Impact on Critical Societal Services Caused by Jamming of UAS

This report describes the impact that intentional electromagnetic interference against UAS may have on critical societal functions. The report is primarily intended to work as an aid for the Swedish Police, when making a proportionality assessment concerning the use of force when counteracting UAS using jamming. The main frequency bands that are treated are the ones used by commercially available UAS. Thus, the report mainly concentrate on the following radio systems and frequency bands:  GPS and other satellite navigation systems (GNSS)  wifi-networks (2.4 and 5 GHz bands)  433 and 868 MHz, used for unlicensed short distance communications  mobile telephony systems. Furthermore, the study also includes the following frequency bands and radio systems:  869 MHz, which is adjacent to 868 MHz and used for different types of alarm.  915 MHz, which is used by UAS in other regions, such as USA.  GSM-R, which is used for railway communication and uses a frequency band within the 915 MHz frequency band.  5.875 - 5.925 GHz, which is adjacent to the 5 GHz band and used for vehicle communication.  RAKEL and TETRA. The study in this report focuses on jamming during a relatively short period of time (ten to several tens of minutes) and any potential impact it may have on systems in close proximity to the jammer. The study includes a broad examination of how critical societal systems may be affected during interference incidents. The analysis is based on unclassified publications. The report also provides guidelines that should be taken into consideration when constituting requirements for a jammer waveform. These guidelines are mainly devised in order to minimize the impact of the interference on non-targeted systems, but may in many cases also increase the effectiveness of jammer on the targeted system. The guidelines mainly pertain to usage of directional antennas, suitable transmit power, bandlimited interference signal, follow jammer when it is possible, and protocol specific jammers. These guidelines are also based on unclassified publications. Injury and even fatality may occur during very unfortunate circumstances, as has been reported in singular cases. In general, there is a rather low risk that intentional jamming during only a couple of tens of minutes would result in any severe consequence. Generally, critical societal services that use the studied frequency bands should not depend on real-time information, but rather be able to advert to redundant systems. Nevertheless, many of the studied frequency bands are used by different types of alarm system and industrial control where interference may cause injury or severe damage. The risk of irritation and confusion is always present when applying intentional interference in the considered frequency band. This stems from the fact that these bands are used extensively by a large variety of services and systems, both privately as well as commercially.