Devices, systems and methods for navigating and determining the location of downhole oil and gas wellbore tools are disclosed. The devices, systems, and methods may include a drone including an ultrasound transceiver that generates and receives an ultrasonic signal that interacts with the environment external to the drone and detects, utilizing a processer associated therewith, changes the environment external to the drone. The speed and location of the drone may be determined using the processor. Alternatively, an electromagnetic field generator that generates a field that interacts with the environment external to the drone. When the drone moves through the wellbore, the environment external to the drone constantly changes. Based on this changing environment, the speed and location of the drone is determined using the present devices, systems and methods.