This paper describes a system based on cognitive radio technology to improve the reliability and security of wireless communications of unmanned aerial systems and vehicles (UAS/UAV) networks. UAS/UAV networks can experience problems with connectivity and thus with data reception and delivery. Since UAS/UAV are mobile, their connectivity is dynamic; thus, link status changes are more frequent than for traditional networks. Specifically, link losses due to jamming, interference, fading, and multipath are common problems. Another factor is the way the radio spectrum is used at each specific location. The availability of specific spectrum frequency bands can vary from one location to another, thus making it crucial for aircraft to be frequency agile to maintain connectivity.
