Confidence field meaning

[vasimv]

Usual reports have confidence field (fifth byte for 88 bytes length or sixth byte for 89 bytes length report) in 0..3 range (0 is worst and 3 is best). But at some point, i'm receiving reports with confidence field values up to 183 (decimal).

Anyone have an idea what does this means and why it was changed?

[sonman]

Thanks for the hint that confidence field is 6th (not 5th) byte in 89 reports.

[sonman]

I also saw a confidence value of 131 (0b10000011) two days ago. Maybe only the first 2 bits are used for "confidence" and not the full byte?

[Chapoly1305]

Usenix 2025 Locating You from a Thousand Miles Away: Turning a Computer into an Apple AirTag Without Root Privilege Escalation.

Greater the confidence, the smaller scatters. 1 is the least reliable location report.