The Avian Infrasound Active Non-lethal Denial System was conceptualized for collision avoidance between birds and aircrafts during daily flight operations without impacting mission requirements and for preventing other forms of damage caused by birds nesting and perching in critical areas around aircrafts and other high value systems. The infrasound frequency range necessary to effectively repel birds does not interfere with any current operational aircraft or ground-based sensor systems and does not target personnel or cause injury to target birds. Preliminary tests demonstrated the technical feasibility of the system. The system is commercially viable at commercial aviation facilities, communication towers, energy wind-driven windmills that have high concentrations of birds, marine docks and harbors, etc.
Considering the development of a non-lethal avian active denial system using directed energy, the feasibility of using infrasound to repel birds in critical areas around aircraft and other high value systems was examined in a nine-month first phase Small Business Innovation Research Program (SBIR) program. A rotary woofer was used as an infrasound generator in several indoor and outdoor tests to examine the impact on birds of signals that mimic natural atmospheric infrasounds. Another test was also performed using industrial blowers in a limited natural bird habitat.
The major objectives were to provide a conceptual design of the avian active denial system, conduct a detailed analysis of the predicted performance, estimate the feasibility of infrasound in deterrence of birds and detail a plan for field testing. All objectives were successfully met.
Promising results were obtained from the preliminary tests of the reaction of birds to particular infrasonic signals. The results demonstrated the feasibility of deterring birds by producing infrasonic signals that would jam the birds’ acoustic navigational system and intermittent infrasonic signals that mimic the atmospheric disruptive features of unstable weather conditions that birds instinctively avoid, due to the workings of their innate navigational system.
Using techniques to frighten and scare birds can cause erratic behavior and chaotic conditions that may lead to aircraft damage and fatal injuries to birds. Accordingly, repelling birds in critical areas is safely achieved by broadcasting avian denial infrasonic signals, in addition to creating active bird-free zones by using interference constructive infrasound patterns around critical areas in the airfields together with low frequency noise cancelation at the perimeters of the active zones. In addition, interference destructive infrasound patterns can be used to create dead zones away from critical areas to attract birds away from airfields. Wild life sanctuaries may be established in the dead zones to navigate birds away from critical assets or divert the navigation path of the leader of a flock of migrating birds and court them away from critical areas around aircraft and other high value systems and lead them to the sanctuary; a strategy that is much safer to the assets, facilities and the birds.
Continuous and intermittent infrasound denial systems can be used alone or in conjunction with other deterrent techniques and can work in consort with a Doppler radar that detects birds’ presence within the vicinity of airstrips and runways.
After conducting further field tests in a small airport or similar environment and demonstrating the creation of active and dead zones, a working prototype system can be developed and demonstrated in actual environment.