A method of navigating and positioning an endovascular device in a vasculature is disclosed. Initially, a system including an endovascular device and at least one transducer is inserted into the lumen of a patient. An acoustic signal is then transmitted within the lumen. A reflected signal is pre-processed to extract one or more acoustic features. The one or more acoustic features are processed using a computer readable set of rules to produce an output related to guidance of the instrument within a blood vessel or a position of the instrument within the blood vessel.