A probe navigation system for use with a subject, comprising: a control system and associated probe configured to be operated to controllably insert and move a distal end of the probe to and within a walled area within the subject; wherein: the distal end of the probe includes first and second opposing transducers mounted thereon; the first transducer is configured on the probe to sense a first wall within the walled area and the second opposing transducer is configured on the probe to sense an opposing wall within the walled area; the control system is configured to track movement of the distal end of the probe towards the first wall using the first transducer and with respect to the opposing wall using the second transducer; and upon a condition that the distal end of the probe closely approaches the first wall where the first transducer is unable to properly sense the first wall, the control system is configured to use information generated by the second transducer of the movement of the probe with respect to the opposing wall to provide tracking of the distal end of the probe towards the first wall whereby contact with the first wall is determinable irrespective of the inability of the first transducer to properly sense the first wall. a control system and associated probe configured to be operated to controllably insert and move a distal end of the probe to and within a walled area within the subject; wherein: the distal end of the probe includes first and second opposing transducers mounted thereon; the first transducer is configured on the probe to sense a first wall within the walled area and the second opposing transducer is configured on the probe to sense an opposing wall within the walled area; the control system is configured to track movement of the distal end of the probe towards the first wall using the first transducer and with respect to the opposing wall using the second transducer; and upon a condition that the distal end of the probe closely approaches the first wall where the first transducer is unable to properly sense the first wall, the control system is configured to use information generated by the second transducer of the movement of the probe with respect to the opposing wall to provide tracking of the distal end of the probe towards the first wall whereby contact with the first wall is determinable irrespective of the inability of the first transducer to properly sense the first wall. the distal end of the probe includes first and second opposing transducers mounted thereon; the first transducer is configured on the probe to sense a first wall within the walled area and the second opposing transducer is configured on the probe to sense an opposing wall within the walled area; the control system is configured to track movement of the distal end of the probe towards the first wall using the first transducer and with respect to the opposing wall using the second transducer; and upon a condition that the distal end of the probe closely approaches the first wall where the first transducer is unable to properly sense the first wall, the control system is configured to use information generated by the second transducer of the movement of the probe with respect to the opposing wall to provide tracking of the distal end of the probe towards the first wall whereby contact with the first wall is determinable irrespective of the inability of the first transducer to properly sense the first wall. <EOS>