[IGSMAIL-8409] All-frequency phase bias products and PRIDE PPP-AR Ver. 3.0 for day-boundary continuities

[Jianghui Geng]

Dear all,

Happy new year!

We are pleased to announce that ALL-frequency rapid code/phase bias products (i.e., WUM0MGXRAP) for GPS, Galileo, BDS-2 and BDS-3 have been released at IGN (since week 2290 on ftp://igs.ign.fr/pub/igs/products/mgex/ <ftp://igs.ign.fr/pub/igs//products/mgex/>) and Wuhan (since day 001 of 2023 on ftp://igs.gnsswhu.cn/pub/whu/phasebias). The latency is less than 18 hours normally (Note: dual-frequency WUM0MGXRAP product is faster at a latency of about 11 hours, but updated only on Wuhan FTP). CDDIS is also updating them, but at a longer latency of up to a few weeks at the moment (https://cddis.nasa.gov/archive/gps/products/). “All-frequency” means to enable PPP ambiguity resolution (PPP-AR) at any frequency choices and observable combinations (e.g., even GPS L1/L5 PPP-AR in the case of inter-frequency time-variable clock biases).

This WUM0MGXRAP product contains: a 30-s satellite clock file with the 24:00 epoch especially, fully aligned with the IGS legacy clock, but with integer nature; a bias-SINEX file with daily code/phase OSBs for all frequency bands except for the 15-min GPS Block IIF L5 and BDS-2 B2I phase biases; as well as the 5-min orbit, 30-s satellite attitude quaternion and daily ERP files. All antenna phase centers have been applied to the bias generation (i.e., APC_MODEL).

Satellite clocks plus code/phase biases have been aligned precisely across days for all frequencies on account of orbit discontinuities. This means that day-boundary discontinuities for GPS, Galileo, BDS-2 and BDS-3 products have been minimized to the smallest since 2023 thanks to our keeping integer continuity of undifferenced ambiguities for all frequencies from day to day. This would benefit kinematic positioning and time/frequency transfer across days, no matter which frequency choices. Users would not need to calibrate day-boundary discontinuities anymore at their own side.

Simultaneously, we have upgraded the open-source software PRIDE PPP-AR to version 3.0 at https://github.com/PrideLab/PRIDE-PPPAR. This version supports the all-frequency PPP-AR functionality for any two eligible frequency choices (e.g., GPS L1/L5, Galileo E1/E6, BDS-2 B1I/B2I, BDS-3 B1C/B2a, etc.). LEO kinematic orbit determination is also enabled for GRACE particularly. The positioning and orbit precisions are state-of-the-art compared to IGS and relevant official institutions. In addition, PRIDE PPP-AR results are expected to be free from any day-boundary discontinuities for kinematic positions and time transfer when multi-day processing of up to 108 days is enabled, especially when BDS-2 is excluded.

Please do not hesitate to contact us (pride at whu.edu.cn <mailto:pride at whu.edu.cn>) if you encounter any problem with the WUM0MGXRAP product or the PRIDE PPP-AR software. This work is funded by National Science Foundation of China (No. 42025401) and under the auspices of IAG Sub-Commission 4.2 “Multi-constellation and multi-frequency GNSS” and IGS Pilot Project PPP-AR (https://igs.org/wg/ppp-ar/#rapid).

Best regards,
Jianghui Geng on behalf of the PRIDE Group including Qiyuan Zhang, Jihang Lin, Jing Zeng and Wenyi Li who have contributed	the most.

Professor in GNSS Geodesy
GNSS Research Center, Wuhan University
Email: jgeng at whu.edu.cn
Office: +86 (0)27 68778955
Mobile: +86 17762578656
Homepage: http://pride.whu.edu.cn

Earn the right to be wrong

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