One of the most widely used method for the positioning of unmanned aerial vehicles (UAVs) is satellite navigation. Positioning accuracy using the Global Navigation System (GPS) open service is several meters in horizontal direction and around 5 meters in vertical direction. Using augmentation systems the accuracy and integrity of GPS positioning can be improved. First I give a quick overview on the fundamentals of satellite navigation, and various augmentation methods, which increase the accuracy of positioning. For my thesis I designed a small and lightweight navigation sensor combining a GPS receiver and a digital compass. The design is based on the u-blox NEO-7P GNSS module and on the Honeywell HMC5883L magnetic sensor. The NEO-7P module is capable of using SBAS (Satellite Based Augmentation System) corrections and it’s proprietary PPP algorithm can further reduce positioning errors. By conducting different measurements I analysed the operation and accuracy of the magnetic sensor and came to the conclusion that it can be used to determine horizontal orientation with 5° error. The extensive testing and measurement of the GPS receiver was conducted under static and dynamic conditions. Based on the results the designed navigation sensor can provide dynamic positioning onboard UAVs with less than 2 m horizontal error (99%). Finally I present a method to implement a local and portable differential setup with two sensors which can significantly improve positioning accuracy.