This invention provides small position sensors for applications where localized sensing in a small volume of space is needed but where measurement of large relative displacement is also necessary. The invention enables a surgeon to accurately position the tip of a catheter during minimally invasive therapy. The current invention further improves the quality of tactile feedback to a physician during catheter-based surgeries with an axial force sensor at the tip of the catheter that allows for the transmission of force information to the physician. One embodiment of this invention is a position sensor for active interventional catheters, where the sensor may be laser-machined shape memory alloy (SMA), and the catheter actuators may be heated SMA or wire-pulleys. Providing position feedback from a catheter during minimally invasive therapy allows for closed-loop control of the catheter tip position under computer-aided guidance and enable force feedback to the physician.