Question

Hello,

What do the values for begining lattitude=21 and begining longtitde=230E mean (when inputing grid option args for Tecmaps)?What will be happened if mapping region is outside of area limited by above coordinates?

Thanks!

-- PhamHoangLong - 23 Nov 2011

Answer

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Dear PhamHoangLong^?,

Sorry for the delay in answering, you caught us during our Thanksgiving holiday, and there was a small issue with the support site upon our return.

The BeginLat^? and BeginLon^? values are just the defaults. Both items are input on the command line, so the user will specify them. You should not be limited in your mapping region.

Best Regards,

-- Susan Cummins

-- SusanCummins - 30 Nov 2011

Hi Susan Cumminns!

Thanks a lot for your answer. Now i have some more questions, if you know the answers, please explain to me! 1. Is the mapping region limited by the location of the stations or of the IPP (ionospheric pierce points)? For instance, if only one station is used to model a local ionospheric map, then how to determine the size of the ionospheric map?

2. Could the TecMaps be used to map local (regional) ionosphere using 5-6 stations and distances between them are about 800~1000km? In this case, how to determine centre and size of the map? And values DeltaLon^? and DelLat^? are default or can be specified by user??

3. Question about the app Discfix:

• Is it able to correct the appearance "Clockjump" ?
• what does it mean value DCWLFixMaxGap^?=3000 and DCGFFixMaxGap^?=250? How is the quality of the output results depending on changing these above parameters? Need or no need to change the values of these parameters when the length of the observations is diiferent (for example: several hours or one, several days ) to obtain better smoothing results?

4. Will the Diiferential Code Biase (P2-P1) of a dual frequency receiver be changed before and after when that receiver is turned off and turned on again???

5. Need to correct bias (P1C1) if C1 is used to compute slant TEC = P2'-C1 when P1 pseudoranges are absent???

Thanks again!

Best regards!!!

Pham Hoang Long

Dear Pham Hoang Long,

I will inquire locally regarding your questions, however, you may be able to find some answers by downloading the source code if you have not done so already. In the /dev/apps subdirectories, in both the source code files and also sometimes in README files, additional helpful and detailed information may be found regarding capabilities and options, beyond what is provided in the User's Guide.

Regarding DiscFix^?, you may wish to look at the documentation and code in the DiscFix^?.cpp file located in /dev/apps/geomatics/cycleslips.

Regarding TECMaps, I recommend starting with two README files, one under /dev/apps/ionosphere, and one under /dev/apps/ionosphere/example. These two documentation files help clarify the processing for ionosphere applications.

While I pursue specific answers to your questions, I hope you are able to make use of the information located with the source code. I will be in touch later this week.

Best Regards,

-- Susan Cummins

-- SusanCummins - 05 Dec 2011

Dear Susan Cummins,

Thanks so much and I'll follow your advices. I look forward to your reply!

Best Regards,

--Pham Hoang Long

-- PhamHoangLong - 06 Dec 2011

Dear PhamHoangLong^?,

I'm not sure if you've accessed the GPSTk User's Guide, but if not you may wish to consult it for additional information on the applications and their parameters. There is also some introductory text that may be helpful. Also, I recommend looking at the documentation in the header (.hpp) files associated with the applications of interest. The .cpp files can also contain enlightening documentation. In the case of DiscFix^?, you are asking about advanced options which are not usually changed by the user, but if you want to see descriptions of these, they are contained in /dev/lib/geomatics/DiscCorr.cpp. This is the discontinuity corrector software used by DiscFix^?. DiscCorr^?.hpp may also be informative for you.

When the author of this software is available next week, I will see about getting answers to your specific questions 1-5 above.

Best Regards,

-- Susan Cummins

-- SusanCummins - 09 Dec 2011

Dear Susan Cummins

Ok, thanks so much!

--Pham Hoang Long

-- PhamHoangLong - 10 Dec 2011

Best wishes