Radio determination satellite service (RDSS) is one of the characteristic services of Beidou navigation satellite system (BDS), and also distinguishes with other GNSS systems. BDS-3 RDSS adopts new signals, which is compatible with BDS-2 RDSS signals in order to guarantee the services of old users. Moreover, the new signals also separate civil signals and military signals which are modulated on different carriers to improve their isolation and RDSS service performance. Timing is an important part of RDSS service, which has been widely used in the field of the power, transportation, marine and others. Therefore, the timing accuracy, availability and continuity is an important guarantee for RDSS service. This paper summarizes the principle of one-way and two-way timing, and provides the evaluation method of RDSS timing accuracy, availability and continuity. Based on BDS-3 RDSS signal measurements of system, the performance of one-way timing and two-way timing is analyzed and evaluated for the first time. The results show that: (1) the accuracy of one-way timing and two-way timing is better than 30 ns and 8 ns respectively, which are better than the official claimed accuracy; (2) the RMS of one-way timing accuracy is 5.45 ns, which is 20% smaller than BDS-2, and the availability and continuity are 100%; (3) the RMS of two-way timing accuracy is 3.59 ns, which is 34% smaller than one-way timing, and both of the availability and continuity are 100%; (4) the orbit maneuver of GEO satellite make the one-way timing has 7.68 h recovery, but has no affection on the two-way timing.

The Arctic region holds immense strategic value in terms of scientific expedition, maritime transportation, and resource development, which makes reliable and secure satellite navigation services in this area crucial. This study first calculates and analyzes key performance indicators of BeiDou System (BDS). These indicators include the number of visible satellites, Position Dilution of Precision (PDOP) values, and observation elevation angles at typical monitoring points in the Arctic region. To improve BDS’s coverage capabilities and further enhance its contribution to global satellite navigation in the Arctic region, two methods are proposed in this paper: (1) to introduce regional services such as PPP, SABS and a regional short message service to BDS Inclined Geosynchronous Orbit (IGSO) satellites and (2) to increase the inclination angle of BDS IGSO satellites to 60 degrees. A comparative analysis between the proposed design and the existing system was conducted. The results show that: (1) utilizing IGSO satellites for regional services can significantly improve coverage in the Arctic region, and (2) adjusting the IGSO satellite inclination to 60 degrees could enhance the performance of BDS’s Radio Navigation Satellite Service (RNSS) and other regional services.