Low-budget passive locating system for IoT applications: analysis and implementation.

This paper focuses on problem of locating IoT devices in open area. There are basically two location methods from the IoT implementation point of view: active and passive. Active methods work great if we have opportunities and resources to implement data exchange and location systems in usually small IoT devices. Passive methods could be more efficient on calculation and hardware basis for locating devices with their own low power radio signal, but without need of data transfer. Passive methods are discussed in this paper. Target is successfully reached when observer can locate object in reasonable distance. Another factor is overall cost of the system. Low cost software defined radios in combination with embedded computing platforms can capture signal and pass it to cloud services. Data processing is live operated to present location information with small latency. Two concepts of passive measurements are presented: measurement of amplitude and arrival time differences of signals obtained at three receivers. These two methods combined can possibly give opportunity to achieve results with a sufficiently small measurement error.