By receiving a terrain clearance measuring radio (a radio altimeter) wave produced by an aircraft, aircraft noise discriminator Type-II (RD-100) can measure the point-blank passing time within 1 or 2 seconds range (industrial property). A combined use of RD-90 (Type-I) and RD-100 (Type-II) with the aircraft noise monitoring station (DL series) can realize the following functions.
- By monitoring a radio altimeter intensity level, it can detect the point-blank passing time.
- It can measure the approximate position and judge the direction of an aircraft flew toward/from.
- In the case of monitoring multiple noise events while an aircraft passes by, it can identify the aircraft noise event with reference to the point-blank passing time.
