The vulnerability of GPS to interference has been a major concern for both military and civilian applications, including small UAVs. Various signal processing techniques have been developed to improve the reliability of GPS receivers against different types of interference. Among these techniques, null steering is recognized as an effective method to protect GPS against both narrowband and broadband interference. However, due to the requirement of multiple antenna channels, it has mainly been implemented for large platform applications. This thesis examines the suitability of null steering techniques for small UAV applications and determines the practically achievable anti-jamming ability by implementing a two-element miniaturized adaptive antenna array. The adaptive antenna array is tested against a 2MHz broadband jamming signal under both laboratory testing conditions and a real jamming environment. Approximately 40dB anti-jamming range was achieved in the laboratory testing conditions. 38dB and 42dB were obtained in a real jamming environment with different antenna configuration. The likely performance limitations and possible further performance enhancements are also outlined in this thesis. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1363608 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Electrical and Electronic Engineering, 2008