Chapter 2 __________________________________________________________ Product Overview
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CHAPTER 2
PRODUCT OVERVIEW
This chapter gives an overview of the AviMet system and its components.
System Introduction
Vaisala AviMet® Low-Level Windshear Alert System (LLWAS) is a
ground-based low-level windshear alert system. It provides visual and
audio alerts on calculated windshear and microburst conditions for air
traffic controllers and other airport personnel.
The system measures, processes, displays, stores, and distributes
meteorological information. It consists of sensors located along the
runway, one or two central data unit computers (CDUs), and one or several
workstations.
The sensors are located along the runways at specific measurement sites
and communicate with the central data units (CDUs), which distribute the
data to the workstations. The system can be single-CDU or duplicated, that
is, it can include one or two CDUs. The CDU validates the measurement
data, calculates the values based on the data, and distributes the weather
data and alarms to user workstations.
Vaisala AviMet® Low-Level Windshear Alert System (LLWAS) consists
of wind speed and wind direction sensors located around the runway area
perimeter. The CDU processes the horizontal wind speed and direction
data using the LLWAS III algorithm, developed by NCAR for the U.S.
Federal Aviation Administration (FAA). Windshear and microburst alerts
are provided when the data generated by the system exceeds the airport-
specific threshold values for possible windshear conditions.