Testing has begun on Europe's Galileo navigation satellites intended to offer highly accurate services to authorized users, officials said.

Transmitted on two frequency bands with enhanced protection, the Public Regulated Service (PRS) offers a highly accurate positioning and timing service to mostly governmental users, a release from the Paris headquarters of the European Space Agency reported Tuesday.

PRS access was initially planned for Galileo's Full Operational Capability phase by the end of the decade but was brought forward response to the strong interest of EU member states in the service, the ESA said.

The ESA has overseen the provision of several tools, including test receivers and other qualification equipment, for governments wishing to test the PRS system.

The ESA's technical center in the Netherlands provided training, demonstrations and sample data, the agency said.

"As a result, Belgium, France, Italy and the United Kingdom have now performed independent PRS acquisition and positioning tests," Miguel Manteiga Bautista, head of ESA's Galileo Security Office, said. "In parallel, ESA, through collaboration with Dutch and Italian authorities, is also conducting PRS fixed and mobile validation in several locations in the Netherlands and Italy."

The PRS tests have demonstrated a current autonomous positioning accuracy below 30 feet, an impressive result considering the small number of Galileo satellites in orbit -- just four so far -- and the limited ground infrastructure so far deployed, the ESA said.