PrideLab / PRIDE-PPPAR

An open‑source software for Multi-GNSS PPP ambiguity resolution
http://pride.whu.edu.cn/
GNU General Public License v3.0
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PRIDE-PPPAR CAN ONLY PROCESS 5-DAYS MERGED DATASETS #5

Closed Waley04 closed 2 years ago

Waley04 commented 2 years ago

Greetings PrideLab,

Thanks for PRIDE-PPPAR and the effort you have invested in this powerful software.

I was testing the current commit and I noted that it can only process 5-days merged datasets. The modified Julian day span (mjd_span) is limited to 5 days as specified in the pdp3 script. You may consider revising this in order to support continuous solutions for multiple days greater than 5 days.

I tried to modify this option. However, I can only get a continuous solution for 7 days. Exceeding such a batch period fails owing to increased number of parameters.

Thanks for your support.

Thanks with regards,

Waley.

PrideLab commented 2 years ago

Dear Waley, thanks for your advice.

I'm sorry for the inconvenience this has caused you. The PRIDE PPP-AR is designed for processing single-day and short-period observations. One of the reasons is that, as you said, processing a long-time period dataset will impose a substantial computational burden on parameter estimation. Furthermore, under the existing processing strategy, the accuracy of the multi-day solutions will not significantly improve with respect to the single-day solutions except for atmospheric and receiver clock parameters. It is because we have forced the ambiguity parameters of all satellites reset at the day boundary in consideration of the discontinuity of the code/phase biases. Therefore the integer ambiguity constraint can only impose on parameters within a single day.

Would you mind telling us the scientific purpose for which you need to process a long-period dataset? We believe this would be helpful for us to evaluate directions for improving the software.

Waley04 commented 2 years ago

Dear PrideLab,

Many thanks for the clarification.

Purpose of processing long-period datasets :
I needed this in the atmospheric modeling study. Since PRIDE-PPP has the capability to improve the atmospheric solution (e.g ZTD) for a long-period dataset, then this is fine. The current task I have is atmospheric modeling and position modeling for machine guidance and precision agriculture.

Thanks for your support.

Regards,

Waley.

PrideLab commented 2 years ago

Dear PrideLab,

Many thanks for the clarification.

Purpose of processing long-period datasets : I needed this in the atmospheric modeling study. Since PRIDE-PPP has the capability to improve the atmospheric solution (e.g ZTD) for a long-period dataset, then this is fine. The current task I have is atmospheric modeling and position modeling for machine guidance and precision agriculture.

Thanks for your support.

Regards,

Waley.

We managed to increase the maximum number of days for multi-day processing from 5 to 32 with minimal changes to the program structure. It should be noted, however, that PRIDE PPP-AR will take several hours to process consecutive observations of more than 10 days. If you wish to process multi-day observations for a longer timespan, you can try again to modify mjd_span in pdp3.sh, but we cannot guarantee its success for now.

Thank you for your feedback on the software improvements. We will try to further improve its multi-day processing capability in the future.

Waley04 commented 2 years ago

Thanks very much for your timely response and update.

I will try to modify the mjd_span in the pdp3 script. This will assist me to determine the effect of the current multi-day processing span you just extended. If anything I will report.

Once again, thanks for your feedback with kind regards,

Waley.