Timeline for Simplified WGS84 or EGM2008 model for rapid computations?
Current License: CC BY-SA 4.0
11 events
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| Oct 22, 2020 at 21:01 | history | edited | SE - stop firing the good guys |
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| Jul 16, 2020 at 6:06 | answer | added | Team Amentum | timeline score: 2 | |
| Oct 4, 2018 at 16:34 | comment | added | Christopher Ison | @DuffBeerBaron: Yes, to all three questions, both code and approximate formulation that is widely accepted as approximating WGS 84. However, my more immediate need is just an analytic approximation of the low degree-order field. In re-reading chapter 3 of Regan's book, Dynamics of Atmospheric Re-Entry, he gives a way to approximate that looks satisfactory. I was trying not to have to reinvent it. Also, Regan is using coefficients that are no longer compliant with the updated WGS 84 standard, something I expect that I must fix myself. | |
| Oct 3, 2018 at 14:06 | comment | added | DuffBeerBaron | I'm not sure of exactly what you're looking for.... Are you looking for code that implements the spherical harmonics? Are you looking for an analytic approximation of a low degree/order field? Or are you simply just looking for a truncated set of coefficients, as @uhoh asked? There are options for all of these. | |
| Sep 27, 2018 at 20:17 | comment | added | Christopher Ison | Yes, I looked at geographiclib and thought about making a wrapper for it. However, for my immediate purposes geographiclib as is would be overkill. (Nevertheless, I have to admire the breadth of geographiclib.) As for the question of SW platform, for now I'm working in MATLAB and will probably duplicate it in Python when I get to that stage. Currently, my shop is in the shift from MATLAB ($) to Python (free and more widely used); the world has changed a lot since we were a Fortran shop decades ago. So, I'm open to suggestions. At the moment I'm doing lots of reading on gravity models. | |
| Sep 27, 2018 at 16:24 | comment | added | Cristiano | I truncated the SGG-UGM-1 model: xb.sinomaps.com/EN/10.11947/j.AGCS.2018.20170269 to degree and order 15 to be used with sourceforge.net/projects/geographiclib. I can send it over. | |
| Sep 27, 2018 at 15:56 | comment | added | uhoh | Do you have the ability to just truncate EGM2008 to a lower number of coefficients, i.e. lower degree and order? If you are using a package, there might even be an option to do this automatically. | |
| Sep 27, 2018 at 15:48 | history | edited | uhoh |
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| Sep 27, 2018 at 15:48 | comment | added | uhoh | interesting question! The farther you get from Earth, the more accurate any truncated multipole model will be, so it's more a question of what level of accuracy you need at the lowest altitude you'll use, not the highest. So for example, it might be 1 part per million at 400 km above a reference sphere of 6378 km (just an example). If you'll only be working in the MEO neighborhood of GPS then all you'd need to say is roughly how accurate. Also you might state which software tools are you using so someone doesn't write a lengthy answer for package X and then find out you use Y. | |
| Sep 27, 2018 at 15:40 | review | First posts | |||
| Sep 27, 2018 at 16:20 | |||||
| Sep 27, 2018 at 15:35 | history | asked | Christopher Ison | CC BY-SA 4.0 |