Abstract: A node transmits/receives signals over first and second communication channels having non-equal propagation speeds. When node identifies reset signal received over first communication channel, it adjusts internal clock, transmits acknowledgement signal and initiates acknowledgement process. When reset signal not identified, node transmits reset signal over first communication channel and receives response signal from one node. If response signal is acknowledgement signal, acknowledgement process is initiated. If response signal is non-acknowledgement signal, internal clock is adjusted and acknowledgement process is initiated. In acknowledgement process, node determines distance to other nodes by measuring travelling time for signal over second communication channel exchanges distance information with other nodes, and fine tunes internal clock of each node when transmitting over first communication channel.

Abstract: The present invention relates to a node for use in a sensor network, e.g. for use in radar systems, using the antenna elements in each separate node as antenna elements in an array antenna configuration. The node transmits and receives signals over a first and a second communication channel having non-equal speeds of propagation. When the node identifies that a reset signal has been received over the first communication channel (S10), it adjusts the internal clock (S11), transmits an acknowledgement signal (S12) and initiates an acknowledgement process (S17). When the reset signal has not been identified, the node transmits the reset signal over the first communication channel (S13) and receives a response signal from one node (S14). If the response signal is an acknowledgement signal, an acknowledgement process is initiated (S17), or if the response signal is a non-acknowledgement signal, the internal clock is adjusted (S16) and an acknowledgement process is initiated (S17).