Abstract: In accordance with the present invention there is provided a monitoring system that monitors and locates objects such as airplanes and other vehicles on runways, taxiways, or other preprogrammed areas. The invention utilizes a minimum of three transmitters for generating a diffusion field and two receivers which detect displacements in a diffusion field. The receivers are coupled with a computer which calculates the position of the object causing the displacement in the diffusion field. The area to be monitored is divided into grids which are programmed onto the computer, and objects moving in the monitored area cause changes in the signal received by the receivers which are conveyed to the computer and compared by the computer to the programmed grid to indicate the location of the object causing the changes.