GPS, BDS-3, and Galileo Inter-Frequency Clock Bias Deviation Time-Varying Characteristics and Positioning Performance Analysis
Round 1
Reviewer 1 Report
Comments for remotesensing-1839158
GPS, BDS-3, Galileo inter-frequency clock bias deviation time-varying characteristics and positioning performance analysis
This paper focuses on the estimation of uncombined inter-frequency clock bias (IFCB) of GPS, BDS-3 and Galileo, and analyze the time-varying characteristics and short-term stability of IFCB, as well as its influence on the positioning of GPS, BDS-3 and Galileo PPP.
The manuscript is well organized and presented. The Figures and Tables give pertinent information. Some details need to be clarified in the manuscript to help better understand the results.
1. Overall, it seems that font of the characters in the formula is larger than that of the main text, which looks inharmonious.
2. Page 6, the first paragraph of Sec. 3.1:
‘In this work, the PCO and PCV of GPS Block IIF satellite are corrected with the PCO and PCV of only L2, because the PCO and PCV of the L5 frequency are not available. In addition, since the frequencies between L2 and L5 are closer, the receiver PCO and PCV of L2 are used to correct the L5.’
The PCO and PCVs of GPS BLOCK IIF at L1 are not corrected? How to correct the PCO and PCVs of BDS and Galileo satellites?
3. In the triple-frequency PPP validation, the IFCB are corrected in the function model, how do you deal with the IFB? Would the processing strategy affect the positioning results?
4. In Figure 2 and Figure 4, the IFCB time series of GPS satellite has obvious periodicity, how is the GPS IFCB modeled over one day to correct the phase observations in the triple-frequency PPP model? would this periodic phenomenon affect the PPP results?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review of the paper “GPS, BDS-3, Galileo inter-frequency clock bias deviation time-varying characteristics and positioning performance analysis”
General thoughts
The article presented research based on GNSS signals from 3 systems for a inter-frequency clock bias deviation time-varying characteristics and positioning performance analysis. The following detailed comments are intended to correct some of the shortcomings of the article. By following these comments and making corrections, the quality of the article will increase and it will be possible to publish.
Detailed comments
1. Authors should very clearly state why they did not used GLONASS signals
2. Authors have to unify font and formatting of the text according to the instruction for authors.
3. In the Introduction chapter, the purpose of the article should be clearly stated and references list extended, especially including research using signals from 4 GNSS systems, I recommend:
¾ Li W et al. (2021) Assessment of multi-GNSS precise orbit and clock products from different analysis centers based on precise point positioning. Acta Geodyn Geomater 18(3):387–397. https://doi.org/10.13168/agg.2021.0027
¾ Lyu D et al. (2020) Real-time clock comparison and monitoring with multi-GNSS precise point positioning: GPS, GLONASS and Galileo. Adv Sp Res 65(1):560–571. https://doi.org/10.1016/j.asr.2019.10.029
¾ Ai Q et al. (2021) Characteristics of Onefold Clocks of GPS, Galileo, BeiDou and GLONASS Systems. Sensors 21(7):2396. https://doi.org/10.3390/s21072396
¾ Zhou W et al. (2022) Multi-GNSS Combined Orbit and Clock Solutions at iGMAS. Sensors 22(2). https://doi.org/10.3390/s22020457
4. What kind of software authors used? It was your own determination of the coordinates based on the, e.g. C++? Please very clearly state if the text
5. There is many similar publications regarding inter-frequency biases in the multi-GNSS observations. Please very clearly state what is new in your idea?
After authors’ improvements text will be accepted for a publication.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
accepted
