Estimating satellite and receiver differential code bias using a relative Global Positioning System network

Elghazouly, Alaa A.; Doma, Mohamed I.; Sedeek, Ahmed A.

doi:https://doi.org/10.5194/angeo-37-1039-2019

Articles | Volume 37, issue 6

https://doi.org/10.5194/angeo-37-1039-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Vertical coupling in the atmosphere–ionosphere system

https://doi.org/10.5194/angeo-37-1039-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 37, issue 6

Regular paper

|

18 Nov 2019

Regular paper |

| 18 Nov 2019

Estimating satellite and receiver differential code bias using a relative Global Positioning System network

Alaa A. Elghazouly, Mohamed I. Doma, and Ahmed A. Sedeek

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Final revised paper (published on 18 Nov 2019)
Preprint (discussion started on 03 Dec 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review of "Estimating Satellite and Receiver Differential Code Bias Using Relative GPS Network" by Alaa el ta.', Anonymous Referee #1, 09 Dec 2018
- AC1: 'Authors response on Anonymous Referee #1 comments', Alaa Elghazouly, 10 Dec 2018
AC2: 'Paper Withdraw', Alaa Elghazouly, 22 Feb 2019
RC2: 'Comment on “Estimating Satellite and Receiver Differential Code Bias Using Relative GPS Network” (by Alaa A. Elghazouly, Mohamed I. Doma, Ahmed A. Sedeek)', Anonymous Referee #2, 08 May 2019
- AC3: 'Authors response on Anonymous Referee #2 comments', Alaa Elghazouly, 27 May 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reject (05 Mar 2019) by Christina Arras

ED: Reconsider after major revisions (further review by editor and referees) (28 May 2019) by Christina Arras

AR by Alaa Elghazouly on behalf of the Authors (28 May 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (29 May 2019) by Christina Arras

RR by Anonymous Referee #3 (19 Jul 2019)

RR by Anonymous Referee #4 (26 Jul 2019)

Suggestions for revision or reasons for rejection

This paper reports estimation of receiver and satellite Differential Code Biasis (DCBs) for Global Navigation System (GNSS) to obtain absolute value of Total Electron Content (TEC). Nowadays, GNSS is widely used for studies of the ionosphere. Therefore, this kinds of study is important and could contribute to the ionospheric studies. However, in this manuscript, interpretation and discussion based on the results are not enough. This paper cannot be accepted in publication.

The authors have compared DCBs estimated by different methods, such as MSDCBE, M_DCG, and ZDDCBE, and provided by CODE, IGS, and JPL. The difference between them are shown, but the reasons why the difference is large (or small) is not discussed based on the difference of the adopted methods.

Specific points:

-- ll. 16, 17: In Abstract, the authors describe
"The second factor concerned with estimating DCBs using single GPS Station Precise Point Positioning (PPP) or using GPS network."
However, the results are not shown in this manuscript.

-- l. 131, "By substituting eq (10) and eq (11) into eq (9) we get":
Equation (8) is also needed.

-- l. 147: Explain how constants of 0.05 and 0.02 are determined.
-- l. 150: Explain how constants of 5 and 2 cm are determined.

-- l. 150: "c" is used as speed of light. Use another expression.

-- DCBs estimated in this study are compared with those obtained from CODE or IGS. The authors consider that smaller difference from DCBs estimated by CODE and/or IGS is better. In this paper, the authors show that MSDCBE with a weighting function depending on the satellite elevation angle is better than M_DCB without weighting function.

-- Is MSDCBE same as M_DCB except only usage of weighting function? The authors concluded that the estimated DCBs are affected an improved by using weighting function according to the satellite elevation angle. To obtain this conclusion, MSDCBE must be same as M_DCB except only usage of weighting function.

-- The authors describe "improved" in conclusion, but the correct value of DCBs are unknown. The estimated results becomes close to the those from IGS and CODE by using a weighting function, but it is impossible to conclude "improved".

-- The authors need to compare the method of MSDCBE with that used by IGS and CODE, and discuss the difference among the methods. Especially, the authors need to mention whether the methods adopted by IGS and CODE use a weighting function or not. If they use the same weighting function, the results shown in this manuscript is meaningless.

-- l. 213: What is the difference of ZDDCBE compared to other methods?

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ED: Reconsider after major revisions (further review by editor and referees) (05 Aug 2019) by Christina Arras

AR by Alaa Elghazouly on behalf of the Authors (30 Aug 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (13 Sep 2019) by Christina Arras

RR by Anonymous Referee #4 (23 Sep 2019)

RR by Anonymous Referee #3 (01 Oct 2019)

ED: Publish subject to minor revisions (review by editor) (01 Oct 2019) by Christina Arras

AR by Alaa Elghazouly on behalf of the Authors (01 Oct 2019) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (02 Oct 2019) by Christina Arras

AR by Alaa Elghazouly on behalf of the Authors (02 Oct 2019) Author's response Manuscript

ED: Publish as is (08 Oct 2019) by Christina Arras

Short summary

Receiver and satellite differential code biases (DCBs) are one of the main error sources in estimating precise global ionosphere maps (GIMs) from Global Positioning System (GPS) data. This paper introduces a mathematical model for estimating satellite and receiver DCBs from a GPS network written in the MATLAB environment. Our code was tested and compared with Ionosphere Associated Analysis Centers (IAAC) and other researchers' code results. The results show an improvement for estimated DCBs.