SolarOrbiter PAS

Description

Previously, up to 2021/06/10, we were using PAS full-sampling (FS) at the begining and end of each snapshot period, with :

START_ENERGY = 4, NB _ENERGY = 90
START_ELEV = 0, NB_ELEV = 9

A typical PAS FS is : 90 x 9 x 11 x int16 = 17820 bytes

Starting on 2021/06/10 we tried another PAS configuration with:

START_ENERGY = 14, NB _ENERGY = 80
START_ELEV = 1, NB_ELEV = 7

That conduces to have smaller PAS data packets for FS : 80 x 7 x 11 x int16 = 12320 bytes

Problem encountered

From 2021/06/10 to 2021/01/13 we found some new errors in PAS data processing : some PAS FS were missing

The 2 columns indicates the number of leading (sample 1/9) or trailing (9/9) FS and their ratio (received/expected)

2021-06-10 ( 183  162) FS /  269 = ( 68.03%  60.22%) OK
2021-06-11 ( 165  158) FS /  280 = ( 58.93%  56.43%) OK
2021-06-12 ( 146  135) FS /  282 = ( 51.77%  47.87%) OK
2021-06-13 (   5    3) FS /   20 = ( 25.00%  15.00%) OK

See documents/SNAPSHOT/snapshot.txt

2021/06/10 Example of problem

Here is an extract of PAS FS header and data packet

1 | CCSDS.Read_CCSDS_packet        | PACKET 1616
1 | STATS.Register_SID             | SID = 203 count =     26
1 | TM.Get_TM_handler              | APID ( 96,12) TM ( 21,  3) SEQ (00386,3) Size =    20  2021-06-10T00:51:25.029 : SID (  203,   26) : SWA_TM_SCI_PAS_TRIGG_SNAP_COMPR_FIRST
1 | SCI.Parse_PAS_3D_C_snapshot    | Sample 9/9
1 | SCI.Parse_PAS_3D_C_snapshot    | SCET = 2021-06-10T00:51:14.153270144
1 | SCI.Parse_descriptor           | K = 1 ENERGY = (14,80) ELEVATION = (1,7) CEM = (0,11)
1 | SCI.Parse_descriptor           | Info = 2 K = 1 Sampling size = 12320 Total size = 12320 bytes
1 | SCI.Parse_PAS_3D_C_snapshot    | LCI =  24
1 | CCSDS.Read_CCSDS_packet        | --------------------------------------------------------------------------------
1 | CCSDS.Read_CCSDS_packet        | PACKET 1617
1 | STATS.Register_SID             | SID = 204 count =     26
1 | TM.Get_TM_handler              | APID ( 96,12) TM ( 21,  6) SEQ (00387,3) Size =   462  2021-06-10T00:51:25.029 : SID (  204,   26) : SWA_TM_SCI_PAS_TRIGG_SNAP_COMPR_DATA
1 | SCI.Parse_PAS_3D_C_snapshot    | CDS = 40 Size = 454 bytes
1 | SCI.Uncompress_data            | Compressed/expected/uncompressed sizes =    454  12320  12288 compression factor = 27.14
W | SCI.Uncompress_data            | usize = 12288 < expected 12320 (missing 32 bytes)
1 | SCI.Parse_PAS_3D_C_snapshot    | Total size = 12288/12320
E | SCI.Parse_PAS_3D_C_snapshot    | Uncomplete data : 12288/12320 bytes
1 | SCI.Write_CDF_record           | Record 00089 : Info = 2 K = 1/1 Sample = 9/9

After uncompressing the data packet, we were expecting to receive 12320 bytes, but we received only 12288 bytes (32 bytes missing)

In a first processing, we were rejecting these packets, that leads to "Missing PAS snapshots" in our plots.
In a second precessing, we completed these uncomplete packets with fill_values, to get the more complete plot possible.

NB : the problem doesn’t occur for all PAS FS, but sometimes for more than 50% of FS

Same problem on 2021/06/21 to 2021/06/23

We could find same kind of uncomplete uncompressed data for both snapshot or burst mode FS, with the same characteristics.

Example in Burst mode

1 | CCSDS.Read_CCSDS_packet        | PACKET 125711
1 | STATS.Register_SID             | SID = 209 count =    356
1 | TM.Get_TM_handler              | APID ( 97,12) TM ( 21,  3) SEQ (04925,3) Size =    20  2021-06-21T22:07:06.754 : SID (  209,  356) : SWA_TM_SCI_PAS_TRIGG_OBURST_COMPR_FIRST
1 | SCI.Parse_PAS_3D_C_burst       | Sample 61/296
1 | SCI.Parse_PAS_3D_C_burst       | SCET = 2021-06-21T22:02:09.866040064
1 | SCI.Parse_descriptor           | K = 1 ENERGY = (14,80) ELEVATION = (1,7) CEM = (0,11)
1 | SCI.Parse_descriptor           | Info = 3 K = 1 Sampling size = 12320 Total size = 12320 bytes
1 | SCI.Parse_PAS_3D_C_burst       | LCI =  24
1 | CCSDS.Read_CCSDS_packet        | --------------------------------------------------------------------------------
1 | CCSDS.Read_CCSDS_packet        | PACKET 125712
1 | STATS.Register_SID             | SID = 210 count =    356
1 | TM.Get_TM_handler              | APID ( 97,12) TM ( 21,  6) SEQ (04926,3) Size =   314  2021-06-21T22:07:06.755 : SID (  210,  356) : SWA_TM_SCI_PAS_TRIGG_OBURST_COMPR_DATA
1 | SCI.Parse_PAS_3D_C_burst       | CDS = 30 Size = 306 bytes
1 | SCI.Uncompress_data            | Compressed/expected/uncompressed sizes =    306  12320  12288 compression factor = 40.26
W | SCI.Uncompress_data            | usize = 12288 < expected 12320 (missing 32 bytes)
1 | SCI.Parse_PAS_3D_C_burst       | Total size = 12288/12320
E | SCI.Parse_PAS_3D_C_burst       | Uncomplete data : 12288/12320 bytes
1 | SCI.Write_CDF_record           | Record 01370 : Info = 3 K = 1/1 Sample = 61/296

Same PAS configuration :

80 energy x 7 elevation x 11 CEM x int16 = 12320 bytes expected,
but only 12288 bytes uncompressed for sample 61/296

Solar Orbiter PAS

PAS Snapshot Full-Sampling problem

Description

Problem encountered

2021/06/10 Example of problem

Same problem on 2021/06/21 to 2021/06/23