A GPS Patch Antenna Array for the ESA PRETTY Nanosatellite Mission

The PRETTY mission is a satellite mission of the European Space Agency (ESA) with the goal to demonstrate the concept of passive reflectometry with a small and cost-efficient 3U Nanosatellite. Passive reflectometry allows the characterisation of the Earth surface properties and height, by correlating direct and reflected Global Positioning System (GPS) signals. The PRETTY mission focuses on the characterisation of the surface height. The system is realized as a Software Defined Radio (SDR) with a high-gain GPS patch antenna array that receives the very weak reflected signals from Earth's surface. The GPS patch antenna array resides on the outer surface of the satellite with direct contact to the harsh space environment. The application in space is a key factor for many requirements and design restrictions for the PRETTY GPS antenna array. This paper focuses on the various design constraints and requirements for the antenna array and describes the relations with the antenna design parameters. The paper describes the results obtained from a first single patch simulation and discusses the final antenna array architecture, simulation results and PCB design.