20 October 200820 October 2008 LBT Q3 2008 Eng/SW ReviewLBT Q3 2008 Eng/SW Review 11

LBT Q3 2008 Eng/SW LBT Q3 2008 Eng/SW ReviewReview

PCS – Pointing Control SubsystemPCS – Pointing Control Subsystem

Michele De La PeMichele De La Peñaña

20 October 200820 October 2008 LBT Q3 2008 Eng/SW ReviewLBT Q3 2008 Eng/SW Review 22

HighlightsHighlights PCS Interfaces (GCS, MCSPU) PCS Interfaces (GCS, MCSPU)

GCS: Pointing Correction GCS: Pointing Correction Improved algorithm which applies the difference between the PCS “predicted” versus the Improved algorithm which applies the difference between the PCS “predicted” versus the

GCS “measured” guide star locationGCS “measured” guide star location Better handshaking implemented to indicate when it is OK for GCS to verify the guide star Better handshaking implemented to indicate when it is OK for GCS to verify the guide star

is positioned on the hotspot before closing the guide loopis positioned on the hotspot before closing the guide loop MCSPU: PCS Cold Start and New Target TrajectoriesMCSPU: PCS Cold Start and New Target Trajectories

Better handshaking implemented which alleviates having to issue duplicate Presets - Better handshaking implemented which alleviates having to issue duplicate Presets - “Late” PCS trajectory communication “Late” PCS trajectory communication mount/rotator enters HOLD mode mount/rotator enters HOLD mode reduces reduces observing efficiencyobserving efficiency

The philosophy is the mount should react to the ever-changing pointing demand - The philosophy is the mount should react to the ever-changing pointing demand - PCS is a pure compute engine while MCSPU has the responsibility to recognize PCS is a pure compute engine while MCSPU has the responsibility to recognize discontinuities due to new target requestsdiscontinuities due to new target requests

Functionality to Support InstrumentsFunctionality to Support Instruments New functionality allows the observer to reposition where a target is New functionality allows the observer to reposition where a target is

imaged in the instrument focal plane (“hotspot” update) – imaged in the instrument focal plane (“hotspot” update) – pointing pointing origin updateorigin update vs vs ditherdither. .

Observers can update the effective target wavelength (due to changing Observers can update the effective target wavelength (due to changing filters) and not have to issue a new Preset filters) and not have to issue a new Preset improved efficiency improved efficiency

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Open IssuesOpen Issues TechnicalTechnical

Investigation of guiding issues (jumps/jiggles/jitters)Investigation of guiding issues (jumps/jiggles/jitters) Resolve the LBC “guide correction growth” problem Resolve the LBC “guide correction growth” problem random occurrence random occurrence Tuning of gains and filters used to modulate the Az/El guiding corrections to avoid over-Tuning of gains and filters used to modulate the Az/El guiding corrections to avoid over-

correction and system oscillationcorrection and system oscillation Discussion on-going and an actual plan being formulated for near-term data collectionDiscussion on-going and an actual plan being formulated for near-term data collection

Thorough examination of kernel guide correction filter and applicationThorough examination of kernel guide correction filter and application Resolve high elevation guide oscillations (somewhat addressed in new kernel)Resolve high elevation guide oscillations (somewhat addressed in new kernel)

Achieve definitive understanding of the various kernel angles, transformations, Achieve definitive understanding of the various kernel angles, transformations, and trajectory offsets to apply a comprehensive solution for each instrumentand trajectory offsets to apply a comprehensive solution for each instrument

Evaluate and utilize the updated (and slightly incompatible) pointing kernelEvaluate and utilize the updated (and slightly incompatible) pointing kernel ScheduleSchedule

Concern not enough on-sky testing time for technical observingConcern not enough on-sky testing time for technical observing Primarily weather, but also sky time scarce resource for testing (unit and integration)Primarily weather, but also sky time scarce resource for testing (unit and integration)

Reconcile expectations when programmer participating in on-sky instrument Reconcile expectations when programmer participating in on-sky instrument support and required to implement new and robust functionalitysupport and required to implement new and robust functionality

FinancialFinancial Continued support for RAL consultingContinued support for RAL consulting

ResourceResource NoneNone

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Planning (Q4/2008)Planning (Q4/2008) Resolution of the “Open Issues” (Oct…)Resolution of the “Open Issues” (Oct…) Initiation of a new PCS GUI (Dec)Initiation of a new PCS GUI (Dec)

Incorporates the functionality from current PCS and Preset GUIsIncorporates the functionality from current PCS and Preset GUIs Provides additional control and monitoringProvides additional control and monitoring Sets the migration path for binocular supportSets the migration path for binocular support

Implement telemetry moduleImplement telemetry module True Binocular Support (Dec…)True Binocular Support (Dec…)

Implementation of Implementation of basic structural basic structural modifications to PCS to modifications to PCS to accommodate the binocular arbitrator (Dec…)accommodate the binocular arbitrator (Dec…)

Define/design interface between the PCS and PSF for the tip/tilt Define/design interface between the PCS and PSF for the tip/tilt computation (Q1/2009)computation (Q1/2009)

Elaborate/design the model for co-aligned and misaligned Elaborate/design the model for co-aligned and misaligned observations (Q1/2009)observations (Q1/2009)

Implementation commencement – LBC emphasis (Q1/2009)Implementation commencement – LBC emphasis (Q1/2009)