The open service, Open Service(OS), is the basic service for the GPS system and Galileo, and can be used free of charge. The position resolution of the OS service is 15 m horizontally and 35 m vertically and is received with a single frequency receiver. The position accuracy can be increased to 4 m by using dual frequency receivers. The transmit frequency is 1,575.42 MHz and is the same for the two systems mentioned.
The open service is not guaranteed in its availability. In addition to the open service, Galileo also offers the Commercial Service( CS), the Safety-of-Life Service ( SoL), the Public Regulated Service( PRS) and the Search and Rescue Service( SAR).