The third iteration of China’s BeiDou satellite navigation system is expected to be completed by 2020. Credit: China Satellite Navigation Office

PARIS — The China Satellite Navigation Office expects to complete the buildout of its third-generation BeiDou positioning, navigation and timing — plus 2-way messaging — network by 2020 with the launch of three satellites this year.

The satellites, once in service, will complete the four-year BeiDou-3 (BDS-3) development phase, which has already seen the launch of 14 medium-Earth-orbit satellites and, most recently, a geostationary-orbit satellite launched in November.

The navigation office in December declared the primary BDS-3 system completed despite the coming launch and verification of the GEO-orbit satellites.

The spacecraft launched in November is still in test phase and is expected to be validated for service by June, said Jun Shen, deputy director of the navigation office, in a presentation to the March 25-27 Munich Satellite Navigation Summit.

The three GEO satellites — to operate from 80 degrees East, 100.5 East and 140 East — will make up the space-based augmentation system for the BeiDou MEO-orbit fleet and offer CAT-1 precision approach for commercial aircraft in China and the surrounding region.

The three satellites will also provide short messaging capability for the region, with a capacity of up to 10 million messages per hour with an average message size of 14 kilobits.

A global short-message service from BeiDou, with lower capacity, is scheduled for introduction after its 14 MEO-orbit satellites are in orbit. Eight of them have been launched, and are being tested, Shen said. The system’s capacity is 200,000 messages per hour at 560 bits per message.

China is promoting market adoption of BeiDou devices. Credit: China Satellite Navigation Office

BDS-3’s Search and Rescue service, using standards developed by the International Maritime Organization (IMO) and the Cospas-Sarsat organization, will be provided from six MEO-orbit satellites carrying Search-and-Rescue payloads.

Two of these MEO satellites have been launched with four more coming soon, Shen said, without being more precise.

Finally, BDS-3 2ill offer precise-point positioning service through the three GEO-orbit satellites covering China and its environs. Shen said the service will include the broadcast of precision-positioning information from several navigation systems.

China and the United States in 2017 signed a statement agreeing that BeiDou and the U.S. GPS systems would be mutually compatible and interoperable. In 2018, China signed a cooperating agreement with Russia regarding the Russian Glonass positioning, navigation and timing network.

China is undertaking many of the same market-stimulation efforts for BeiDou as Europe is for its Galileo satellite navigation network. Shen said high-precision BeiDou products are now available in 90 nations, and that 6 minion buses and other speciality road vehicles, plus 30,000 postal vehicles, have been equipped.