Accelerometers, Gyros, GPS, & Compasses. Measure acceleration and track rotation with these accelerometers, gyroscopes, compasses/magnetometers, and combined inertial measurement units (IMUs) and orientation sensors.
Mount beacons on walls or ceilings to measure distance to other beacons and “hedgehog” using ultrasonic pulses. They communicate with router wirelessly in ISM band. Powered by LiPo battery or USB. The beacon has a built in Inertial Measurement Unit (IMU).