Final Report of BeJamDetect Project 
2. Introduction 
Current global navigation satellite systems (GNSS) like the American GPS and the European Galileo 
make use of satellite constellations at medium Earth orbits (MEO). The navigation signals 
transmitted by the GNSS satellites flying at the altitudes of more than 20000 km above the Earth 
are received by a typical user at very low power levels smaller than a femtowatt (107° W). So, for 
axample, the minimum received power level provided by system operators for GPS and Galileo 
>pen service signals in L1 frequency band is -160 dBW [1, 2]. Because of such low power, the 
analogue RF front end of the navigation receiver requires to provide in total of about 100 dB 
amplification for the received signal before it can be digitised and processed in the baseband digital 
Jart of the receiver. The RF front end also performs filtering of the signal in order to reduce the 
effect of the out-of-band portions of received spectrum. Because of the low signal power and high 
amplification required, the reception and processing of the GNSS navigation signals is very 
susceptible to Jamming effect which can be caused by a stronger signal from another radio system 
in the same or adjacent frequency band [3]. The severity of the jJamming effect depends on many 
aspects where the most important ones are, however, the parameters of the interfering signal 
‚power, time-domain behaviour and spectral characteristics) as well as the design of the navigation 
‚eceiver, i.e. how good the receiver is prepared to encounter the interference both on the sides of 
analogue hardware and digital signal processing. The worst case is often considered the situation 
where the Jamming leads to such significant distortion of the reception of the navigation signals 
that the positioning and timing services of GNSS become unavailable. Unfortunately, suitable 
jJamming devices able to create such an outage of the GNSS services, though illegal to use in the 
majority of industrially-developed countries, are easily available to buy in online shops like 
stoersender24.com. One of the most well-known jJammer-types used by private persons Is so called 
Dersonal-privacy device (PPD, see Figure 2-1) which is intended for blocking a local GNSS-receiver 
Jsed for tracking a platform (e.g. a car) or a person. In a maritime environment, such jJamming may 
appear in the costal or harbour area as well as on the board of a transport ship. 
A 
Mini GPS Tracker 
Störsender für Autos 
49:00 €42,00 
Dieser Mini-KFZ GPS Störsender hat eine 
:requenz von 1500 bis 1600 MHz und ist 
gemacht für Störobjekte wie z.B. der GPS 
L1 Tracker, GPS Navigator und der GPS L’ 
ogger. 
EACH: 
Kategorie: GPS Störsender 
DOSE 
Figure 2-1: Example of a Jammer — a personal privacy device (PPD), 
a screenshot of the product page on https:/www.stoersender24.com/ 
Fitle: Final Report 
Version: 1.0 
7e.