Extending Flux Modelling in GMAT Drag Models

Development related to the GMAT core and GUI

Extending Flux Modelling in GMAT Drag Models

Postby shughes » Mon Jul 16, 2012 12:12 pm

Vision and Scope

Density models in GMAT require as input space weather data such as F10.7 solar flux values and Geomagnetic indices. These quantities are time varying and include both measured and predicted values that are provided by several sources. GMAT currently only supports constant values for space weather data which, while useful for early analysis, is highly inaccurate. This project will provide new functionality that will allow the user to provide historical data, near term (daily) predicted data, and long term (monthly) predicted data for space weather phenomenon. The data sources we will use are provided by the Center for Space Standards and Innovation (CSSI) and by Ken Schatten. We will continue to support the constant values.

Specification/Requirements

The peer-reviewed interface specification for this functionality is located here:
https://docs.google.com/document/d/11JP ... thciu5h7tk

All of the info below is in the spec, but here is a summary. Treat the spec as the living doc!! This info may change once we start writing code.
The preliminary script interface:
Code: Select all
Create ForceModel MyForce
MyForce.Drag.AtmosphereModel = None;
MyForce.Drag.HistoricAndNearTermWeatherSource = CSSISpaceWeatherFile;
MyForce.Drag.LongTermPredictedWeatherSource = SchattenFile;
MyForce.Drag.F107 = 150;
MyForce.Drag.F107A = 150;
MyForce.Drag.MagneticIndex = 3;
MyForce.Drag.CSSISpaceWeatherFile = ‘../MyFiles/SpaceWeather.txt’;
MyForce.Drag.SchattenFile = ‘../MyFiles/SchattenPredict.txt’;
MyForce.Drag.SchattenErrorModel = PlusTwoSigma;
MyForce.Drag.SchattenTimingModel = ‘NominalCycle’


The preliminary GUI interface is documented in the spec here:

https://docs.google.com/document/d/11JPQRqThtRx68hbAhFljE5StvQJsRCxaZoxfV0eKVnU/edit?hl=en_US#heading=h.y6yclxxudtwj

Plan/Milestones

The plan assumes that there are three main components to the flux reader: (1) the Schatten file reader, (2) the CSSI file reader, and (3) an executive that serves as the main interface to GMAT and determines which file to call and what data to return. Should this change, the plan will need to be modified.

    KARI Milestones
  • Read/Modify/Finalize interface design
  • Design/Review/Finalize Flux Reader Class
  • Write/Unit Test Schatten File Reader
  • Write/Unit Test CSSI File Reader
  • Integrate File Readers into Flux FIle infrasctructure
  • Integration test the Flux Reader class
    GSFC Milestones
  • Integrate Flux File Reader into GMAT (hook up scripting and GUI)
  • System test the flux file capability in GMAT
shughes
 
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Re: Extending Flux Modelling in GMAT Drag Models

Postby shughes » Mon Aug 20, 2012 1:04 pm

After thinking more about the requirements, I think we need an additional requirement to allow the user to use either the raw data or interpolated data.

The requirements might read something like this:

The system shall support the following options for Near Term space weather data:
+ Use raw data from the file
+ Use cubic spline interpolation
The system shall support the following options for long-term space weather data:
+ Use raw data from the file
+ Use cubic spline interpolation
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Re: Extending Flux Modelling in GMAT Drag Models

Postby shughes » Mon Aug 20, 2012 1:43 pm

This is what the MSISE density models need as input from the Flux files: This is from help in matlab's atmosnrlmsise00 function

F107A :the day average of F10.7 flux (centered on doy).
If F107A is input, F107 and APH must also be input. The effects
of F107A are neither large nor well established below 80,000
meters, therefore the default value is set to 150. See
Limitation section for more information.

F107 :the daily F10.7 flux for previous day. If F107 is
input, F107A and APH must also be input. The effects of F107 are
neither large nor well established below 80,000 meters,
therefore the default value is set to 150. See Limitation
section for more information.

APH : magnetic index information. If APH is
input, F107A and F107 must also be input. This information
consists of daily magnetic index (AP), 3 hour AP for current
time, 3 hour AP for 3 hours before current time, 3 hour AP for 6
hours before current time, 3 hour AP for 9 hours before current
time, average of eight 3 hour AP indices from 12 to 33 hours
prior to current time, and average of eight 3 hour AP indices
from 36 to 57 hours prior to current time. The effects of daily
magnetic index are neither large nor well established below
80,000 meters, therefore the default value is set to 4. See
Limitation section for more information.
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Preliminary Design for Flux Reader Classes

Postby shughes » Wed Aug 22, 2012 1:16 pm

shughes
 
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Re: Extending Flux Modelling in GMAT Drag Models

Postby dev-wcs » Wed Oct 17, 2012 1:14 pm

Your design spec indicates that Ap and Kp are different, Ap being used for MSISE and Kp used by JR. But Ap is a vector of values and Kp is a single value, correct?

The Schatten file example you show has a column marked ap - I assume that is the Ap - but only one value?. Is there no Kp on the file (for JR)? If not, then do we always need the user to supply a constant Kp, even if the other data is read from the file?

I see that this is addressed somewhat in the comments on the Spec.
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Re: Extending Flux Modelling in GMAT Drag Models

Postby darla » Mon Sep 22, 2014 11:56 am

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Re: Extending Flux Modelling in GMAT Drag Models

Postby henrybill11 » Thu Oct 26, 2017 6:36 am

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