An apparatus for calibration of a probe that includes a magnetic position sensor and an acoustic imaging device has a rigid mechanical framework. One or more field generators, fixed to the framework, generate a magnetic field of known spatial characteristics. An acoustic target assembly includes a phantom coupled to a motion mechanism, which is arranged to move the phantom in a known orbit relative to the framework. A jig, fixed to the framework, holds the probe within the magnetic field of the one or more field generators, in an orientation suitable for the imaging device to image the phantom. A processor processes position and image signals from the probe in order to calibrate coordinates of the imaging device relative to the position sensor.