Error analysis of a low cost TDoA sensor network

Geolocation methods are recently gaining a lot of interest due to their new range of applicability. Location based mobile services as well as frequency regulators aiming at efficient spectrum usage are interested in flexible, low cost geolocation systems with high accuracy. One method that meets those requirements is Time Difference of Arrival (TDoA). It has been subject to research for many years now. The main focus of research published about TDoA is presenting new algorithms or calculating estimation bounds in different scenarios. Due to new low cost available hardware solutions, a simple TDoA system can be built and used as a testbed for different algorithms in different real scenarios. This contribution presents an error analysis of a TDoA sensor network using low cost, off-the-shelf software defined radio platforms. The system relies on GPS time stamps provided by the platforms. Five important TDoA error types caused by hardware as well as different channel effects are analyzed. Each error is analyzed in its influence on the position estimate and a possible solution is given. Finally, a general structure of how a smart TDoA system should work is described.