMV employs more than 1000 staff, most of whom work in the Space business (about 400) and have outstanding experience and capabilities. It generates about 62% of the group’s total turnover (77 millions Euros in 2007).
Founded in 1984, GMV mainly operates in nine large sectors for both public and private organisations: Aeronautics, space, defence, health, security, transportation, telecommunications and information technologies. GMV provides system integration, operations support, information technology (IT) consulting and engineering services, hardware and software development, and technologically solutions. It offers mission analysis, satellite control and scientific operations centers, flight dynamics, systems engineering and GNC, mission planning, payload segment, user segment and space applications, simulation, navigation systems, on-board software, and related ITC solutions for space industry; and systems and software, experimental system and equipment, flight test platform integration, navigation systems, GNSS infrastructure, air traffic management support systems, simulators, test benches, and aeronautics telecommunications solutions for aeronautics industry. The company also offers architectures based on TIBCO technology and security operations center solutions for banking and insurance industry; corporate portal and data storage systems, as well as vertical portal incorporating sections of electronic commerce, online travel management, and leisure and mini-site solutions for business ITC; and space military applications, on-board equipment, avionics software, test benches, data and signal processing, intelligence systems, simulation, C3I systems, engineering and security systems, and related ICT solutions for defense and security industry.
GMV will adapt their EUROBOT Rover GNC system to the PRoViScout project, including an operational interface to the locomotion system of the AU Rover.
More information about GMV can be found at corporate web site www.gmv.com.