Development Report on BeiDou Satellite Navigation System-System Development

  1. System Planning

According to the overall requirements of “Quality, Safety, Application, Efficiency,” adhering to the development principle of being “Independent, Open-minded, Compatible and Gradual,” following the overall plan of “From regions to globe,” BeiDou Satellite Navigation System is making progresses steadily following “three steps.” The detailed development plan is as below:

Step One, BeiDou Satellite Navigation Pilot System

In 1994, China started the construction of BeiDou Satellite Navigation Pilot System. In 2000, two BeiDou Navigation Pilot Satellite were launched; the BeiDou Satellite Navigation Pilot System was completed. China became the third country in the world to own an independent satellite navigation system. In 2003, the third BeiDou Navigation Pilot Satellite was launched, which further boosted the BeiDou Navigation Satellite Pilot System’s performance. BeiDou Satellite Navigation Pilot System consists of three parts, namely, space constellation, ground control and user terminal. Space constellation consists of three GEO satellites, which are positioned at the equatorial longitudes of 80ºE, 110.5ºE and 140ºE. Ground control consists of ground control center and a number of calibration stations. Ground control center is mainly responsible for satellite orbit determination, ionosphere correction, user’s location determination and users’ short message information exchange. Calibration stations mainly provided distance measurement and distortion parameter for ground control center. User terminal includes various types of terminals such as the handheld ones, those used in vehicles, and those with remote control functions that can send location applications and receive position coordinates, etc.

The main functions and performance index are as below:

  • Main functions: positioning, one-way and two-way timing, short message information;
  • Coverage: China and its neighboring areas;
  • Positioning accuracy: better than 20 meters;
  • Timing accuracy: 100 nanoseconds in one way; 20 nanoseconds in two ways;
  • Short message communication: 120 Chinese characters per time.

Step two, BeiDou Satellite Navigation System Regional Service

In 2004, China started the construction of BeiDou Satellite Navigation Systematic Project. By the end of 2012, five GEO satellites, a network of five IGSO satellites and four MEO satellites has been completed, which enables the system to serve regional users. The main functions and performance index of BeiDou Satellite Navigation System’s regional services are as below:

  • Main functions: positioning, speed measurement, one-way and two-way timing and short message communication.
  • Coverage: It mainly covers China and the regional areas.
  • Positioning accuracy: on the same altitude, 10 meters; on higher altitude, 10 meters;
  • Speed measurement accuracy: better than 0.2 meters per second;
  • Timing accuracy: 50 nanoseconds in one way; 20 nanoseconds in two ways;
  • Short message communication: 120 Chinese characters per time.

Step3, BeiDou Satellite Navigation System serves global users.

Starting from 2014, China continues to launch more satellites into the network, in order to promote the regional service performance and to expend to the whole world. By 2020, about 30 BeiDou Navigation Satellites will be launched to realize the goal of making the system a global one.

  1. Current condition of the system

Until October 25th, 2012, BeiDou Satellite Navigation System has successfully launched 16 satellites. They have been operating in a network since the end of 2012. This network has been able to provide source localization service, navigation service and timing service for regional users, including users in China and most of its neighboring areas. BeiDou Satellite Navigation System is an additional resource of satellite navigation in Asia-Pacific Region. Through working with compatible systems, it is able to provide reliable and stable services. Currently, BeiDou Satellite Navigation System operates continuously and steadily, with competence in meeting fixed standards. In some areas, it has better performance than what the standard requires.

The Exoteric Service Performance Criteria of BeiDou Satellite Navigation System (1.0) has elaborated on the overall composition, space signal characteristics and performance criteria, features of the system’s service and performance standards of the BeiDou Satellite Navigation System. The BeiDou System Space Signal Interface Control Document (2.0)defines the interface relationship between the satellites of exoteric service signal B1I/B2I and the user terminals, clarifies the coordinate and time system that the BeiDou System uses, regulates the signal structure and basic properties of B1I/B2I, as well as the ranging code, etc, and provides BeiDou Navigation short messages. The publication of this document indicates that BeiDou System has become the first system that owns two civil frequency points and has been able to provide service. Enterprises both home and abroad will be able to develop BeiDou Double-Frequency High Accuracy Receiver on the basis of this document, in order to provide more accurate navigation service.