Sonar stands for SOund Navigation And Ranging and as a technique it is used for navigation, communication or detection of vehicles. It can be divided into two subclasses, active and passive. With active sonar pulses of sound are emitted and bounced back by objects which can be heared. Passive sonar only uses listening to sounds made by vessels to detect them. The SEGA robot only uses the active version.
The sonar consists of a transmitter and a receiver, which can be the same unit, two units or more different units. These are respectively monstatic, bistatic and multistatic operation. Sonar uses a pulse of sound, also called a ‘ping’, which can then be heared as reflections, also called an ‘echo’. With this echo you can calculate the distance it has travelled by using the time it took between the sending of the pulse and the receiving of the reflexion and the speed of sound. With this distance you can estimate you position relative to other objects, what is what we want.
The sonar sensor uses sound pulses to determine the distance from the sensor to an object. This is done by timing how long it takes from emitting the pulse until a reflection of that pulse is received. Because we know the exact position and angle of the sonar sensor relative to the robot, we can transform the measured distance to relative (x, y) coordinates.
While the sonar is somewhat similar to the laser, it has a much more limited range of 5 meters. The level of noise per distance is ±0.001m.
The sonar component receives the time of measurement and the distances from the 8 sonar sensors from the network relay component, transforms them into 2D points, and relays them to all connected (higher level) components.
The laser component accepts the following commands:
triples as parameters. Broadcasted to all incoming connections.