ILS farfield alignment monitor for ILS uses opposed ILS antennas avoids many errors reduces cost

摘要

The ILS farfield alignment monitor couples (17a,b-20a,b) signals from the ILS antenna arrays (21a,b) at opposite ends of the runway and switches (30a,b) these to a processor (34a) which compares 90 and 15 Hz modulation depths to give a monitoring parameter which is compared with a reference.