A node for use in a sensor network together with at least one other node, each node having at least one antenna element configured to be used as an antenna element in an array antenna, wherein the node comprises: - an internal clock, - a transceiver circuitry configured to transmit and receive signals over at least a first communication channel and a second communication channel with non-equal speed of propagation, over the at least one antenna element, and a processor; wherein the node is configured to identify if a reset signal has been received over the first communication channel, and when the reset signal has been identified, the node is further configured to a) adjust the internal clock based on the reset signal, transmit an acknowledgement signal in response to the received reset signal and initiate an acknowledgement process, or when the reset signal has not been identified, the node is further configured to b) transmit the reset signal over the first communication channel and receive a response signal in response to the transmitted reset signal from at least one of the at least one other node, and b1) if the response signal is an acknowledgement signal, the node is further configured to initiate an acknowledgement process, or b2) if the response signal is a non-acknowledgement signal, the node is configured to adjust the internal clock based on the received non-acknowledgement signal and to initiate an acknowledgement process, wherein, in order to perform the acknowledgement process, the node is further configured to: c) determine a distance to the at least one other node by measuring the travelling time for a signal over the second communication channel, exchange distance information with the at least one other node, and fine tune the internal clock of each node based on the distance information when transmitting over the first communication channel. - an internal clock, - a transceiver circuitry configured to transmit and receive signals over at least a first communication channel and a second communication channel with non-equal speed of propagation, over the at least one antenna element, and a processor; wherein the node is configured to identify if a reset signal has been received over the first communication channel, and when the reset signal has been identified, the node is further configured to a) adjust the internal clock based on the reset signal, transmit an acknowledgement signal in response to the received reset signal and initiate an acknowledgement process, or when the reset signal has not been identified, the node is further configured to b) transmit the reset signal over the first communication channel and receive a response signal in response to the transmitted reset signal from at least one of the at least one other node, and b1) if the response signal is an acknowledgement signal, the node is further configured to initiate an acknowledgement process, or b2) if the response signal is a non-acknowledgement signal, the node is configured to adjust the internal clock based on the received non-acknowledgement signal and to initiate an acknowledgement process, a) adjust the internal clock based on the reset signal, transmit an acknowledgement signal in response to the received reset signal and initiate an acknowledgement process, or when the reset signal has not been identified, the node is further configured to b) transmit the reset signal over the first communication channel and receive a response signal in response to the transmitted reset signal from at least one of the at least one other node, and b1) if the response signal is an acknowledgement signal, the node is further configured to initiate an acknowledgement process, or b2) if the response signal is a non-acknowledgement signal, the node is configured to adjust the internal clock based on the received non-acknowledgement signal and to initiate an acknowledgement process, b1) if the response signal is an acknowledgement signal, the node is further configured to initiate an acknowledgement process, or b2) if the response signal is a non-acknowledgement signal, the node is configured to adjust the internal clock based on the received non-acknowledgement signal and to initiate an acknowledgement process,