A controller (120) for simultaneously tracking multiple sensors in a medical intervention includes a circuit (121-181) that causes the controller (120) to execute a process. The process executed by the circuit (121-181) includes receiving first and second signals respectively from a first and a second passive ultrasound sensor (S2) used in the medical intervention. The first and second signals respectively include first and second sensor information indicative of respective locations of the first and the second passive ultrasound sensor (S2). The process executed by the circuit (121-181) also includes combining (120) the first signal and the second signal for transmission over only one channel, and providing the first signal and the second signal over the only one channel to a system (190) that determines the location of the first passive ultrasound sensor (S1) and the location of the second passive ultrasound sensor (S2) and that has only the one channel to receive the first signal and the second signal.