Global Positioning System (GPS) jammers add excessive noise to the received low power GPS signals and have capability to either weaken or completely destroy the positioning performance of GPS receivers for both civilian and military users. Researchers are actively working to develop GPS receiver systems resistant to interference sources. Our aim is to develop a system based on spatial filtering of jamming signals through the use of an active antenna array which is capable to control its radiation pattern by utilizing signal processing techniques. Array radiation pattern is controlled to maximize gain in satellite directions and to create null regions toward jammers. Adaptive beamforming methods provide necessary weighting coefficients to form desired radiation patterns using received data. In this paper, design, production and tests of an active antenna array is presented with implementation of adaptive beamforming algorithms using commercially available development boards.