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spedas / bleeding_edge

IDL-based Space Physics Environment Data Analysis Software (bleeding edge)
http://www.spedas.org
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Implement improved THEMIS-E FGM spin axis calibration #146

Open jameswilburlewis opened 5 months ago

jameswilburlewis commented 5 months ago

The FGM team is working on a method to recalibrate the increased FGM spin axis offset on TH-E, which takes the orbital position into account to generate a time-dependent offset correction. This will need to be implemented in IDL SPEDAS.

jameswilburlewis commented 3 months ago

FGM team will add additional fields (slope and intercept) to cal file, time of calibration entry will be perigee time. zero slope/intercept means no additional correction. These corrections may be intermingled with other calibration changes.

For times beyond the end of the calibration file, we can apply the last determined slope/intercept. But we will need to find our own perigee times. So this implies that padding of 1 orbit period (for STATE support data) prior to the nominal time range of interest will be necessary, to ensure we have all the relevant perigee times.

We will need a way for the FGM team to disable this correction for their cal parameter determination process.

Adrian P. will send an example of the new cal file format that we can use to develop and test our updates to the L1->L2 code.