BEAM STEERING UNIT REAL TIME ANGULAR MONITOR

DOCKET R4386.01 BEAM STEERING UNIT REAL TIME ANGULAR MONITOR Proper operation of a beam steering unit for a phased array antenna, is verified by simulating the pattern of wave energy which would be radiated to an observation point in space when the beam steering unit is connected to phase shifters associated with elements of the antenia. The simulated pattern thus obtained may be compared with a preset pattern for the observation point during a scanning operation of the beam steering unit, and an alarm or other indication is obtained when the difference between the simulated and the preset pattern exceeds a certain limit. The simulated pattern is obtained by storing phase angle data from the beam steering unit in a memory at areas corresponding to phase shifters associated with elements of the phased array antenna. The memory areas are incremented from initial phase angle data corresponding to the beginning of a scan operation, in accordance with phase angle data provided by the beam steering unit at certain time intervals. Observation angle data corresponding to the angle of the point in space relative to the antenna array is generated, the observation angle data being a function of observation angle, antenna element spacing and radiation wavelength. The updated phase angle data is combined at each time interval with the observation angle data, and composite angle data is produced as a function of the combined data. From the composite angle data for each time interval, is subtracted the composite angle data for the immediately preceding time interval, and the resulting differences are accumulated with initial value composite angle data to produce a running accumulation of composite angle data in real time. The relative amplitude of wave energy which would be observed at the point in space during a scanning operation of the beam steering unit is then determined as a function of the accumulated composite angle data in real time.