Use of the global positioning system is all around us. From the satnav in your car to quadcopters hovering above a point, there are hundreds of ways we use the Global Positioning System every day. There are a few drawbacks to GPS: it takes a while to acquire a signal, GPS doesn’t work well indoors, and because nodes on the Internet of Things will be cheap, they probably won’t have a GPS receiver.
These facts open up the door for a new kind of positioning system. A local positioning system that uses hardware devices already have, but is still able to determine a location within a few feet. For his Hackaday Prize entry, [Blecky] is building the SubPos Ranger, a local positioning system based on 802.15.4 radios that still allows a device to determine its own location.
The SubPos Ranger is based on [Blecky]’s entry for the 2015 Hackaday Prize, SubPos that used WiFi, RSSI, and trilateration to determine a receiver’s position in reference to three or more base stations. It works remarkably well, even in places where GPS doesn’t, like parking garages and basements.
The SubPos Ranger is an extension of the WiFi-only SubPos, based on 802.15.4, and offers longer range and lower power than the WiFi-only SubPos system. It’s still capable of determining where a receiver is to within a few feet, making this the ideal solution for devices that need to know where are without relying on GPS.