ACSA King Shaka International Airport Bird Detection Radar System
Mount Moreland Barn Swallows 


Barn Swallow Radar

Radar has been used for detecting and monitoring bird movements for over 60 years, however application of dedicated bird detection radars for managing aircraft birdstrike hazards at airfields and airports has only undergone serious development focus over the past two decades, primarily driven by needs of the military and advances in computer technology. The U.S. Air Force (USAF) has been a leader in development of radar remote sensing systems for bird detection and avoidance, supporting numerous significant projects to advance the level of the technology. 


Dedicated bird detection radar systems today typically consist of multiple radar sensors, some with ancillary equipment and features for enhanced functionality and automation. The most frequently used radar is a wide array antenna which is preferred due to its lower cost, broad beam detection coverage, ease of use, and robust, proven reliability. The most advanced systems on the market use dual scanning radar sensors consisting of a vertical scanning radar (VSR) and a horizontal surveillance radar (HSR).  The actual radar antennas are commercial off the shelf products used primarily by the maritime industry and are mounted on most large ocean liners. 


The VSR operates in the X-band frequency, scanning horizon-to-horizon through the vertical plane with the radar aligned with the runway to provide coverage of the runway approach and departure corridors. In the vertical scanning orientation, the radar is turned on its side so that it scans a vertical slice through the atmosphere detecting hazardous bird activity in on and above the runway and in the critical runway corridors from the ground level to aircraft operational altitudes. The VSR radar sends out a fan-shaped beamBarn swallow bird detection radar and, depending on power, can reliably detect bird targets up to 3-4 nautical miles (nm) to either side of the radar and to 15,000 feet (ft) above the runway. The HSR operates in the S-band frequency concurrently with the VSR, scanning 360 degrees around the airfield detecting and tracking bird activity from the ground level to aircraft out to 6-8 nm. 


The combined vertical and horizontal scanning configuration in MERLIN provides the maximum level of coverage in a cost effective manner with specific, dedicated 3D coverage for the runways and approach and departure corridors where 85% of airfield and airport bird strikes occur. 

Barn Swallow RadarCombined, the HSR and VSR beams deliver optimal detection of hazardous bird activity in a cost-effective package that includes detection and tracking of birds at the lower altitudes (under 500ft) where 85% of commercial bird strikes occur. The VSR additionally provides precise altitude information that can be used by controllers to more effectively manage risk in the most critical runway approach and departure corridors and along the runway. 


The analogue radar signal gets converted to a digital format by specialised computer graphics hardware.  Custom developed radar software programs are then used to track targets (birds). 


The bird radar in use at the King Shaka International Airport is a Merlin XS2530i Aircraft Bird Avoidance Radar supplied by DeTect Inc. a USA based company that specialises in the development of proprietary bird detection radar systems for the aviation industry. 

Due to the unique nature of the Barn Swallow flocks near to KSIA DeTect developed a Swallow Detection Algorithm (SDA) that tracks the movements of the swallow flocks in the early mornings and late afternoons.Bird Detection Radar System - Merlin  The SDA also generates advisory warnings which can then be relayed directly to aircraft via the radar operator and the air traffic controller. 

During the early mornings and late afternoons high resolution data from the radar are being recorded for continued analysis of the behaviour of the barn swallows.  All the radar data collected since 2007 indicate that the airport and the Barn Swallows that roost at Mount Moreland can easily co-exist.  The time intervals during which the swallows could potentially pose a risk to aviation are short in duration and predictable.  The fact that the bird detection radar information will provide an advisory to air traffic control will ensure that pilots receive timeous information regarding the bird strike risk.  Airport operations will thus take the barn swallows into consideration ensuring a co-existence between the airport and the swallows.

This will be the first commercial airport where information from a bird detection radar will be used actively by air traffic controllers to warn pilots of current bird strike risks. 

The KSIA bird radar also tracks the movement of other bird species and provides a detailed overview report to bird and wildlife staff on a daily basis.  This further enhances the ability of the bird and wildlife department to understand bird behaviour and risks on and around the airfield and how best to align their scaring tactics. 

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