Otis ANGB (Air National Guard Base) Visibility Sensor Field Test Study.
Abstract
This study is part of a continuing effort to evaluate forward scatter meters (FSMs) for use as visibility sensors in Automatic Observing Systems (AOS) and as possible replacements for transmissometers to measure Runway Visual Range (RVR) at airports. The report analyzes data collected from three FSMs at the Otis Air National Guard Base during a 17-month period starting in 1983. Two of the FSMs use chopped incandescent light sources and have a large scatter volume. The other uses a modulated light emitting diode (LED) light source and has a small scatter volume. Two analysis procedures are included: 1) a statistical analysis of the entire data set disaggregated according to the obstruction to vision (fog, rain, snow, etc.) and the magnitude of the extinction coefficient; and 2) detailed analysis of selected reduced visibility events. Most of the time extinction coefficients measured by the FSMs and the transmissometers agreed to within 16.5 percent for RVR values between 400 and 6000 feet and within one reporting increment for AOS visibility. Most of the cases of large disagreement were traced to problems such as sensors being clogged by snow, which affected both FSMs and the transmissometers. In terms of operational utility, the large volume FSMs gave more stable readings, but the FSM with the LED light source exhibited less calibration drift and greater reliability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1987
- Accession Number
- ADA179176
Entities
People
- D. Burnham
- Daniel Schwartz
Organizations
- John A. Volpe National Transportation Systems Center