Since 2022, DLR’s Mobile Rocket Base (MORABA) has observed jamming of GNSS signals on sounding rockets launched from Esrange in northern Sweden and Andøya rocket range in northern Norway. Within these flights, different types of single-frequency and single- or multi-constellation GNSS receivers were used.

The jamming primarily affected the GPS L1, Galileo E1 and BeiDou B1C and B1I signals on the L1 frequency band and was noticeable through a pronounced reduction of the carrier-to-noise ratio of the received GNSS signals. Jamming was observed in northern Sweden at an altitude above 25 km and in northern Norway at an altitude above 36 km. Geometric considerations made it possible to roughly localise the source of the jamming signals from the points of the flight path marking the start and end of interference.

The MAIUS-2 sounding rocket, which was launched from Esrange in December 2023, was equipped with an advanced GNSS receiver that was able to analyse the power spectrum of the GNSS signals online. This made it possible to identify the frequencies and bandwidths of the jamming signals on the L1 frequency band.

The flight guidance and range safety of future micro launch vehicles to be launched from the new spaceports in Sweden and Norway, may be affected by the GNSS jamming if their navigation systems overly rely on the availability and quality of a GNSS navigation solution. Manufacturers and operators should be aware of the possible presence of intentional GNSS jamming in northern Scandinavia and the risk of losing or degrading the GNSS navigation solution during parts of the critical guided flight phase.

The paper summarises the GNSS jamming events observed on the recent sounding rocket flights, presents a geometric analysis for identifying the approximate jammer location, and shows the results of the power spectrum analysis on the MAIUS-2 sounding rocket.