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Solving Control Parmeter
Posted by sadiq-muhammed on April 3, 2021 at 6:57 amIs the processor program for the Rinex files you can choose all the satellite frequencies (l1,l2,l5,L5/B3…..etc.) or is the automatic option choosing the best frequencies for correction?
Example
Solving Control Parmeter
Interval time : 10
Solve Model: L5/B3
IonoFree Distance[m]: 10000.00
RMSThreshold: 0.04
Ratio Limit Value: 3.0
E-Cutoff 20
Troposphere Model: SAATAMOINEN
Ionosphere Model: KLOBUCHAR
Ephemeris Type: Broadcast Ephemerissadiq-muhammed replied 2 years, 12 months ago 2 Members · 6 Replies- 6 Replies
Not having processed non-GPS data, I do not know why your parameters opt to solve for an L5 and B3 combination. I am assuming B3 is a Beidou frequency. Your image shows ??L2? which should not be a preferred single frequency solution.
in general, an iono-free solution combines data observed at different frequencies to cancel effects due to the ionosphere.
I assume one uses all GNSS satellites in view to take advantage of additional data. I do not know whether interoperability issues between Beidou and GPS have been resolved and implemented e.g. clock standards, reference frame issues.
Looking at your other parameters, I note a 10-second epoch interval which would not do well with 15-second collected data. The processor has to sync observations to a common interval. Many continuously operating sites use a 30-second interval.
I assume the 10 km iono-free distance indicates that solution type should not be used for baselines longer than 10 km. That reminds me of early 1990??s Leica software. Too conservative for most modern software.
Elevation cut-off of 20 degrees might be used at obstructed sites but 15 degrees (or even 10) is generally recommended.
The choice of tropo models is important die to their impact on heighting. Saastamoinen is often a default.
Unless there is a time constraint, I always recommend using IGS orbits rather than broadcast.
Having gone on too long, I stop. Awaiting correction and enlightenment…
Thank you very much, dear brother.
Do I understand the following from you
1- Use an iono-free solution for lines less than 10 km What about the lines that are greater than 10 km to 25 km?
2- Use Interval time: 30
3- The attachment to the image is a baseline correction The RMS values show whether they are acceptableCan I get resources to learn these things?
As I am unfamiliar with the GNSS processing software you are using, I can only provide generic guidance.
I note that I had forgotten to address the Klobuchar ionospheric model. This model is intended for use when dealing with single-frequency data.
See: https://gssc.esa.int/navipedia/index.php/Klobuchar_Ionospheric_Model
A reason for having the GNSS satellites broadcast at different frequencies is to allow for the correction for ionospheric effects on the signal. Modeling is not as good as using multiple frequencies.
In general, an iono-free solution is preferred in all cases with the possible exception of short 5-10 km baselines. On baselines that short it is possible that a better solution can be obtained with single frequency data as the combination of frequencies leads to greater noise.
When I processed data I would process both type solutions and opt for the single frequency if the residual plots showed significant improvement.
Your item 1 misinterpreted my prior reply. I will make a categorical statement: Use iono-free solutions when processing dual frequency data. For baselines less than 10 km a single-frequency solution may be appropriate if residual plots or statistics indicate a better result.
The data collection interval should be based on the interval used at the base stations you use. If you are processing using IGS or other sites use the epoch interval at these sites.
I note that your image shows both float and fixed solution statistics. You should always want a fixed-integer solution. The integer bias ambiguity is solved at each site to each satellite observed. My favorite graphic to explain integer bias ambiguity is here:
My experience with commercial GNSS processing software is limited. Some provide the ability to plot baseline residuals. These plots should be examined to identify possibly wrongly fixed integers and excessive noise. Overall statistics can hide problems.
I recollect helping a colleague using a commercial package that showed good statistics but poor agreement with previous surveys. Looking at the plots we saw a number of uncorrected cycle slips. We were able to delete some data and reprocess. Problem solved.
I encourage you to find your software??s documentation. Many companies post these documents for free download.
I would carefully examine the recommended settings in the documentation. I would process data from continuously operating sites and compare results with known values. Be sure to account for datum and epoch issues. The US CORS network of sites provide the opportunity to test various baseline lengths.
I hope this is responsive.
Good luck with your work.
DMM
Thank you very much, dear brother
Brother, I understand from you that treatment can be used with
Klobuchar for single-frequency data or none
but my gnss device Multi-frequency
My GNSS processing software only has a Klobuchar Ionospheric Model optionOr it is preferable to try other programs to compare results
I have a leica infinity and am trying to work on it but it asks me to specify what kind of receiver I have(calibration new antenna) .
Can I have a program for processing file rinex with which I can compare the results?
Thank you from the heart
I am NOT familiar with Leica Infinity software. I saw this video on YouTube that ma be helpful:
https://www.youtube.com/watch?v=pxLtkbwFHdw
The parameters he uses differ from those you show.
I captured the following from the presentation
hope this helps.
I noticed in your post that you use a 20deg elev mask and also process using the Broadcast Ephemeris. I process using 15 degrees and IGS Rapid Orbits. https://www.igs.org/products/#precise_orbits
DMM
Thank you very much, dear brother
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