One of the main reasons why ADS-B (Automatic Dependant Surveillance — Broadcast) has not been accepted as main source of surveillance information for Air Traffic Control (ATC) systems is its relative vulnerability against false target position reports. To remediate the issue, today's systems usually have independent surveillance system verifying the correctness of the ADS-B messages. This will make the overall air surveillance system complex and expensive. A thorough overview about the ADS-B security issues and possible realistic solutions are given in [1]. We will propose an alternative solution based on two dimensional beamforming algorithm. It will be based on Robust Generalized Sidelobe Canceller which uses Slepian sequences to address this problem. Potential other applications of proposed algorithm is Massive MIMO or any other communication system that needs simultaneous data transmission between spatially segregated nodes.