operate application_number US 64033706 A description in the following detailed description reference is made to the accompanying drawings which form a part hereof and show by way of illustration specific embodiments in which the invention may be practiced these embodiments are described in sufficient detail to enable those skilled in the art to practice the invention and it is to be understood that other embodiments may be utilized and that structural logical and other changes may be made without departing from the spirit and scope of the present invention the progression of processing steps described is exemplary of embodiments of the invention however the sequence of steps is not limited to that set forth herein and may be changed as known in the art with the exception of steps necessarily occurring in a certain order an exemplary positioning system 10 is shown in fig1 the positioning system has transmitter sites 12 and a receiver unit 14 as shown in fig1 the positioning system 10 entails the design and integration of a number of components the first components are surface magnetic beacons 12 that provide a continuous signal on different frequencies in the very low low frequency range three to four 3 4 of these transmitters beacons 12 are usually required to support the positioning system 10 in the system.