Can a large number (say 15-20) of Wi-Fi access points affect the accuracy negatively?

Not at all! As a rule of thumb, the more access points around you, the better results you can expect from our solution.

Contrarily to our indoor location “hardware” solution (Accuware Wi-Fi Location Monitor), the Wi-Fi access points don’t have to be all strictly on the same channel. Even if it is possible to set them on non-overlapping channels (1, 6, 11) if needed, it will be fine if the entire network runs on the same channel.

However, access points far away and having a weak signal are not going to provide very useful information for positioning, so having many weak Wi-Fi access points does not really make the locations more accurate.