Level 1.5 Processing IssuesMartin BatesRAL

Level 1.5 Processing IssuesGeolocationCurrent StatusTSOL Jitter (CSOL-TSOL) correctionLongterm TSOL Jitter SolutionComparisons with RGP ProcessingUpcoming Updates to ProcessingProcessing Validation

Current StatusLevel 1.5: Adhoc E-W geolocation correctionsinusoid (amplitude, phase, offset tunable)ESU dependentaccurate to ~1 pixel, a bit worse N-S. Level 2: fit to SEVIRI data (formerly MS7A)decoupled from Level 1.5accurate to ~ 0.2 pixels (< 0.5 pixels)09 Nov 2003

TSOL JitterPredicted TSOL actual TSOLas used by IMPFpredicted TSOL (CSOL) from rotational modelTemporary schemedata available on ftp server at EUMETSAT since 16 Februarycoverage > 99.6 % (dropouts at sun-satellite colinearity)copy across and use as correction to E-W geolocationggsps correction for early April.

TSOL Jitter14 Nov 2003data spikey needs filtering

Smoothed TSOL JitterResult of median filter ( 1 minute)One spike in close-up

Corrected Data (15 Nov 2003)no filtering

am/pm Systematic15 Nov 2003

am/pm Systematic16 Nov 2003

TSOL Jitter Correction23 March 2004

TSOL Jitter Correction23 March 200423 March 2004am/pm systematic still presentoffset slightly different

Long term solutionRobustness of ftp server solution in question.Longer term solution:append (TSOL Jitter) value to GERB packetcorrection algorithmically no differentimproved reliability and timeliness of informationTimescale: 6-12 months.requires Engineering Change Proposal (for IMPF and UMARF)still to be approved by EUMETSATSEVIRI reprocessing ?can then get values for before 16 Feb.

RGP ComparisonsProcess data from 14-16 Nov 2003 using TSOL jitter correction.Compare to RGP geolocation (high CPU fit) comparing to SEVIRI.

North-South Compression15 Nov 2004 11:56:58 (SW)Still there !N/S offset not perfect for these data

Quasi-Rotation15 Nov 2004 11:56:58 (SW)Also still there ...

Azimuth vs Column15 Nov 2004 11:56:58 (SW)Looks better ...

TOTAL at night15 Nov 2004 00:12:47 (TOTAL)Azimuth vs pixelElevation vs pixelSimilar results

SW in eveningAzimuth vs ColumnDark !15 Nov 2004 17:58:57 (SW)

Retune Optical Model ?1. Could be due to local deformations in one of the mirrors but no estimate of possible sizes of effects2. Image ratio plots more structure in GGSPS plotGGSPSRGP

Geolocation PlansInterim TSOL Jitter Correction (April)Long term TSOL Jitter Correctionfor improved robustnessstill to be approved, end of year ?Optical Model tune using RMIB infoAxis misalignmentsMSG spin to MSG structurelarge (~0.3 ?)changes at each manoeuvre action on EUMETSAT to investigateMirror Side Effects (non-parallel N/S ?)

Upcoming Processing UpdatesNew BAT, BBRAD tablesbut may be coordinated with data releaseOffline gains (stray light & moon avoidance)depends on gain stability:if update < once per monthuse offline gains (data table)if update more frequentlyavoid problem regions oruse gains calculated at good times of daystartup problems & time dependent processingStray Light Correction TBDNumerous minor updatesNCR fixesadditions (diagnostics) to NANRG productconfidence flag definitions

Processing ValidationGeolocation ValidationComparisons with SEVIRI / RGP geolocation (RMIB)Overall Validationseries of unit and integration tests done (test data, limited set of circumstances)step by step validation using real data and checkpoint files suggested (validation plan) TBDmonitoring of calibration parameters using engineering report (Imperial).