Question

Hello There,

I was trying to obtain elevation and azimuth values using wheresat and igs*.sp3 file. What I got was values from 01:00:00 to 23:00:00 of that day. I see that the sp3 file has data from 00:00:00 of that particular day. What should I do to get the data from the missing hours (00:00 and 23:00).

I tried introducing --start and --end time but it didnt work. Am I going wrong anywhere? sp3 file i used is igs18113.sp3 and I downloaded the latest version of wheresat (1 Oct 2014). any help would be appreciated.

Thank you.

-- SajanMushini1 - 24 Feb 2015

Answer

ALERT! If you answer a question - or have a question you asked answered by someone - please remember to edit the page and set the status to answered. The status is in a drop-down list below the edit box.

This is because of the Lagrange interpolation procedure that usually requires a 10 order polynomial interpolation. Thus, it needs epochs before and after the time you interpolate. If you want you to interpolate for the epoch 01:00 (or 00:00) you need enough epochs before. If you want to interpolate for the epoch 23:00 you need enough epochs after. Are those needed epochs in your file? You should have the answer to your problem if you understood my point. Check the PositionSatStore class to learn more about satellite orbit interpolation: http://www.gpstk.org/doxygen/PositionSatStore_8cpp-source.html

-- OctavianAndrei - 25 Feb 2015

Thank you Andrei for the explanation. And yes, it works fine if previous day and next day files are used.

-- SajanMushini1 - 25 Feb 2015 No such template def TMPL:DEF{PROMPT:supportquery}

Topic revision: r3 - 25 Feb 2015, SajanMushini1
 

This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback