MLAT error or error in ICAO?

[rugomol]

What is the problem if the plane is visible under “~E2F1B4” code?
What does the “~” sign mean?

MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:36:29.927,2020/09/22,14:36:29.927,39503,337,284,43.5459,31.8886,1, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:36:36.015,2020/09/22,14:36:36.015,39503,341,285,43.5485,31.8758,9, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:36:41.104,2020/09/22,14:36:41.104,39503,335,284,43.5508,31.8639,7, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:36:48.655,2020/09/22,14:36:48.655,39508,339,284,43.5545,31.8446,28, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:36:56.660,2020/09/22,14:36:56.660,39510,339,285,43.5579,31.8281,29, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:37:03.402,2020/09/22,14:37:03.402,39512,336,284,43.5598,31.8155,26, ,
MLAT,3,1,1,~E2F1B4,1,2020/09/22,14:37:09.489,2020/09/22,14:37:09.489,39515,334,284,43.5628,31.8014,31, ,

[jonhawkes2030]

I believe that they are annonymised MLATs. These are transponders that don’t want to be tracked. Celebrities, CEOs and other VIP aircraft that don’t want to be tracked.

[rugomol]

This is Bombardier Challenger 650 ARTEMIS (Airborne Reconnaissance and Targeting Multi-Mission Intelligence System)

[obj]

@rugomol

What does the “~” sign mean?

As jon says, these are anonymized mlat results for a blocked aircraft. The leading ~ (or the italics on the skyaware display) indicates that it is not an ICAO address, you’ll see the same for e.g. TIS-B track file identifiers.