vary c1 and thrustdirection

General help that does not fall into a more specific category

vary c1 and thrustdirection

Postby Therealrock » Thu Jul 25, 2013 11:14 am

Hi.
Is it posiible to use the thrustdirection and the C1 coefficient in a vary command for a target sequenze, where a rondevousz between to satelites is simulated.
I ask this because when i try it out i get no result. i should mention that it is simulated with finite burns not impulsive burns.

Thanks Franz
Attachments
rondevousgo.script
(12.23 KiB) Downloaded 127 times
Therealrock
 
Posts: 6
Joined: Wed Apr 17, 2013 4:23 pm

Re: vary c1 and thrustdirection

Postby shughes » Thu Jul 25, 2013 1:48 pm

GMAT can solve this problem but there are some issues in the setup. Here are some suggestions:

[list=]
[*] Set ShowProgress to true on your differential corrector so you can debug the configuration. Then you notice that the DC never moves away from the initial guess.
[*] The upper bound is set to the same as the initial guess and the targeter needs to increase C1 but can't.
[*] I doubt the propagation after the maneuver is long enough to drift back to the desired relative location (it is set to 100 seconds). The relative velocities are pretty small so drifting from 10 km to 1 km will take a lot longer. I would expect a much longer drift period. You may want to devise a more complex scripted propagation setup to propagate to the correct conditions when the drift can efficieciently be corrected. This isn't trivial, but it's not that difficult.
[/list]

Hope this helps.
shughes
 
Posts: 443
Joined: Mon Jun 09, 2008 6:27 pm

Re: vary c1 and thrustdirection

Postby Therealrock » Mon Aug 26, 2013 2:01 pm

Thanks a lot for the advice, they helped a lot, but still not working. The sattelites are getting close to eachother but then they are drifting away. Nevertheless thanks for the help.

best regards Franz
Therealrock
 
Posts: 6
Joined: Wed Apr 17, 2013 4:23 pm

Re: vary c1 and thrustdirection

Postby shughes » Wed Sep 18, 2013 3:44 pm

Even after the correct relative displacement is achieved, eliminating relative drift is complex. See this document (http://www.ai-solutions.com/Portals/0/A ... 2001/4.pdf) Appendix 1 and 2 for one approach to handle and read other references listed for more info.
shughes
 
Posts: 443
Joined: Mon Jun 09, 2008 6:27 pm

Re: vary c1 and thrustdirection

Postby donnieronald » Sat Dec 21, 2013 7:53 am

Thanks for the exchange of information.
donnieronald
 
Posts: 1
Joined: Sat Dec 21, 2013 7:52 am


Return to General

Who is online

Users browsing this forum: No registered users and 6 guests

cron