Burge Carol J., Lind Judith H. A technique for measuring optical line of sight

Naval Weapons Center, China Lake, CA, 1977. — 44 p.This report is a companion to NWC TP 5908, Line-of-Sight Handbook. Its purpose is to explain how the data were collected and the computations made to produce the data presented in that report. The objective of this masking measurement program is to present probability of line of sight (LOS) as a function of terrain, range, and altitude. Preparation of the handbook included carrying out a literature search, to determine if the required data existed and, if it did not, if there was a proven technique that could be used to obtain it. Map studies, field studies, and models were examined. Models were rejected for use because their correlation with reality was not known. Information obtained from maps has many advantages, but also limitations--mainly that there is no good way to determine the effects of vegetation on LOS. There were some field data in existence, but information was all gathered for particular sites, with no attempt made to generalize according to types of terrain. However, the literature search did result in discovery of a technique that could be used, with some modification, to obtain desired data on LOS in the field. As a result of the lack of detailed and generalizable information, it was decided to undertake a measurement program that would describe the LOS characteristics of various types or terrain.