1. OCS Scheduler Status Francisco Delgado T&S Software Manager
LSST Joint Technical Meeting
| Glendale, CA

2. Automatic & Dynamic LSST Scheduler
LSST as a robotic observatory
Targets are Field/Filter
Survey is automatic
Multiple science goals
Combine area distribution with temporal sampling
Dynamic adaptation to weather
Flexibility for survey adjustments during operations
Flexibility for changes in science programs

3. Prototype History OpSim1 Proof of concept in IDL
Simulation of visits with multiple science cases.
OpSim2
Python
Detailed model for the observatory and the weather
Embedded Scheduler prototype
Telescope design validation, site selection
OpSim3
Additional science cases and scheduling algorithms
Modular Scheduler prototype
Parameters exploration, survey definition validation

4. OCS Requirements Flow Down
Science Requirements Document
LPM-17
Science Book
Science Collaborations
LSST System Requirements
LSE-29
Metrics Requirements
DOC-15319
Observatory System Specifications
LSE-30
OpSim Requirements
LSE-189
Telescope & Site Requirements
LSE-60
Observatory Control System Requirements
LSE-62
Scheduler Requirements
LTS-347

5. History of Reviews 2011-08-29 NSF Preliminary Design Review
NSF Joint Interface & Management Review
OCS/TCS Software Review
NSF Final Design Review
OpSim/Scheduler Review
Start of Construction
OCS Interface Review
NSF Status Review
NSF/DOE Status Review
OCS/TCS Software Status Review
T&S Integration Review
DOE/NSF Commissioning Review

6. Observatory Control System
Control Context
Observatory Control System
TCS
OCS Application
OCS Scheduler
CCS
OCS Sequencer
OCS EFD
DMCS

7. Operations Simulator v4
Simulation Context
Operations Simulator v4
OCS Scheduler
Simulated OCS (SOCS)

8. OCS communications Middleware
Control Data Flow
OCS Operator
OCS Remote
OCS Monitor
OCS Application
Control
Scheduler
History
OCS
EFD
OCS Sequencer
Telemetry
Image Quality
Cmd
Visits
Targets
Sched
Telem
Visits
OCS communications Middleware
TCS
CCS DM

9. OCS communications Middleware
Simulation Data Flow
Control
Scheduler
History
Telemetry
Image Quality
Targets
Sched
Telem
Visits
OCS communications Middleware
SOCS

10. Internal Block Diagram
Time
Main
Driver
Sched Config
Scheduler
Sched Mode
Control
Targets
Targets
Downtime
Cost functions
Sched Telem
Degraded
Sched Telem
Slew Time
Observatory Model
Telemetry
Observatory conditions
Sky
Model
Pre-Calc Data
Candidates
Weather forecast
Proposals
Image Quality
Environment conditions
Value functions
History
Quality parameters
Observation History
Past observations
Visits
Current observation 10

11. Science Proposal Classes
Scripted proposals
Designed to produce a pre-determined sequence
Basic parameter: scripted cadence of targets
Area distribution proposals
Designed to obtain uniform distribution
Basic parameter: goal visits per filter
Look-ahead info: future available time for the targets
Time distribution proposals
Designed to obtain specified intervals in sequences
Basic parameter: time window for visits interval
Look-ahead info: visibility for next intervals

12. Accuracy changes Repeatability
100% repeatability in observations sequence and slew states
Alt-Az precision
Alt-Az estimated at slewInit and recalculated at slewFinal
Difference can be seen between “target” and “slewFinalState”
Remaining tracking time
Taken into account before sending target (+30 seconds)
Avoid reaching tracking limits in altitude, azimuth or rotator

13. Accuracy changes Sky brightness model
New model, per band, includes explicit twilight
Configurable moon avoidance
New sky model also includes it (built-in)
No caching ranks (reuse)
Everything is ranked at each visit

14. Ranking a Target Hard constraints Global
Filter change rate, burst and average
Observatory kinematic limits
Per Proposal
Airmass
Transparency
Seeing
Sky region (dynamic for rolling cadence)
Per Filter
sky brightness

15. Area distribution algorithms
Need ratio

16. Area Distribution changes
Time window hybrid
Optional configurable grouped timed visits
The first in the group is area ranked
The followings in the group are time-window ranked
Same night revisits constraint
Revisits to the group during the same night can be avoided
No overflow

17. Rank Bonuses
Airmass bonus
Hour Angle bonus

18. Ranking a Target Need Function Time Distribution
Look-ahead: future sequence feasibility
Value Function

19. Proposals priorities changes
Self balancing mechanism

20. Slew time cost

21. Filter change cost

22. Final target rank
Value Boost and Cost

23. Serendipity changes Proposal Id based
PropId is included in the observation
Winners and Losers counted
If serendipity is allowed, both lists are searched
Coadding is now optional
Coadding values for a target in more than one proposal can be disabled

24. OCS Scheduler plan Scheduler v0.1 2015-July OCS Middleware framework
Scheduler v December
Observatory kinematic model
Scripted targets proposal
Scheduler v May
Area distribution proposals
Sky brightness model
Airmass bonus
Slew time cost function
Dynamic configuration

25. OCS Scheduler plan Scheduler v1.0 2017-March
Filter swaps around new moon
Filter change rate constraints
Filter change cost function
Downtime handling
Clouds handling
Seeing handling
Hour angle bonus
Self balancing proposals
Grouped visits for Area distribution proposals
Time distribution proposals with sequences
Parallel subsequences
Rolling cadence
Deep drilling

26. OCS Scheduler plan Scheduler v1.1 2017-August
Deterministic look-ahead area distribution
Scheduler v December
Deterministic look-ahead time distribution
Scheduler v April
Speed performance improvements
Scheduler v October
Warm start to resume partial survey

27. OCS Scheduler plan Scheduler v1.5 2019-March Dithering patterns
Scheduler v August
Predicted schedule publication
Scheduler v December
Weather forecast handling
Scheduler v May
Community provided optimizations

28. (Metrics Analysis Framework)
Validation
OpSim
(Operations Simulator)
Observations Database
Scheduler
SOCS
(Simulated OCS)
MAF
(Metrics Analysis Framework)

29. Analysis of runs

30. Quality Assurance Unit Test Integration Test with SOCS
Algorithms Validation
Validation runs by Systems Engineering Simulations
Release Tests (includes installation and fiducial run)
Scientific Validation by Science Collaborations
Integration Tests with OCS

31. Software Engineering Tools
Model Based Systems Engineering
SysML modeling with Enterprise Architect
PMCS with Primavera
Coordination and progress with JIRA
Documentation in Docushare
Interface controlled in OCS SAL with XML
Version control with Git, Stash
Mirrored on GitHub
Continuous Integration with Jenkins
Coding standards from Telescope group and Simulations group

32. Summary Scheduling algorithms validated during prototype effort
Scheduler designed for control and simulation context
Development plan coordinated with SOCS for I&T
Integration activities with Observatory Control System
In Control context the Scheduler drives the LSST survey
In Simulation context the Scheduler evaluates alternate surveys for parameters exploration and optimizations during operations