System and method for determining at least one parameter of at least one rotating unit using an absolute position signal

The system has an activation device (7) connected to a sensor (6) and detection device (4) of parameter issued from transponder (3) mounted on a valve of a tire. The activation device activates the detection device, according to an absolute position of coder (5), when angular position of the transponder is in transmission/reception cone of directional antenna of the detection device. The antenna is housed in a passage of a wheel. Independent claims are also included for the following: (A) a method of determination of a parameter of a rotating body (B) a motor vehicle comprising a system for determining a parameter of a rotating body with respect to a fixed structure.