Global Navigation Satellite Systems (GNSSs) have become a critical part of the infrastructure of modern society. Radio interference can introduce position or timing errors in systems that use GNSS or, in a worst-case scenario, block the reception of GNSS signals in full. Part of this critical infrastructure is, among others, power plants, banks, and transport. Interference of GNSS signals could originate from nature, such as solar activity or ionospheric effects. Other interference could originate from unintentional sources (e.g., radio signals from a malfunctioning radio tower) or intentional sources such as a jamming or spoofing device. The latter is what this thesis will focus on. This thesis consists of two parts. The first part is about jamming and elaborates on the impact of seven different forms of jamming on two types of GNSS receivers, a time-worn receiver and a cuttingedge receiver. The cutting-edge receiver has as option to turn on Interference Mitigation (IM). The performance of both receivers is the roughly the same in case the IM is turned off on the cutting-edge receiver. However, when the IM is turned on the cutting-edge receiver clearly is more resillient to the jamming signals. In the second part of the thesis various types of spoofing are discussed. Due to time and hardware restrictions it was not possible to perform synchronous spoofing, which is an advanced form of spoofing. Instead, various concepts are discussed that describe how synchronous spoofing could be achieved.