Patent EP-2549286-A1 (EP)
Inventor: GOTTIFREDI FRANCO
IPC: G01S5/02
Filed: 2012-07-18
Abstract: The present invention concerns a navigation system for exploring and/or monitoring unknown and/or difficult environments, comprising: a mission control module (11) designed for being placed in an unknown and/or difficult environment and for controlling an exploration and/or monitoring mission of said unknown and/or difficult environment; an unmanned vehicle (12) operable for carrying out the exploration and/or monitoring mission of said unknown and/or difficult environment; a primary node coupled to the mission control module (11) and comprising a respective ultra-wideband radio interface; and a plurality of secondary nodes (13) designed for being deployed in said unknown and/or difficult environment, each secondary node (13) including a respective ultra-wideband radio interface. The primary node and the secondary nodes (13) are configured to form a hierarchical communication and localization network in which: the primary node is associated with a primary hierarchical level and each secondary node (13) is associated with a respective secondary hierarchical level lower than the primary hierarchical level; each node is configured to send and receive messages over the hierarchical communication and localization network using the respective ultra-wideband radio interface; each secondary node (13) is configured to carry out, using the respective ultra-wideband radio interface, distance measurements with respect to, and together with, other secondary nodes (13) associated with the same secondary hierarchical level with which said secondary node (13) is associated, and with respect to, and together with, other nodes associated with hierarchical levels adjacent to the secondary hierarchical level with which said secondary node (13) is associated, and to send to the primary node distance-related messages concerning the distance measurements carried out by said secondary node (13) and integrity-related messages indicating a respective state of operational integrity of said secondary node (13); and the primary node is configured to carry out, using the respective ultra-wideband radio interface, distance measurements with respect to, and together with, secondary nodes (13) associated with a secondary hierarchical level immediately lower than the primary hierarchical level, to compute, on the basis of the distance measurements carried out by said primary node and the distance-related messages received from the secondary nodes (13), a local reference coordinate system indicative of the positions of the secondary nodes (13) with respect to the primary node, and to determine an overall integrity state of the hierarchical communication and localization network on the basis of the integrity-related messages received from the secondary nodes (13), the distance measurements carried out by said primary node and the distance-related messages received from the secondary nodes (13), said overall integrity state of the hierarchical communication and localization network being indicative of the states of operational integrity of the secondary nodes (13) and of levels of reliability and accuracy of the positions of the secondary nodes (13) in the local reference coordinate system. The unmanned vehicle (12) comprises a vehicle control unit that includes a respective predefined radiocommunication interface and a respective ultra-wideband radio interface and that is configured to receive data from the mission control module (11) using the respective predefined radiocommunication interface. The mission control module (11) comprises a respective predefined radiocommunication interface and is configured to send mission data regarding the exploration and/or monitoring mission and navigation data regarding the local reference coordinate system and the overall integrity state of the hierarchical communication and localization network to the vehicle control unit using the respective predefined radiocommunication interface. The vehicle control unit is further configured to: carry out, using the respective ultra-wideband radio interface, distance measurements with respect to, and together with, one or more nodes of the hierarchical communication and localization network; compute a position of the unmanned vehicle (12) in the local reference coordinate system on the basis of navigation data received from the mission control module (11) and the distance measurements carried out by said vehicle control unit; and pilot the unmanned vehicle (12) in said unknown and/or difficult environment on the basis of mission data and the navigation data received from the mission control module (11), the distance measurements carried out by said vehicle control unit and the position of the unmanned vehicle (12) in the local reference coordinate system.