A method for universal beacon code allocation

Beacon codes or squawk codes are a set of limited National Airspace System (NAS) resource. The Air Traffic Control Radar Beacon System (ATCRS) was deployed for civilian use by FAA after World War II. With the increase in demand for codes resulting from the growth in air traffic, the current system of beacon code allocation leads to code reassignments which are inefficient. Also, the current system is vulnerable to code shortages as the traffic grows. This paper describes a new algorithm of beacon code assignment that eliminates the need for “reassignment” and is also more scalable to increasing traffic in the NAS. The method, Space-Time Adjacency (STA) algorithm, assigns unique codes to flights by exploiting the temporal and spatial opportunities in individual flightplans. Five high traffic volume days across different seasons of 2007 were used to test the algorithm performance and robustness. The results show that this method of code assignment required zero reassignments.