AbstractTheTimeReferenceScanningBeam(TRSB) landing system is an air‐derived data system which operates at microwave frequencies to provide guidance information proportional to an aircraft's lateral and vertical displacement from a selected flight profile. Angular position of an aircraft is measured in the aircraft by receiving ground generated fan beams which scan “to” and “fro” across the coverage sector in both azimuth and elevation. The airborne subsystem measures the elapsed time between a given “to”‐“fro” scan. The time difference is controlled to be an indication of the aircraft's angular position. This indicated angle could be corrupted by multipath. Basic to the TRSB concept is the azimuth and elevation controlled antenna radiation patterns (both in the scan and non‐scan dimensions) which, in conjunction with their high scan rates, control the multipath to an operationally acceptable level. Since the multipath is controlled primarily on the ground, there is no special impact on the cost of the airborne equipment because simple, conventional RF and signal processing techniques need only be implemented into the airbo