1. A system for stereotactic positioning in real time of a first object or part thereof relative to a second object or part thereof, the system comprising: a. at least three transmitting units (TUs) arranged spatially such that no more than three TUs are coplanar, each TU comprising at least one ultrasound (US) transmitter, at least one radio frequency (RF) transmitter and at least one TU clock, wherein at least one TU includes two US transmitters configured to transmit on two different frequencies, respectively; b. a mobile unit (MU) fixedly coupled to the first object, the MU comprising at least one MU clock, at least one RF transmitter/receiver and at least two US receivers spaced apart and positioned in a predetermined geometrical relation relative to the first object or part thereof and to one another; c. at least one storage unit for storing scanned images of the second object; and d. a central processing unit (CPU) configured to: (1) receive data from the US and RF receivers from said MU; (2) receive imaging data from said storage unit, said imaging data comprising at least one scanned image of the second object with at least three image markers indicated over the at least one image of the second object; (3) identify positions of at least three real markers over the second object in real space; (4) determine a real space position and inclination of said first object or part thereof based on time-of-flight (TOF) data obtained from combined US transmissions between said US transmitters of the TUs and said US receivers at the MU and RF transmissions between said RF transmitters in said TUs and said RF receiver in said MU using said TUs and MU clocks; (5) determine real space positioning and inclination of the first object or part thereof relative to real space location of the second object or part thereof, based on locations of the at least three real markers in real space and the at least three image markers in the imaging data; (6) reconstruct, in real time, an image of the second object or part thereof with an indication of the first object or part thereof based on real time and real space positioning and inclination of the first object or part thereof in respect to the position of the second object or part thereof; and (7) display said reconstructed image.