Patent ID: 9573275
Date: 2017-02-21
CPC Classifications: A01D,B25J,G05D,Y10S

Claim:
1. A robotic work tool system, comprising a robotic work tool, said robotic work tool comprising a controller being configured to cause said robotic work tool to operate in a first operating mode, wherein the first operating mode is based on a current position, said current position being determined based on received signals that are received from a position determining device; determine that said received signals are not reliable, and in response thereto cause said robotic work tool to operate according to a second operating mode, wherein the second operating mode is not based on a current position being determined based on said received signals; and determine if a counter is lower than a threshold value when the received signals are reliable again and if so, cause the robotic work tool to execute a turn to re-enter a section where the received signals are not reliably received and increase the counter, wherein the controller is further configured to determine that the received signals are reliable again, and in response thereto switch to said first operating mode.