AGIVIS 2000 Transmissometer IRVR System Technical Description
8Pages

Aeronautical & General Instruments Limited Fleets Point Willis Way Poole Dorset BH153SS England Tel: 01202 685661

Introduction Runway Visual Range (RVR) is defined by the International Civil Aviation Organisation (ICAO) as: “The distance over which the pilot of an aircraft on the centreline of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line.” Because it is not possible to measure RVR directly, an assessment is made, either by a human observer or using an automated system to provide what is called instrumented runway visual range, IRVR....

AGIVIS 2000 _________________________________________________________________ The AGIVIS 2000 system uses a reflecting transmissometer, which means that the light beam is returned by a reflector back to the initial field site. This serves to double the baseline length along which the measurements are taken, increasing the system accuracy. The AGIVIS 2000 baseline length is 20m. The system self-­‐corrects to eliminate common causes of inaccuracy including ambient light, internal reflections, light source ...

AGIVIS 2000 _________________________________________________________________ IRVR calculations are usually carried out using a rolling 10 minute mean of extinction coefficient. However, the system is capable of recognising what is called a ‘marked discontinuity’ in visibility. This is defined by the WMO as: “…an abrupt and sustained change in runway visual range, lasting at least 2 minutes, which reaches or passes through criteria for the issuance of SPECI reports…” If a marked continuity is detected...

FILTER CLAMP FILTER FILTER TRAY CUT-AWAY TO SHOW FILTER & CLAMP FIXING PLATE PART CONCRETE BASE CABLE DUCTING Reflector Field Site Rack Equipment IRVR data from each field site is reported to other system equipment, usually mounted in a 19” rack positioned in the ATC tower. The necessary data links can be wired, fibre optic or wireless. The receiving modems and other system inputs are all mounted on the same rack. Field site IRVR data is fed to the disseminator, which acts as an internal communication node for ...

AGIVIS 2000 _________________________________________________________________ Also mounted in the rack is the Control and Recording Unit (CRU). This provides the interface to the system via a command console. Through this console raw IRVR data may be viewed, as well as the health and status of the system. It is also used to configure the system. The CRU also has an IRVR display with a similar layout as that provided to ATC personnel. It also stores data records internally, as well...

AGIVIS 2000 _________________________________________________________________ The system also complies with a number of national standards issued locally by countries worldwide, including: UK CAA CAP 746 (Meteorological Observations at Aerodromes) UK CAA CAP 670 (Air Traffic Services Safety Requirements) Installation and Support AGI offers a full installation service, which includes comprehensive site acceptance testing to demonstrate full functionality of the system. Factory-­‐based and on-­‐site training is...

AGIVIS 2000 _________________________________________________________________ IRVR Displays Operating Temperature Relative Humidity Power Requirements -­‐10°C to +40°C 95% non-­‐condensing 12V DC (an in-­‐line 90V to 264V, 50Hz to 60Hz AC PSU can be supplied) AGI is dedicated to the continuous improvement of its products. If specific requirements exist that are not covered by this Technical Description, we are always happy to discuss developments that would allow them to be fulfilled.