The LM-3A series launch vehicle was used for all launch missions for the BeiDou Navigation Satellite System (BDS) project, including BDS-1, BDS-2, and BDS-3. So it is known as Space Express for BDS. During the 26 years’ development period for the BDS project, a series of key technological breakthroughs with the LM-3A series of launch vehicles were made, improving the launch capability of different payloads into GTO, IGTO and MTO, from sending one satellites into transfer orbit to sending two satellites into transfer orbit, to sending two satellites into target orbit directly. A total of 59 satellites in 44 launches were launched using the LM-3A series launch vehicle for the BDS project, achieving 100% success.

China’s BeiDou Navigation Satellite System (BDS) construction has been completed and the system has been formally commissioned. Most of the Electric Power Systems (EPSs) for MEO satellites were developed by the Shanghai Institute of Space Power-sources. The 42 V medium-voltage fully-regulated high-power EPS has been adopted for the first time in medium Earth orbit, with an output power reaching about 3 kW. Compared with the 42 V medium-voltage semi-regulated bus power system used in the Regional Navigation BDS-2 satellite, the EPS of the BDS-3 MEO satellites has increased power by about 80%, adopting many newly developed products such as high-efficient triple junction GaAs solar cells, high-energy-density lithium ion batteries and a high-efficient autonomous power control unit (PCU). Based on the studies on the medium-voltage fully-regulated and high-power EPS technical principles, and the adaptability and reliability of various working modes, the test verifications for the EPS were conducted both on the ground and in orbit. Compared with other global navigation satellite systems such as GPS, Galileo and GLONASS, the EPS of the BDS-3 MEO satellite has a long design life time which is equivalent to that of the GPS and Galileo, but with a larger power supply capability and power ratio, distinguishing its advancement in the field of satellite power technology.

Satellite laser ranging (SLR) is an unambiguous measurement technique and generates high accuracy satellite orbit data. All satellites in the BeiDou navigation satellite system (BDS) carried laser retro-reflector arrays (LRAs), so they can be tracked by ground SLR stations in order to provide the accurate observation data. The Shanghai astronomical observatory (SHAO) designed the LRAs, and also developed the dedicated SLR systems using a 1 m-aperture telescope and a transportable cabin-based SLR system with a telescopes of 60 cm aperture. These enable BDS satellite ranging during daytime and nighttime with centimeter-level precision, allowing highly accurate estimations of satellite orbits. Moreover, some of the BDS satellites are also equipped with laser time transfer (LTT) payloads, which were developed by the SHAO and China Academy of Space Technology (CAST), providing a highly accurate time comparison between the satellites and ground clocks. This paper describes the dedicated SLR system and the design of the LRAs for BDS satellites, as well as global SLR measurements. The SLR tracking data is used for evaluating the orbit accuracy of BDS satellites and broadcast ephemeris, with an accuracy of less than 1 m. The LTT measurements to BDS satellites for a single shot have a precision of approximately 300 picoseconds, with a time stability of 20 picoseconds in 500 s.

 With the development of satellite navigation technology, the user demands for the integrity of Global Navigation Satellite System (GNSS) have increased more and more. A ground-based monitoring system can hardly report an alarm message to GNSS users during the valid alarming period due to the satellite-Earth propagation delay. It is beneficial to monitor abnormal events and report the corresponding alarms from orbit. Adopting this approach, which is an important feature for future GNSS integrity monitoring, the time needed to provide an alarm is shorter and the system integrity capability is strengthened. The BeiDou Navigation Satellite System (BDS) new generation satellites have the capabilities of satellite autonomous integrity monitoring (SAIM). This paper presents the technical scheme of SAIM, and proposes the integrity monitoring method of both navigation signals and the clocks onboard. The proposed method was verified through the onboard test on the BDS satellites. In addition, we analyzed the integrity telemetry data from the new generation of BDS satellite, including signal delay, power, carrier phase measurement, correlation peak, consistency of pseudo-code and carrier phase, clock phase and frequency step. The analysis results indicated that the quality of the data on orbit met the requirements, and SAIM could monitor effectively any abnormal change of satellite clocks and navigation signal, generate rapidly an alarm message, and transmit it to the user. The alarm time was less than 6 s through the message, and 2 s through non-standard code (NSC). Finally, we present future opportunities for improving the SAIM technology of BDS.

The transportation industry is one of the largest users of the BeiDou Navigation Satellite System (BDS), characterized by multiple locations, long lines, wide range, and extensive mobility. The application of BDS in the transportation industry improves the development level of intelligent, safe, green and shared transportation. Based on the introduction of the application requirements and characteristics of BDS in the transportation industry, this paper systematically introduces the overall status of BDS in the transportation industry, covering highways, waterways, railways, civil aviation, and the postal service. Finally, the paper forecasts future applications of BDS in the field of transportation. It identifies within the transportation industry rich application scenarios for the cultivation of advanced technologies represented by BDS, enhancing transportation safety services and guaranteeing emergency communication, while improving the operation efficiency and management level of an integrated transportation system.

The United States was the first country in the world to develop a satellite navigation system, with rich experience in system management, R&D, operation, and satellite applications industry. It started the construction of the Global Positioning System (GPS) in 1973 and deployed the first satellite in 1978. It has successfully developed and deployed three series of GPS satellites with a total of seven models. The United States is now focusing on the research and development of cutting edge navigation technologies and constellation modernization, replacing old ones with new GPS III series of satellites and actively exploring and verifying the frontier navigation technologies represented through the Navigation Technology Satellite 3 (NTS-3). It is now upgrading the original ground-based operation and control system, actively developing and deploying the GPS Next Generation Operational Control System (GPS OCX), and upgrading the military user equipment supporting Military Code (M-Code). The U.S. attaches importance to multiple measures to improve the service performance of the GPS system and enhance the resilience of the system to provide positioning, navigation, and timing capabilities. In this context, the progress of the construction of GPS and the related technological innovations are separated out and analyzed, which will help the Global Navigation Satellite System (GNSS) solutions summarizing their experience and learning from each other’s development to better serve social progress and economic development.