If there are 3 or more WiFi networks in your area that can be received with differing dB (RSSI). you can use WiFi to get your starting points and point corrections. Consider using the Machine Learning algorithm KNN (Closest Known Neighbour) as a way to ID the point locations.
Like in roomX at a spot in the room with 3 WiFi RSSI's giving; say, -35,-78, and -89 db's. More WiFi RSSI's the more accurate the location. That point in the room can be used to dead reckon from until the thing gets to another RSSI intersecting point. At which time the things position could be updated. and the dead reckoning can be reset.
Anyways, that's an idea which has its pros and cons.