The invention replaces the conventional way of encoding sensory information based on arrays with a small, dynamic emitter and/or receiver. Conventional sonar (and radar) encode direction-dependent information by scanning the environment with narrow beams. Creating these narrow beams requires arrays with large numbers of elements and a diameter that exceeds the utilized wavelengths by one or several orders of magnitudes. The invention uses direction-dependent time-variant signatures to replace the narrow spatial beams that can hence shrink the size and complexity of the sensory system. This makes the invented sensing device a replacement for conventional arrays for applications that impose limits on size, device complexity, power consumption, and computational bandwidth. Examples for such applications are small autonomous underwater and aerial vehicles. Additional applications could be in the area of recording mixtures of signals that arrive from different directions, e.g., as a front-end for speech processing in noisy environments.