The arbitrator and the sensors use a common configuration library which makes it easy to parse configuration information from the command line and configuration files. Since the sensors and the arbitrator can run on any machine on the Robocar network, it is simple to add and remove computers to and from the system as needed. The arbitrator spawns sensors at startup using rsh . A simple command protocol allows communication between the sensors and the arbitrator over the network. The arbitrator can get and set a sensor's configuration, get a single suggestion from a sensor, set a sensor's suggestion rate and kill a sensor.
Occupancy grids are just a way of representing world information in a grid format.
Our occupancy grids are 6 meters wide and 3 meters high and have ten grid points per meter. The car is centered in the middle at the bottom of the grid. These are not acknowledged by the arbitrator and can get dropped if the network gets bogged down. This protects the arbitrator from sensors that send suggestions too fast. Time stamps on the suggestions lets the arbitrator know how old the suggestion is.