1. SCOS-2000 Training U2c - 1 31 i2r1 18/06/04 © Copyright 2004 European Space Agency Unit 2c – Telecommanding Functions Command Verification CEV - command verification (performed on server - Verifier) –Uplink Verification (based on reports from Ground Station) –Execution Verification (multiple stages) to verify command was received on board and executed correctly –Two Types: Report packets from S/C (PUS service 1) Database defined check, telemetry parameters with expected values –Validity of telemetry parameters used for verification is accounted for. –Also drives status consistency checking Verification dynamics: Release time (execution time of TT) IDLE PASSED/ PENDING PENDING/ PASSED/ FAILED/ SUPERSEDED UNKNOWN UNKNOWN/ FAILED/ PASSED/ UNVERIFIED/ AFFECTED/ UNCERTAIN PASSED/ UNCERTAIN FAILED UNVERIFIED Execution Duration (DB: CVS_START field) Verification Delay (Window of Uncertainty TC Spacon variable) Sampling Interval (DB: CVS_INTERVAL field) Manual consolidation if UNKNOWN Or AFFECTED Verification window

2. SCOS-2000 Training U2c - 2 31 i2r1 18/06/04 © Copyright 2004 European Space Agency Unit 2c – Telecommanding Functions There are 3 Uplink Verification stages: –Ground Station Reception (1 st stage) –Ground Station Uplink (Radiation/Transfer) (2 nd stage) –On-Board Reception (CLCW based) (3 rd stage) There are 4 Execution Verification stages: –Application Acceptance –Start of Execution –Execution Progress (multiple steps – SCOS-2000 supports 0 – 9) –Completion of Execution The possible states a stage can take: –Idle: Window not yet open –Pending: Window not open –Passed: TM successfully shows stage as successful –Failed: TM shows stage has failed (only for report based) –Unknown: No TM arrived to verify the stage after window closes –Superseded: A new command’s window uses same TM parameters and overlaps –Affected: A new command’s window uses same TM parameters but windows do not overlap –Unverified:Consolidated by user if previously Unknown or Affected, or if 3 rd stage AD number has been reset/ or re-used –Timed-out:UV stage not received G/S response (only applies to UV) –Uncertain Passed:TM arrived shows stage passed but after window has closed –Uncertain Failed:TM arrived shows stage failed but after window has closed –Assumed: Only applicable to 3 rd stage if not yet passed but subsequent stages have passed. –Disabled: Time-tagged command disabled at Execution (To be taken back from Rosetta) –Deleted: Time-tagged commands removed from on-board before execution

3. SCOS-2000 Training U2c - 3 31 i2r1 18/06/04 © Copyright 2004 European Space Agency Unit 2c – Telecommanding Functions Verification states explained IDLE PENDING PASSED FAILED DISABLED DELETED SUPERSEDED UNKNOWN AFFECTED TIMED OUT UNCERTAIN PASSED UNCERTAIN FAILED ASSUMED UNVERIFIED Execution duration (CVS_START) Uncertainty window (TC SPACON) Sampling period (CVS_INTERVAL) Late ….. Release of TT TC End of execution duration Timely TM “true” Timely TM “false” Overlapping TC for same TM TC for same TM Disabled at execution Removed by TC No TM at close of sampling window Consolidated by user 3rd stage UV only Late TM “true” Late TM “false” Passed later verification stage