Abstract: A transportable ground tower for an aircraft landing system, and methods of assembling and raising the same, are disclosed. The ground tower may include at least lower and upper tower sections configured to be assembled to form a ground tower structure extending substantially vertically from a ground surface in an operational orientation. The lower tower section may have a pivot configured to be pivotally secured to a stationary ground base. The ground tower may also include a stand pivotably secured to one of the plurality of tower sections, which is configured to support an end of the assembled tower structure in an assembly orientation to permit assembly of one or more tower devices to the tower structure.

Abstract: A ground-based, precision aircraft landing system provides CAT I precision approach and landing guidance. The aircraft elevation position is determined by measuring differential carrier phase and time-of-arrival of the aircraft ATCRBS transponder reply. The transponder reply is received at a plurality of sensor antenna locations where it is then conveyed to a sensor, demodulated and digitized. The data is transmitted to a central processor where calibration and multipath corrections are applied. Aircraft transponder diversity antenna switching is isolated from the jitter and colored noise of transponder reply multipath by correlating differential phase jumps measured between separate sensor antennas. An estimate of the diversity antenna separation is maintained by Kalman filter processing; the estimated separation is used to correct the differential phase measurement data of aircraft elevation.