Final Report of BeJamDetect Project 
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Figure 5-14 - GUI snapshot at time of very strong event at 19:29:57 UTC on October 23 
The pulsed wideband signal that caused the 15.8 dB increase of input power did not cause 
significant losses on the satellites tracking, but did damage the quality of their received signals 
reducing them in over 10 dB-Hz wrt. nominal levels (usually between 45 and 55 dB-Hz depending 
on the elevation of the satellite). This can lead to innacurate information about the positioning, 
timing and velocity if the receiver is not equipped with other sensors or strategies to smooth fast 
and suspicious fluctuations. An example of a security measure against this problem is the coupling 
of GNSS with inertial sensors or inertial navigation systems. 
On Figure 5-15, one of the multiple events from October 24 is reproduced through the snapshot 
of the GUI at that time, when the input power raised over 9 dB. In spite of the power of many of 
these events (raising between 6.4 and 17 dB the input power), most of them did not cause major 
problems to satellites tracking, but only to the quality of the signal, similarly to what happened on 
the previous day. 
The type of interference that caused these multiple strong detections throughout both days is 
similar, a sort of sequence of short wideband pulses, and have all a strong direction-of-arrival 
correlation between them: all pointing towards southwest wrt. the ship’s heading. Moreover, 
during the time of both clusters of RFI detection the ship was on open sea close to Fehmarn and 
to Lolland, Denmark (see again Figure 5-11), stationed on October 23 between 19 and 21:00 and 
slowly moving on October 24. 
Title: Final Report 
Version: 1.0 
age: 86