DuckLink Positioning System (DPS)
In simple terms, the DuckLink Positioning System (DPS) is a solution when Global Positioning Systems (GPS) fails to work. GPS uses artificial satellites to approximate the location of a device and it works wonders! People can get from point A to point B without fiddling with a paper map. However there are some limitations to GPS. Two of the limitations are when the device cannot connect to the satellite or if devices are indoors.
It is self-explanatory why GPS doesn’t work if it cannot connect to satellites. If it cannot connect to satellites, it cannot calculate location. GPS doesn’t work indoors because of a couple of reasons. If the indoors has multiple floors, GPS cannot detect what floor is a device on. Another reason is sometimes the error of the GPS can sometimes be greater than the indoor space. The DPS was created to solve these problems. It is a low cost, low power, high accuracy alternative to GPS for indoor localization.
Before diving in the DPS process, we should introduce two new different types of Ducks: StationaryDucks and MobileDucks. StationaryDucks are Ducks that are deployed in known locations throughout the building. Their job is to consistently ping and to generate a mesh network. The MobileDucks are basically “lost” Ducks that need to be located. They listen carefully for pings from the StationaryDucks, record the signal strength of each ping, and send that data up into the mesh network.
How does this process help us? We collect signal strength because it is related to distance; the stronger the signal is between two devices, the closer they are. If a MobileDuck receives a strong signal from StationaryDuck A but a weak signal from StationaryDuck B, then we know the MobileDuck is closer to A than B. Using this relation, we can infer the location of the MobileDuck.
