Requirements for real-time observing ------------------------------------ General Description: -------------------- How ALMA executes observations to complete observing projects. - Execution of an OB is done by execution of a script. - The Scheduler maintains at all times a list of prioritized OBs. - Whenever on OB is finished, the top priority OB is executed. - If this OB belongs to an active Observing Session: it is executed in that session. - If not, a new session is initiated: . The previous session is terminated after execution of the concluding OB if needed. . Resources (antennas, correlator) are requested to the control system and/or operator. . The data reduction pipeline(s) for that session is started. . The preamble OB is executed followed by normal OBs. - When each OB is finished it returns a status to be used by the scheduler, for further evaluations of OB priorities in the same programme. OB Execution: ------------- . An OB shall be able to be described and executed by a script, including setup cpmmands and observe commands. . The setup commands shall allow to prepare the next observation (Descriptor of next observation) while the current observation is executed. . The observing script shall be able to test the current OT and other objects such as weather/environment variables, pipeline calibration results from the current session and from sessions of the same programme/project executed previously or in parallel , ... . Observe commands shall copy the next OT onto the current OT and execute it. OB Script setup commands ------------------------ - Initialize the descriptor from calling script. The antenna list is initialized from the current subarray. - Put Value in observation descriptor: Give a value to a specified OT parameter, array, ... - Save/Restore Observation descriptor to/from file: - Preset command(s): - Execute quasi-real time calculations based on next (passive) OT. . Fill in Source parameters from Catalogs into next OT . Compute next source horizontal position for testing . Complete correlator setup parameters if needed . Current observation is *unaffected* - Error conditions: . Catalog Not found . Source not in catalog . Ephemeris file not found . Impossible Correlator configuration OB Script observe commands -------------------------- - When current Observation is finished: - Copies Next OT into Current OT - Executes Current OT, producing data. - Update OB status information, made available to the scheduler. (integration time, theoretical rms, ...) Observation Descriptor contents (draft) ---------------------------------- Project ID Sub-array ID Observation Block ID Number of Antennas=NA Antenna(NA) Antenna ID Position of Antenna (X,Y,Z) Antenna Station Pointing Model Axes Offset Encoder Zeroes Collimations Az Inclinations Focus Corrections (X0,Y0,Z0, X1,Y1,Z1, ...) Pointing Offsets of Optical Telescope ... Pattern System (Hor, Eq) Mode {"None", "Circle", "Points"} Start coords Center coords (C) Angular Velocity (C) Number of points (P) List of coords, times (P) ... Calibration Parameters Number of points=NPC Point(NPC) Frequency Forward Efficiency Aperture Efficiency Atmospheric Model Frequency Band(NFB) Pointing offset (Az,El) for H Pointing offset (Az,El) for V Focus offset (Z) for H Focus offset (Z) for V LO1 Phase offset Frequency Window (NFW) LO2 Phase Offset SideBand Gain Ratio Number of Frequency Bands = NFB Frequency Band(NFB) Frequency Band ID Mode {Active, Standby} LO1 Frequency Number of Spectral Windows = NFW Window(NFW) Setup Mode {EXPLICIT, AUTO} Polarization {H, V, HH&VV, ALL} Line ID Line Rest Frequency Velocity Interval (min,max) Velocity Resolution LO1 SideBand LO2 Frequency LO2 SideBand IF Frequency IF Frequency Bandwidth Frequency Resolution Number of Sources (=NS) Source(NS) Source ID Catalog {YES NO} Catalog name Source Status {Active, Standby} SolSys Object {YES, NO} SolSys Name or FileName Coordinate System {EQ GA HO ...} Epoch Lambda at Epoch Beta at Epoch Lambda Motion at Epoch Beta Motion at Epoch Velocity Velocity Frame {OBS, GEO, HEL, LSR} ... (EMBar, SSBar ?) Doppler Track {YES, NO} Flux Number of Frequencies Frequencies Fluxes Source Info {PHASE_CAL,FLUX_CAL,BAND_CAL,TEST_TARGET,SCIENCE_TARGET...} Phase Center Pattern System (Hor, Eq) Mode {"None", "Circle", "Points"} Start coords Center coords (C) Angular Velocity (C) Number of points (P) List of coords, times (P) ... Integration Time SwitchingMode Number of States State Duration Blanking (?) Nutator Offsets LO1 Frequency Offset LO2 Frequency Offsets (4) Weight (for Pipeline) ... Water Vapour Radiometer Use {YES NO} Data Processing Script Telescope Calibration Project Calibration Imaging Glossary: --------- - Dump: basic integration time of correlator - Switching State: a set of dumps, all identical in configuration (except for primary antenna motion) [NB: Possible synonym is Switching Phase; but this is very confusing when one speaks also of phase switching.] - Integration: basic written unit ; may consist of a set of switching states in case of frequency switching, nutator switching. - Observation: a set of integrations while the antennas complete an elemental pattern across the source, and possibly while frequency switching, nutator switching ... - Scan: a set of observations with a common goal: e.g. pointing scan, focus scan, atmospheric amplitude calibration scan, ... - Observation Block (OB): a set of scans constituting an uninterruptible scheduling unit. - Observing Session (OS): a set of observation blocks constituting an uninterrupted scheduling unit, in the same project. - Project data: The whole set of observing sessions in a given project. - Observing Programme: Is this a synonym of Observing Project ? - Observation Descriptor (OD): the hierarchical set of parameters that define the current observation. - Interactive Commands: interactive commands can be used to specify descriptor parameters for the next observation, start the next observation, cancel the current observation, ... - Observing Script: An observing script is used to define the sequence of observations, with loops, conditional tests using environmental parameters (weather, pipeline results, current scheduling status, ...) - Observing Tool: A GUI interface, which is used by the observer to prepare observations from templates. Observer input consists of fixed parameters, range of values for parameters, algorithms used for variable parameters, ...) ; the Observing Tool shall be to able to produce an observing script, or may operate ALMA directly.