System for determining a position of an interventional device respective an image plane defined by an ultrasound imaging probe of a beamforming ultrasound imaging system in which the position of the interventional device is determined based on ultrasound signals transmitted between the ultrasound imaging probe and an ultrasound transducer attached to the interventional device, the system comprising: an image reconstruction unit configured to provide a reconstructed ultrasound image corresponding to an image plane defined by the ultrasound imaging probe; a position determination unit configured to: compute a position (LAP TOFSmax, θIPA) of the ultrasound transducer respective the image plane based on a time of flight (TOFsmax) of a maximum detected intensity (I Smax) ultrasound signal transmitted between the ultrasound imaging probe and the ultrasound transducer; and to indicate the computed position (LAP TOFSmax, θIPA) in the reconstructed ultrasound image; and characterised in that the position determination unit is further configured to suppress the indication of the computed position (LAP TOFSmax, θIPA) if at least one of the following conditions are met: a rate of change of the computed position (LA-P TOFSmax, θIPA) exceeds a first predetermined rate (R Max1); an interference signal in the ultrasound signals exceeds a first predetermined value (Int Threshold1). an image reconstruction unit configured to provide a reconstructed ultrasound image corresponding to an image plane defined by the ultrasound imaging probe; a position determination unit configured to: compute a position (LAP TOFSmax, θIPA) of the ultrasound transducer respective the image plane based on a time of flight (TOFsmax) of a maximum detected intensity (I Smax) ultrasound signal transmitted between the ultrasound imaging probe and the ultrasound transducer; and to indicate the computed position (LAP TOFSmax, θIPA) in the reconstructed ultrasound image; and characterised in that the position determination unit is further configured to suppress the indication of the computed position (LAP TOFSmax, θIPA) if at least one of the following conditions are met: a rate of change of the computed position (LA-P TOFSmax, θIPA) exceeds a first predetermined rate (R Max1); an interference signal in the ultrasound signals exceeds a first predetermined value (Int Threshold1). compute a position (LAP TOFSmax, θIPA) of the ultrasound transducer respective the image plane based on a time of flight (TOFsmax) of a maximum detected intensity (I Smax) ultrasound signal transmitted between the ultrasound imaging probe and the ultrasound transducer; and to indicate the computed position (LAP TOFSmax, θIPA) in the reconstructed ultrasound image; and characterised in that the position determination unit is further configured to suppress the indication of the computed position (LAP TOFSmax, θIPA) if at least one of the following conditions are met: a rate of change of the computed position (LA-P TOFSmax, θIPA) exceeds a first predetermined rate (R Max1); an interference signal in the ultrasound signals exceeds a first predetermined value (Int Threshold1). a rate of change of the computed position (LA-P TOFSmax, θIPA) exceeds a first predetermined rate (R Max1); an interference signal in the ultrasound signals exceeds a first predetermined value (Int Threshold1).