BeiDou Future and Evolutions

BEIDOU
Title	BeiDou Future and Evolutions
Edited by	GMV
Level	Basic
Year of Publication	2011

The BeiDou Navigation Satellite System (BDS), also known as BeiDou-2, is China’s second-generation satellite navigation system that will be capable of providing positioning, navigation, and timing services to users on a continuous worldwide basis.

BeiDou Roadmap

The BeiDou system is planned to be developed and deployed in three phases:

• Phase 1 (2003+)

Phase 1 consists of an experimental regional navigation system, BeiDou-1, which provided active navigation service.

• Phase 2 (2012+)

BeiDou-2 consists of a reduced satellite constellation and provides open service over China. This phase aims at deploying a system with passive positioning and timing capability over a regional area.

• Phase 3 (2020+)

By 2020, BeiDou would reach full operational capability with a Walker constellation of 27 MEOs plus 5 GEOs and the existing 3 IGSOs satellites of the regional system. BeiDou would provide global navigation services, similarly to the GPS, GLONASS or Galileo systems.

BeiDou Status

By December 2011, the BeiDou system went into operation on a trial basis providing initial passive positioning navigation and timing services for the whole Asia-Pacific region with a constellation of 10 satellites (5 GEO satellites and 5 IGSO satellites) and the Initial Operational Service was declared officially available.

During 2012, four launches were made in February, April, September and October, placing in orbit two adittional GEO and four MEO satellites in-line with the objective of expanding the service area to Asian-Pacific users and improving service performance (positioning accuracy better than 10 meters). The constellation is currently composed by 6 GEO + 5 IGSO + 4 MEO which corresponds to 15 operational satellites of the 35 planned. Furthermore, the first version of the SIS ICD for the BeiDou B1I open service signal was released on the 27^th December 2012 at a news conference held in Beijing by the Chinese State Council Information Office, where it was also announced that the english name of the system was now to be replaced with BeiDou Navigation Satellite System, instead of its translation, BeiDou.

On March 30, 2015, the China Satellite Navigation Office (CSNO) announced the successful launch of the first New-Generation BeiDou Satellite. This is the 17th satellite for the BeiDou Navigation Satellite System (BDS) that marks the beginning of expanding the regional BDS to global coverage, scheduled to be fully deployed by 2020.

On July 25, 2015, China launched two new satellites (18th and 19th) for the nation’s Beidou Navigation Satellite System. The spacecraft will be used to test the new BeiDou Phase III navigation signal and inter-satellite links. China will migrate its B1 open civil signal from 1561.098 MHz to a frequency centered at 1572.42. The signal modulation will also change from a quadrature phase shift keying (QPSKZ) modulation to a multiplexed binary offset carrier (MBOC)..

BeiDou General Services

The future BeiDou is expected to support two different kind of general services: RDSS and RNSS.

In the Radio Determination Satellite Service (RDSS) , the user position is computed by a ground station using the round trip time of signals exchanged via GEO satellite. The RDSS Long term feature further includes:

• Short message communication (guaranteeing backward compatibility with BeiDou-1)
• Large volume message communication
• Information connection
• Extended coverage

The Radio Navigation Satellite Service (RNSS) is very similar to that provided by GPS and Galileo and is designed to achieve similar performances.

International Context

The Chinese Government considers satellite navigation as strategic in the new generation information technology, and encourages international cooperation to ensure compatibility and interoperability with other navigation systems.