US Patent 9977113 Method of determining position and cooperative positioning system using same

A positioning system is disclosed. The positioning system has a map database, a processing engine and a plurality of wireless communication devices including at least a first wireless communication device at a known position and a second wireless communication device at an unknown position. The processing engine determines the position of the second device based on the RSS measurements of a wireless signal transmitted between the first and second devices, the inertial measurements from the second device and the position of the first wireless communication device.