Ultrasound-based localization of client devices with inertial navigation supplement in distributed communication systems and related devices and methods

A method of a RF communication client device configured to communicate in a distributed communication system for determining location within the distributed communication system, comprising:

• calculating a first position using ultrasound signals received at the client device;
• and
• calculating a second position from the first position using an inertial navigation system within the client device when a signal strength of the ultrasound signals falls below a predefined threshold,
• wherein calculating the first position comprises:
• recording sound received from a plurality of ultrasound beacons over at least one microphone over a defined period of time;
• filtering the recorded sound about at least one ultrasound beacon frequency;
• recovering a plurality of ultrasound pulses from the filtered recorded sound emitted from a plurality of ultrasound beacons in the distributed communication system;
• performing a time-difference-of-arrival analysis on the recovered plurality of ultrasound pulses;
• and
• determining a relative distance of the RF communication client device to the plurality of ultrasound beacons.