Assessment of the Algorithm for Single Frequency Precise Point Positioning at Different Latitudes and with Distinct Magnetic Storm Conditions
Round 1
Reviewer 1 Report
Attachment
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer,
First of all, we thank you for your psitive and constructive comments and suggestions. The changes to the manuscript, please see the attachment.
Kind regards,
Ren Wang
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments to the 1. Introduction.
Line 40: "The atmosphere can be roughly divided into two parts, ..." - This sentence is not correct, or at least not precise. The atmosphere structure may be described taking into account various parameters, for example refractivity.
Line 43: "This can result in distance errors for GNSS satellite users who require high precision measurements" - unclear formulation!
Line 49: ". . . service (IGS) announced . . " - GIMs are already provided.
Line 59: The word "constraint" in wrong place in the sentence. (perhaps: constraint through global ionosphere maps).
Line 60: "apply"?
Line 67: "use GIM constraint on single frequency PPP" - on?
Line 89: "PPP under atmospheric-constrained" - ?
2. Methods
Line 90: "Methods" - Methodology would be more appropriate?
Line 91: What it is "original pseudo range"? Equations (1) and (2) can not be find in the reference [25].
Line 93: "... influence of SF PPP on positioning accuracy" Grammar?
Equations (1) and (2): the second subscript (l) is not explained. Do you mean the first frequency?
Line 97: "x indicated the receiver position increment vector relative to the previous position" - This formulation is in general not proper. It is a special case (you write about it later).
Line 100: "is the frequency dependent receiver uncalibrated code delay" - may be written more clear, e.g. "inter-frequency code bias", "inter-frequency carier-phase bias". Please consider this suggestion.
Line 104: "virtual observation". In the adjustment calculations it is described as "pseudo-observation equation"!
Line 107: ". . . is calculated on the GIM products and the ionosphere pierce point" - It is not on the of IPP (Language?)
Line 119: "The method estimates the state of the next moment" - sorry, but it is nonsense. ("state of the next moment" - Language problems?)
Line 124: "where Z is the observation vector . . . of . . . raw observations" -> perhaps ". . Z is the vector of measurements . .?
Line 124: ". . ., equation (7) can be written as" - it is not correct description. The equation (8) is not derived from the (7).
Line 130: "According to the mathematical functions above, the form of state parameter vector . . ." - "form"? Please correct.
Line 124: "H denotes the matrix of the state parameter vector" - H is design (configuration) matrix.
Line 125: consider: vector X represents the parameters.
Line 126: "covariance R" -> covariance matrix.
Line 133: "Next, the extend Kalman filter" - extend or extended?
Line 133: Please explain why the Extended KF is used?
Line 134: "state function" - not function but . . .?
Line 136: "state transfer matrix" - better "transition matrix"
3. Data sets and processing strategies
Line 152: "the GPS constellation and L1 . . " - Language, the word "and". It is not logical "GPS and L1". The sentence must be corrected.
Line 154: "are derived from" - not "derived" but "taken", or . . .
Line 155: "correction is based . . . . released . . ." - not "based" but . . ., and not "realized" but . . .
Please check/correct English language.
4. Results and discussion
Line 194: English language
Line 232: ". . . are counted." - Word "counted" -> estimated? or . .
Line 237: ". . . the global station is divided into three . . ." ?
Line 259: ". . . lower than the threshold at the 68% level," -> below the threshold level of. - consider it, please.
Line 291: "The rules in Table . . " -> rules?
Line 293: ". . reduced activity of the ionosphere in the midlatitude region" - not precise formulation. In middle latitudes influence of the ionosphere is moderate or low . . . . . Please consider more precise formulation.
Line 303-304: "the stations distributed in the high latitude area are less then the low latitudes" - English language.
5. Conclusions
Line 326: "This paper studies the effects SF PPP . . . on the convergence time . . . ." -> "effects of SF PPP" - wrong description. Please describe it in a proper way.
Line 336: "areas" instead of "area".
Line 336: "After making statistic" - Language!
Line 338: "Since the ionosphere is less active in the . . . region" - not precise description (see above). Consider correction, please.
Author Response
Dear Reviewer,
First of all, we thank you for your psitive and constructive comments and suggestions. The changes to the manuscript, please see the attachment.
Kind regards,
Ren Wang
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors
I attach to this review a file with my comments. I suggest also to make an overall reading and improving of the English and clarity of your work.
Please also do not write the conclusion as a numbered list (1,2,3). Better to write a whole paragraph.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer,
First of all, we thank you for your psitive and constructive comments and suggestions. The changes to the manuscript, please see the attachment.
Kind regards,
Ren Wang
Author Response File: Author Response.pdf
