A robotic lawnmower (100) for movable operation within a work area (205) has a satellite navigation device (190), a landmark scanner (193) and a controller (110). The controller causes the robotic lawnmower (100) to movably operate within the work area (205) in a first operating mode, the first operating mode being based on positions determined from satellite signals received by the satellite navigation device (190). The controller determines that a position cannot be reliably determined based on satellite signals received by the satellite navigation device (190), and in response thereto causes the robotic lawnmower (100) to movably operate within the work area (205) in a second operating mode. In the second operating mode, the controller receives scanning information from said landmark scanner (193) and identifies at least one landmark based on the received scanning information and determines a landmark-based position estimate. The controller defines a search space using the landmark-based position estimate,
