Author Description

A forward scattermeter, consisting of transmitter and receiver heads mounted on a fork, is used in the New Generation Runway Visual Range (NGRVR) System to assess the clarity of the atmosphere. The scatter meter is calibrated by comparison with reference transmissometers. The consistency of the calibration from one unit to the next is verified by measuring the fork geometry and using a performance model to predict the expected calibration variation for different forks. The model also assesses the possible effects of head variations. The variations in fork geometry through the 650-unit production run are presented. The additional steps needed to complete the calibration validation are defined.