Indoor Navigation Based on Doppler Measurements

Nowadays a lot of different services are brought to the user using wireless infrastructure. To enhance these services an information about the users actual position is often desirable. To obtain this information additional sensors have to be installed. As Doppler processing can easily be integrated in already existing indoor infrastructure, position finding systems based on Doppler measurements would be preferable. This paper presents a position finding system that relies on the simultaneous Doppler measurement of an object by four sensors at different positions. The four Doppler signals are evaluated to obtain position and velocity of a single moving target by iteratively solving a nonlinear system of equations. Methods to assess the obtainable accuracy as well as first simulation results will be discussed. A 4-channel CW-radar as a demonstration system is presented.