中文
The BeiDou Navigation Satellite System (BDS) is China’s satellite-based navigation system. It provides all-weather and all-day positioning, navigation, and timing services to its users. Since the completion of the first and second phase of the system – BDS I and BDS II - BeiDou has been widely used in China and the Asia-Pacific region. The development work on BeiDou phase 3 started 2013, and will extend BeiDou passive PNT service coverage from Asia to the whole world by approximately 2020.
The third phase of BeiDou (BDS III) is planned to contain 30 satellites; 3 GEO, 3 IGSO, and 24 MEO satellites. Signals are designed to be compatible and interoperable with other global navigation satellite systems (GNSS). This implies that BDS III will be further integrated into the international GNSS family to provide worldwide users with better services by jointly using BDS III and other GNSS.
In 2017, BDS-related industrial activity contributed 40% of the overall output value of China’s ¥250 billion worth of satellite navigation and positioning services. With further development of the constellation, an increased demand on receivers, device integrators, and test solution/services etc. can be foreseen.
The diagram below shows all BeiDou signals which are currently operational. The new BDS III signals will use the same carrier frequencies as the GPS and Galileo systems, so chipset manufacturers and device developers will need to test integrated designs to avoid problems caused by confusing data from different GNSS.
BeiDou phase 3 (BDS III) signals are now available on Spirent’s GSS7000 and GSS9000 simulators:
Signals B1C, B2a and B3I have been implemented to their official ICD documents:
BeiDou Navigation Satellite System SISICD Open Service Signals Version 1.0, December 2017, for B1C and B2a.
BeiDou Navigation Satellite System SISICD Open Service Signals Version 1.0, February 2018, for B3I.
Legacy signals such as B1I and B2I are still supported to their most up to date ICD (BeiDou Navigation Satellite System SISICD Open Service Signals Version 2.0, December 2013, for B1I and B2I).
Spirent’s PosApp software is capable of simulating 63 BeiDou satellites simultaneously, with 63 different PRN sequences. PRN sequence from 38-63 is the extended constellation, and is supported on Spirent’s simulators. Chip developers and integrators could benefit greatly from testing with the extended constellation.
As can be seen from the figure below, with Spirent simulators, B1I and B2I signals are broadcast from satellites 1-30; PRN sequence 1-37 B1C and B2a signals are broadcast from satellites 6-58; and PRN sequence 1-63 B3I signals are broadcast from satellites 1-63.
Satellites 1-5 and 59-63 can be freely setup as GEO, IGSO or MEO. Satellites 6-58 can be freely setup as IGSO or MEO.
All simulated BDS signals (B1I, B2I, B3I, B1C and B2a) can be successfully tracked by a BeiDou receiver. A location fix is achieved in the simulation, as illustrated below.
To evaluate the performance of the receiver or any device under test, discrepancy between the simulated ‘truth data’ and the data generated by the receiver is calculated by Spirent positioning software.
By testing with the new BDS III signals on a Spirent simulator, you can assure your designs work well before the real systems are fully operational, and can continue to test them with a robust methodology into the future because of Spirent’s promise to continually review and update SIS-ICDs as they are changed.
