With the rapid development of China's BeiDou Navigation Satellite System (BDS), the application of real-time precise point positioning (RTPPP) based on BDS has become an active research area in the field of Global Navigation Satellite Systems (GNSS). BDS has provided the service of broadcasting RTPPP information. It indicates that BDS has become the second satellite system that provides RTPPP services, following Galileo among the GNSS, but work based on this direction has yet to be explored. Therefore, this paper evaluates the performance of precise point positioning (PPP) service using a software-defined receiver (SDR). An experiment was carried out to verify the feasibility of the SDR. The PPP-B2b signal was processed to obtain PPP service information, including orbit corrections, clock corrections, and differential code bias corrections. The timevarying attributes of these corrections of BDS and GPS are evaluated, and the integrity and stability of the PPP service were analyzed. The results show the PPP-B2b signal can stably provide PPP services for satellites in the Asia-Pacific region, including centimeter to decimeter-level orbit corrections and meter-level clock corrections for BDS satellites. At the same time, PPP services provide decimeter to meter-level orbit correction and meter-level clock correction for GPS satellites. Finally, detection tip for bitstream availability in SDR is proposed. Some content which is not defined in the official document, such as the PPP-B2b frame arrangement, various correction update cycles and the progress of PPP service are discussed. INDEX TERMS Real-time precise point positioning (RTPPP); BeiDou Navigation Satellite System (BDS); Signal processing; Software-defined receiver (SDR). I. INTRODUCTION The development of Chinese BeiDou navigation satellite system (BDS) can be divided into three steps. The first step was to construct the BeiDou Satellite Navigation Demonstration System (BDS-1) [1]. Using an active positioning scheme, the system provided users in China with positioning, timing, wide-area differential and short message communication services. Since 2003, the third BeiDou navigation experiment satellite was launched, further enhancing the performance of the BeiDou Navigation Satellite Demonstration System [2]. The second step was the construction of the BeiDou Satellite Navigation Regional System (BDS-2). In addition to a technical scheme compatible with that of BDS-1, BDS-2 further included a passive positioning scheme, and provided users in the Asia-Pacific region with positioning, velocity measurement, timing, and short message communication