Devices and methods are disclosed that can determine the location of an object in 3d space based on low-cost, small, battery powered devices that can be used in an indoor setting. The “Dots” operate using a combination of low power wireless communication and ultrasonic sound. The wireless communication may be typically BLE, Thread or WiFi. Dots also are provided basic processing ability and an ultrasonic microphone capable of sensing. Dots are passive and are controlled by the device whose location is being identified, referred to as the Control Point (CP). Multiple Dots are placed within an indoor space and distance to each Dot is determined by measuring time taken for sound to travel between each Dot and the CP. The system is capable of providing indoor location accurate in 3d space to within a foot or less and can be used for navigation, or tracking of pets or children.
Cornell, Brian, "Low-Cost Indoor Micro-Location", Technical Disclosure Commons, (April 05, 2017)