In-air sonar system and a method therefor

An in-air sonar system for determining location and velocity information of objects in an environment, the in-air sonar system comprising at least two emitters configured to emit respective sound signals into the environment, the respective sound signals having a low cross-correlation among each other;

• at least two receivers configured to receive sound signals from the environment;
• and a processing unit configured to perform:
• obtaining, from the at least two receivers, respective received sound signals comprising the respective emitted sound signals reflected from objects in the environment;
• calculating, from the respective received sound signals, velocity-dependent range maps for the respective emitted sound signals;
• the velocity-dependent range maps comprising information about the range and velocity of the respective objects;
• deriving, from the calculated velocity-dependent range maps and the spatial diversity of the at least two emitters and the at least two receivers, a velocity-dependent range-direction map comprising range information as a function of a received direction;
• determining therefrom a location of the respective objects;
• and
• extracting, from the velocity-dependent range maps and the spatial diversity of the at least two receivers, a velocity of the respective objects based on the determined location.