A method for electromagnetic navigation registration is provided. The methodincludes storing, in a memory, a mapping that associates electromagnetic field-based signalvalues with corresponding locations within a three-dimensional model of aluminal network.An ultrasound signal is received from an ultrasound probe. Based on theultrasound signal, anultrasound-based location of a target in a patient relative to the three-dimensional model isdetermined. At least a portion of the mapping is updated based on theultrasound-basedlocation of the target.
