I found out that using the network/wifi based location on my android device I can get quite an accurate position from my home wifi router (without using GPS). Obvoiusly for that to work, Google must know the position of my home wifi router.
So my question is: how does google know the position of my home wifi router?
TY for you time.
Google knows the position of your home WiFi router using IP address location systems.
Simply put, IP address location systems (which are a kind of geolocation) are algorithms that can determine the location of an IP address by examining certain characteristics of the traffic coming from the address, or by looking at the addresses's associated data.
For more information, look at Geolocation and IP address location on Wikipedia.