Patent ID: 8644768

Claim:
A method for distance measurement between two nodes of a radio network, the method comprising: transmitting a first unmodulated carrier signal by the first node received by the second node; transmitting a second unmodulated carrier signal by the second node received by the first node; measuring a first value and a second value of a first phase by the first node, the first value of the first phase being assigned to a first frequency of the received second carrier signal and the second value of the first phase being assigned to a second frequency of the received second carrier signal, the first frequency and the second frequency having a frequency difference; measuring a third value and a fourth value of a second phase by the second node, the third value of the second phase being assigned to a third frequency of the received first carrier signal and the fourth value of the second phase being assigned to a fourth frequency of the received first carrier signal, the third frequency and the fourth frequency having the frequency difference; and determining the distance from the frequency difference and from the first value and the second value of the first phase and from the third value and fourth value of the second phase.