Final Report of BeJamDetect Project 
NIELLLS U 
WA LU 
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Figure 3-25: Geographical distribution of the main L1 RFI events between June 1 and November 11, 2021 
In Figure 3-26, the distribution of these occurrences is further treated in details regarding the month 
of appearance, and the strength of these events. 
According to Figure 3-26a, In the first three months of the measurement campaign the DENEB ship 
was much more affected by RFI than in the last three months. Although November only ran until 
the 11th, there were only 79 detection triggered interference snapshots, yielding an average of 
approximately 7.2 per day, which is much smaller if compared to the averages of June and July, 
respectively 38.7 and 35.3. This phenomenon is much likely associated with the locations of the 
ship during June and July, compared to the other months—even August had 24.4% less detections, 
in average, than these two months. 
The duration of each snapshot is of 30 ms. While possible that interference occurrences lasted for 
longer than this time, it’s not possible to determine exactly how much, because the exceeded time 
is not recorded. For this end, the time under RFI influence is determined through two approaches, 
ane yielding an optimistic result and another yielding a pessimistic result. 
The optimistic approach is to count the number of RFI snapshots succeeding RFI snapshots. In this 
way, it can be counted how many snapshots were recorded in a row and then multiply this number 
by the dead-time period (30 s), yielding the estimated time under which RFI was present and 
detected by the receiver. The results for each month can be seen on Figure 3-27, with a total time 
af 32 hours and 16 minutes under RFI during the whole campaign. It’s clear, nonetheless, that this 
approach can still be considered to overestimate the duration of each snapshot, since only in a few 
times during the whole campaign has the receiver recorded consecutive snapshots after exactly the 
dead-time period (30 s). In other words, in most of the times, there are no absolute evidences that 
the RFI signals lasted between two consecutive snapshots. 
Title: Final Report 
Version: 1.0 
age: 30