The satellites serve to locate the vehicle. The duration of the vehicle ultrasound signal is transmitted to all the satellites and therefore, the position of the vehicle can be precisely determined with an accuracy of 10 mm. Depending on the size of the system, 3 satellites are necessary for the fully automated digital operation of the Car System Digital. Kit contains This building kit contains: 42 single parts in 3 colours and 1 construction instruction. Use for handicrafts FALLER - plastic glue. Dimensions: 181 x 302 x 108 mm Category: Car System Digital Track gauge: HO Construction instruction x1