I'm not sure. It's very unusual to see even low levels of potential interference in that area. Looking at detailed stats using the history feature of GPSJAM PRO, I'd say it's likely there's a real effect that is having an impact on a significant percentage of aircraft in that area. It's true it can be tricky to figure out exactly what it is having an impact.
"# Good" is the number of distinct aircraft that flew through that hex that never reported low accuracy with their GNSS. "# Bad" is the number of distinct aircraft that at some point during their flight reported good accuracy with their GNSS, but some time after that, including while flying through that hex, reported low accuracy. I would say that based on the number of aircraft showing up as Bad, and the fact that it's just that hex seeing this effect, it's likely to be showing a real effect.
My list of the most common things that make an aircraft report low GNSS accuracy:
1. Intentional GPS jamming.
2. Unintentional GPS interference.
3. Aerobatics that cause the aircraft's GPS antennae to be masked from satellites by the body of the aircraft.
4. On-board equipment issues.
I think the data suggests it's not #4. #3 is typically seen in military operating areas (MOAs) in the U.S.; I don't know if there might be fighters practicing in the skies west of London.
Edit to add: FWIW I've gotten one report from a person in the yellow hex that they weren't able to get a GPS fix. That's all I know.
Data:
"# Good" is the number of distinct aircraft that flew through that hex that never reported low accuracy with their GNSS. "# Bad" is the number of distinct aircraft that at some point during their flight reported good accuracy with their GNSS, but some time after that, including while flying through that hex, reported low accuracy. I would say that based on the number of aircraft showing up as Bad, and the fact that it's just that hex seeing this effect, it's likely to be showing a real effect.My list of the most common things that make an aircraft report low GNSS accuracy:
1. Intentional GPS jamming.
2. Unintentional GPS interference.
3. Aerobatics that cause the aircraft's GPS antennae to be masked from satellites by the body of the aircraft.
4. On-board equipment issues.
I think the data suggests it's not #4. #3 is typically seen in military operating areas (MOAs) in the U.S.; I don't know if there might be fighters practicing in the skies west of London.
Edit to add: FWIW I've gotten one report from a person in the yellow hex that they weren't able to get a GPS fix. That's all I know.