Indoor passive ranging based on WiFi

In this paper, we briefly analyzed the advantages of passive distance measurement based on Wireless Fidelity (WiFi). Based on the analysis of the principle of traditional interferometer direction finding, we derived the equations which are suitable for indoor distance measurement. Through theoretical analysis and simulation, we prove the correctness of the equations. Finally, we analyze and conclude the conditions of using the method, the scope of distance measurement, and the main influencing parameters of system accuracy.