Geo-location estimation from Electrical Network Frequency signals

Electric Network Frequency (ENF) fluctuations based forensic analysis is an emerging way for such multimedia authentication tasks as time-of-recording estimation, timestamp verification, and clip insertion/deletion forgery detection. ENF fluctuates due to dynamic changes in load demand and power supply, and these fluctuations travel over the power lines with a finite speed. In this paper, experiments are conducted on ENF data collected across different locations in the eastern grid of the United States to understand the relationship between the signals recorded at the same time at these locations. Based on these experiments, a signal processing mechanism is developed to demonstrate that ENF fluctuations across different locations exhibit a measure of similarity with each other, which is proportional to the distance between the locations. Such observations motivated a location estimation protocol based on the similarity of ENF signals with respect to anchor nodes. Under certain conditions, the proposed protocol is shown to provide an estimation accuracy of 90%. Challenges in the application of ENF signal analysis for location of recording estimation of multimedia signal are also discussed.