###### Abstract  
The global navigation satellite system (GNSS) signals are vulnerable to disruption sources, such as signal jamming. This, in turn, can cause severe degradation or discontinuities of the GNSS-based position, navigation, and timing services. The availability of multi-frequency signals from multi-constellation GNSS systems, such as Galileo and GLONASS, along with the modernization of GPS with multi-frequency signals, has the potential to increase the immunity of GNSS-based navigation systems to signal jamming. Despite various studies completed on the utilization of multi-frequency and multi-constellation global navigation satellite system (GNSS) signals to resist receiver jamming, there is still an urge to further investigate this concern under different circumstances. This paper presents an experimental evaluation of the advantages of the employment of multi-frequency multi-constellation GNSS signals for better GNSS receivers' performance during signal jamming situations for high-dynamic platforms such as aircraft/drones. Additionally, the study examines the effects of both simulated and real jamming signals on all possible combinations of the GPS, Galileo, and GLONASS signal frequencies and constellations. Two airplane trajectory routes were built, and their corresponding RF signals were generated using the Spirent and Orolia GNSS signal simulators. The results indicated that the GPS multi-frequency-based solution maintains reliable positioning performance to some extent under low jamming scenarios. However, the combination of GPS, Galileo, and GLONASS signals proved its ability to provide a continuous and accurate positioning solution during both low and high jamming scenarios. GNSS; jamming; multi-constellation; multi-frequency; interference; navigation and positioning; autonomous vehicles 2023239552  
26 October  
the deliberate transmission of radio frequency signals on the same frequency as the GNSS signals, overpowering or disrupting the reception of these signals by GNSS receivers [11]. The consequences of jamming in safety-critical applications can be severe, leading to deteriorating positioning accuracy or even complete loss of position information for a large area around the jammer, depending on the inserted jamming signal power [12]. The use of multi-frequency and multi-constellation GNSS signals has the potential to mitigate the effects of jamming and enhance the reliability of the positioning solution. By employing multiple frequencies and signals from different constellations (such as GPS, GLONASS, Galileo, BeiDou, etc. ), the receiver gains several advantages. First, this will add high signal redundancy, ensuring that if one signal is jammed or made unavailable, the receiver can still rely on other signals to maintain accurate and continuous positioning. Second, access to multi-frequency signals from different constellations grants the receiver a higher chance of receiving more useful signals; thus, enhancing the received signal strength and hence improving the positioning accuracy and availability. Third, a receiver capable of tracking several signals from various frequencies and constellations can effectively identify anomalies in signal behavior, enabling the detection and mitigation of jamming signals. The objective of this paper is to extensively explore the advantages of using multi-frequency multi-constellation GNSS over GPS-only systems regarding signal jamming resistance and positioning solution availability. To achieve this goal, two trajectories are simulated using the Orolia GNSS simulation engine. The simulated data are then either altered by an internally simulated interference signal or hit by a real jamming signal generated by the NavWar Electronic Attack Trainer (NEAT) jammer. These jamming tests took place within the controlled environment of an anechoic chamber room at the Royal Military College of Canada (RMCC). The output trajectory data are then collected using the NovAtel PwrPak7 GNSS receiver.