Catheter with distal tilt detection

Medical apparatus includes a probe including a distal part adapted for insertion into a body of a living subject and first and second magnetic transducers in the distal part of the probe. Control circuitry drives the first magnetic transducer to generate a first AC magnetic field at a first frequency and drives a magnetic field generator in proximity to the body to generate a second AC magnetic field within the body at a second frequency, calculates a disposition of the distal part of the probe by processing a first signal output by the second magnetic transducer at the first frequency, and calculates position coordinates of the distal part of the probe by processing a component of a second signal output by one of the first and second magnetic transducers at the second frequency while canceling from the second signal interference at the first frequency.