Best practice creating a calendar of planned acquisition data for a geolocation

Optical Toolbox
#1

I need to inform my users on which dates Sentinel-2 is due to acquire MSI over Sardinia. Just two relative orbits map onto Sardinia: R022 and R065.
Each satellite, S2A and S2B, visits each relative orbit according to its own 10 day repeat cycle. Given initial dates of acquisition it is thus possible to add these repeat events to Google Calendar. See here:

My task is now to eliminate those dates from the calendar when the transit is planned NOT to acquire product - e.g. due to the sensors being in Vicarious mode, or similar.

Thus I analyse to the Sentinel-2 Acquisition Plans posted here:

in the form of KML files.

My current plan is to eliminate any date from my calendar that does not correspond to the xPath:

/kml/Document/Folder/Folder/Folder[name='NOMINAL']

Yet an alternative might be to eliminate those with xPath:

/kml/Document/Folder/Folder[name='VIC']

or
/kml/Document/Folder/Folder[name=‘DARK-O’]

Or, again, eliminate only those that do not correspond to xPath:

/kml/Document/Folder/Folder[name='NOBS']

what might be best practice?

#2

A more precise question:

This is the Information provided by the KML files
here: https://sentinel.esa.int/web/sentinel/missions/sentinel-2/acquisition-plans

The KML files display the footprint of the planned data takes on a map using the following convention:

• Planned data takes in Nominal mode
• Planned data takes in Vicarious mode
• Planned data takes in Calibration mode.

Only Nominal mode data takes are distributed to users.

But when I find a kml file that contains an acquisition tagged as in Vicarious mode it is also tagged as Nominal (e.g. https://sentinel.esa.int/documents/247904/3194886/Sentinel-2B_MP_ACQ_KML_20180323T110000_20180409T140000.kml ).

Q: So does that acquisition get distributed to users, or not?

#3

I have also no answer, but maybe @Jan has.
Jan can you help?

#4

Hello @gbrelstaff

Only NOBS (Nominal OBServation) Mode products are made available to Users. VIC_ Mode products are ‘hidden’ in the data catalogue as they are used by the supporting Expertise to montitor the performance of the instrument on a regular basis.

I can finds no instances of VIC acquisitions also being tagged as NOBS in the KML. I do find VIC acquisitions that are acquired in NOMINAL Timeliness - i.e. being made available between 3 and 24 hours after sensing (see Definitions - S2 User Guide).

Cheers

Jan

S2 MPC Operations Manager

#5

Thanks Jan

Nominal OBServation Mode clarifies things - thanks!

I’ll eliminate from my calendar any dates associated with an xPath:

/kml/Document/Folder/Folder[name='VIC' or name=‘DARK-O’]

retaining only those which have :
/kml/Document/Folder/Folder[name='NOBS']

and ignore the reference to NOMINAL in xPaths such as
/kml/Document/Folder[name=‘S2A’]/Folder[name=‘VIC’]/Folder[name=‘NOMINAL’]

1 Like
#6

Hi @Jan

I get 37 items - most of which provided News of downtime for Sentinel-2 Acquisition due to routine decontamination and associated calibration - if I google with the following search terms:
"decontamination" "sentinel-2" site:earth.esa.int/web/sentinel/news

Q:
Are these downtimes available in any more convenient form – other than say implying them from the absence of Folders in the aforementioned kml Acquisition Plans found here:
https://sentinel.esa.int/web/sentinel/missions/sentinel-2/acquisition-plans
I am still trying to build a calendar to advise those in the field of acquisitions (over Sardinia).