DPOS time span and RMS error issues

jcorax

New Member
I have processed some data through DPOS and I am getting some persistent errors/problems.

1) the time span reported by DPOS is always shorter than what I actually recorded. For a few points in this current dataset instead of reading 20 minutes the time span in the DPOS report says 1 minute (note: the jps file size is consistent with a jps file of 15-20 minutes).

2) Also for the same points (reading a 1 minute time span) the RMS value reported is 0.000 (residuals are blank).

I have attached one of these jps files. What could be going on? Why do my reports always read a shorter time span than what was actually collected? Why do these particular reports show a 1 minute time span and a 0 RMS?
 

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Alexey Razumovsky

Well-Known Member
Staff member
5PLS
DPOS report for Cliff3.jps shows time span 11 min and very good RMS. Be aware that DPOS session time is above GPS midnight (next day after data capturing). I guess that you used to submit files too early.
 

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jcorax

New Member
Looks like that is the case when it is submitted individually. Attached are two processing reports done several months apart. The results are consistent and different than if the points are submitted one at a time.

It is my understanding that the points are processed separately and there should be no difference if they are submitted singly or as a group. Am I incorrect in this assumption?

Note: The data were first processed about a week after they were collected, the 24 hour wait period should not have been a factor.
 

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jcorax

New Member
Also what is the "report coordinate system field" asking for? Is it asking what coordinate system set the receiver to (if different than WGS84)?

I have been unable to find one, is there a manual for DPOS?
 

Alexey Razumovsky

Well-Known Member
Staff member
5PLS
Looks like that is the case when it is submitted individually. Attached are two processing reports done several months apart. The results are consistent and different than if the points are submitted one at a time.

The results in attached processing reports (from 08/18/2018 and 12/19/2018) are identical.

It is my understanding that the points are processed separately and there should be no difference if they are submitted singly or as a group. Am I incorrect in this assumption?
Files processed separately and in group may bring different results. The only reason is CORS stations data. DPOS is searching closest CORS stations data using location and date of first coming file.
 

Alexey Razumovsky

Well-Known Member
Staff member
5PLS
Also what is the "report coordinate system field" asking for? Is it asking what coordinate system set the receiver to (if different than WGS84)?
False indication in "report coordinate system field" leads to loss correct SPC coordinate transformation. In your case type "AK_5" or something like this.

I have been unable to find one, is there a manual for DPOS?
No manual
 

Matt Johnson

Well-Known Member
5PLS
It appears the problem occurs when multiple files from different dates are submitted together. A solution is only being provided for the files on the 1st date because data for the second date is not being downloaded:

1545231584612.png
 

jcorax

New Member
No manual
Thank you for your replies. Could you please clarify what should be entered into the "report coordinate system" field. I think you are saying that the local State Plane Coordinate system should be entered?

You mention entering "AK_5", I assume I am correct interpreting this as AK Stateplane Zone 5. What formats does this field accept? It does not seem to be limited to SPC, I have experimented with entering different EPSG codes and it does accept those but I don't exactly understand the changes to the results when I do. Basically I don't know what your software will use that data input field for therefore I don't know what I should enter there.

Would a particular section of the Justin manual be helpful to me in understanding some of these DPOS specific data input fields?
 

jcorax

New Member
It appears the problem occurs when multiple files from different dates are submitted together. A solution is only being provided for the files on the 1st date because data for the second date is not being downloaded:

View attachment 8114
Thanks very much. This answers my question. I collected all the data points in the same day for me, however they do span 2 GPS days. This raises some related questions.

It appears that all my files get slightly different (better?) solutions when submitted one at a time for processing. Since the same CORS stations are used for both solutions (single and group) it seems like the software must be choosing some generalized observations (in terms of time of day) for the grouped solutions and a more specific/appropriate time period for the solutions submitted singly. Does this seem like a correct observation of what is happening?

Since I had no way of knowing in advance this particular limitation of the software/DPOS system it raises concerns for me about what else I do not know. I have downloaded the Justin manual to review, I assume that will help. Do you have any other recommendations for knowledge about DPOS?

Much appreciated!
 
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