Telemetry data

Owned by Marco Peters
Last updated: 2020-11-18 by Sabine Embacher
2 min read

In order to perform the geometric correction, the chris-box needs telemetry files. They are publicly available on an ESA/REDU archive server: http://194.78.233.110/products/data/CHRIS_Additional_data/

The server uses an old security protocol. That’s why users will see warnings when accessing the server. But after accepting the risks the data is accessible. At the time of writing the easiest access is possible with the Firefox browser. An update is already planned.

The archive provides individual files for the most recent acquisitions, older files are bundled in compressed files.

 

A pre-packaged archive is available for download from Archive_CHRIS_Telemetry_Data_20201028.zip. It has been packed on the 28th of October 2020

To find the corresponding telemetry files for a given acquisition follow these steps:

  1. Get [Target Name] and [Date] from image meta data; the dashes '-' in the date must be removed (e.g. for image CHRIS_MB_080501_9BE1_41 meta data [Target Name]=Manly-Beach and [Date]=20080501 removing the '-' from the meta data date value '2008-05-01')

  2. Connect to the telemetry archive

  3. Use a filter *.[Target Name]_?????_CHRIS_center_times_[Date]_* to locate the Image Center Times file (e.g. it would find: Pass9301.Manly-Beach_39905_CHRIS_center_times_20080501_65534)

  4. ????? should match a five-digit string to be used as reference [Ref] (e.g. in this case it would be [Ref]=39905)

  5. Use a filter CHRIS_[Ref]_*.tar.gz to locate the compressed GPS file (e.g. it would find: CHRIS_39905_39909.tar.gz)

  6. Extract from the gzip archive the file: CHRIS_[Ref]_*_PROBA1_GPS_Data, where PROBA's GPS position and velocity data are recorded. There also is a second file PPU_UPLOAD_*, which can be ignored (e.g. extract CHRIS_39905_39909_PROBA1_GPS_Data)