GNSS ultra-rapid orbit and clock offset estimation method with the aid of the constraint of BDS-3 onboard clock

The high-stability BDS-3 onboard clock is one of the significant advanced technologies of BDS, which is underutilized in GNSS data processing. To solve the precision restriction of GNSS ultra-rapid orbit and clock offset parameters under the strict timeliness limitation, GNSS ultra-rapid orbit and clock offset estimation method with the aid of the constraint of BDS-3 onboard clock is proposed in this research. Firstly, based on the correlation GNSS clock offset and orbit, the GNSS orbit determination model is constructed with the consideration of BDS-3 onboard clock parameter. Secondly, impacts of onboard clock constraints on GNSS orbit determination are analyzed by taking BDS-3 precise clock offsets as example in experiments. Thirdly, to overcome the influence of the prediction clock offset and selected constraints on GNSS ultra-rapid orbit determination, the synchronously processed method of BDS-3 clock modelling and GNSS ultra-rapid orbit estimation is proposed. According to the experimental results, it is indicated that the accuracy of BDS-3 and GPS orbit and clock offsets can be respectively improved with 27. 5% , 5.1% and 20. 2% , 5. 2% , under the optimal constraint on BDS-3 onboard clock. Meanwhile, compared with the traditional epoch-wise white noise strategy of GNSS clock parameter, the proposed one-step processing method for BDS-3 satellite clock modeling and GNSS ultra-rapid orbit determination can respectively improve the accuracy of GNSS ultra-rapid clock offset and orbit up to 4. 8% and 34. 2%, where the millimeter-level orbit accuracy improvements can be obtained. Therefore, the proposed GNSS ultra-rapid orbit and clock offset estimation method based on BDS-3 clock offset constraints can effectively utilize the information of BDS-3 highly stable onboard clock information, and realize the accuracy improvement of GNSS ultra-rapid orbit and clock offsets. © 2024 SinoMaps Press. All rights reserved.