A positioning or navigation system for positioning and navigating an endovascular instrument in a vasculature, comprising: an acoustic transducer and an ECG electrode for mounting on a distal end of the endovascular instrument; a control system in communication with the acoustic transducer and the ECG electrode, the control system being configured to generate and receive an acoustic signal using the acoustic transducer and to receive an ECG signal using the ECG electrode; a pre-processor configured to receive the acoustic signal as an acoustic input and to receive the ECG signal as an ECG input, the pre-processor containing computer-readable instructions for manipulating the acoustic input and the ECG input to extract one or more acoustic features from the acoustic input and one or more ECG features from the ECG input; a processor configured to receive the one or more extracted acoustic features and the one or more extracted ECG features, the processor containing a computer-readable set of rules to: input the extracted acoustic features and the extracted ECG features into one or more predefined membership functions indicative of positional or navigational state of the endovascular instrument; generate a score for each one or more positional or navigational states, wherein each score is based on a predetermined subset of the one or more predefined membership functions, wherein each score indicates a likelihood that the endovascular instrument is in the corresponding positional or navigational state; compare the generated scores to determine the positional or navigational state of the endovascular instrument; generate positional or navigational guidance information for the endovascular instrument based on the determined positional or navigational state; and an output device for displaying the positional or navigational guidance information generated by the processor. an acoustic transducer and an ECG electrode for mounting on a distal end of the endovascular instrument; a control system in communication with the acoustic transducer and the ECG electrode, the control system being configured to generate and receive an acoustic signal using the acoustic transducer and to receive an ECG signal using the ECG electrode; a pre-processor configured to receive the acoustic signal as an acoustic input and to receive the ECG signal as an ECG input, the pre-processor containing computer-readable instructions for manipulating the acoustic input and the ECG input to extract one or more acoustic features from the acoustic input and one or more ECG features from the ECG input; a processor configured to receive the one or more extracted acoustic features and the one or more extracted ECG features, the processor containing a computer-readable set of rules to: input the extracted acoustic features and the extracted ECG features into one or more predefined membership functions indicative of positional or navigational state of the endovascular instrument; generate a score for each one or more positional or navigational states, wherein each score is based on a predetermined subset of the one or more predefined membership functions, wherein each score indicates a likelihood that the endovascular instrument is in the corresponding positional or navigational state; compare the generated scores to determine the positional or navigational state of the endovascular instrument; generate positional or navigational guidance information for the endovascular instrument based on the determined positional or navigational state; and an output device for displaying the positional or navigational guidance information generated by the processor. input the extracted acoustic features and the extracted ECG features into one or more predefined membership functions indicative of positional or navigational state of the endovascular instrument; generate a score for each one or more positional or navigational states, wherein each score is based on a predetermined subset of the one or more predefined membership functions, wherein each score indicates a likelihood that the endovascular instrument is in the corresponding positional or navigational state; compare the generated scores to determine the positional or navigational state of the endovascular instrument; generate positional or navigational guidance information for the endovascular instrument based on the determined positional or navigational state; and an output device for displaying the positional or navigational guidance information generated by the processor.