A robotic system including at least two acoustic sensors, spaced apart, for receiving respective versions of a respective continuous ultrasonic waveform emitted by each of one or more positional elements, each of the respective continuous ultrasonic waveforms comprising a respective modulated carrier and an electromagnetic sensor for receiving a respective electromagnetic signal emitted by a respective electromagnetic emitter of a same respective one of the positional elements, and a computing device. The respective electromagnetic signal is emitted in coordination with the respective ultrasonic waveform emitted by the same positional element. The computing device decodes the versions of the ultrasonic waveform and the electromagnetic signal to measure time delays between the versions of the respective ultrasonic waveform and the respective electromagnetic signal, converts the time delays to distances, and triangulates the distances to determine positions of the positional elements. A robot maneuvers based on the determined positions.