An apparatus (111,112,121) for reducing collision risks between an entity (161,162) and at least an obstacle (161,162,171), comprising - transmitting means adapted to emit a first beacon signal (131,132,133, - receiving means adapted to receive at least a second beacon signal (131,132,133) that can be emitted by another apparatus (111,112,121) which could dangerously approach to said apparatus, - processing means in signal communication with said transmitting and receiving means (201,202), characterised in that said processing means is configured for - detecting at least said second beacon signal (131,132,133) received through the receiving means, - detecting at least a first property and a second property of at least said second beacon signal (131,132,133), - setting, on the basis of said at least first property and second property of said second beacon signal, at least a first property and a second property of the first beacon signal (131,132,133), - emitting said first beacon signal through the transmitting means,wherein said first property of said first beacon signal comprises first timing information defining the timing of said first beacon signal, and said first property of said second beacon signal comprises second timing information defining the timing of the second beacon signal, and - -determining, on the basis of said second timing information, the first timing information so that the first and second beacon signals (131,132,133) do not overlap, wherein said second property of said first beacon signal comprises first channel information defining a first sequence of communication bands in which the first beacon signal will be emitted, and said second property of said second beacon signal comprises second channel information defining a second sequence of communication bands on which the second beacon signal has been received. - transmitting means adapted to emit a first beacon signal (131,132,133, - receiving means adapted to receive at least a second beacon signal (131,132,133) that can be emitted by another apparatus (111,112,121) which could dangerously approach to said apparatus, - processing means in signal communication with said transmitting and receiving means (201,202), - detecting at least said second beacon signal (131,132,133) received through the receiving means, - detecting at least a first property and a second property of at least said second beacon signal (131,132,133), - setting, on the basis of said at least first property and second property of said second beacon signal, at least a first property and a second property of the first beacon signal (131,132,133), - emitting said first beacon signal through the transmitting means,wherein said first property of said first beacon signal comprises first timing information defining the timing of said first beacon signal, and said first property of said second beacon signal comprises second timing information defining the timing of the second beacon signal, and - -determining, on the basis of said second timing information, the first timing information so that the first and second beacon signals (131,132,133) do not overlap, wherein said second property of said first beacon signal comprises first channel information defining a first sequence of communication bands in which the first beacon signal will be emitted, and said second property of said second beacon signal comprises second channel information defining a second sequence of communication bands on which the second beacon signal has been received.