The ALMA TelCal subsystem Dominique Broguière, Institut de RadioAstronomie Millimétrique (IRAM) TelCal Phasing meeting – Grenoble -10/12/2012

TELCAL Phasing meeting - 10 December Presentation layout TelCal overview ALMA software architecture TELCAL software architecture Offline mode of TelCal

3 TelCal overview (1/3) TELCAL is the on-line calibration software for the ALMA array. On-line calibration groups all the operations needed to maintain the ALMA interferometer optimally tuned to successfully execute the planned observations. On-line calibration primarily deals with : –pointing and focus offset computations –delay measurements –solving of antenna positions –measurement of atmospheric absorption and of phase radiometric correction –monitoring of phase and amplitude on an astronomical calibrator source –bandpass and sideband ratio measurements –holography to compute the panel adjustment needed to improve surface rms and monitor surface quality –pointingModel

4 TelCal overview (2/3) TELCAL software has been developed since People involved in TELCAL : –Robert Lucas : lead until –Dominique Broguiere (IRAM) lead since –Jean-Christophe Roche (IRAM) Alexis Tejeda was working in TELCAL until June 2012, currently working in JAO Juan Pardo was working on ATM library until end of 2011

5 TelCal overview (3/3) Programming languages : –70% C++ : calibration code and C++ Corba components –13% python : offline scripts –12% fortran90 : holography (gildas) – 5% java : Corba components SLOC (Source Lines Of Code) report for TELCAL –Calibration (Engines,TelCalSolvers, tpoint andTools modules) : lines –CORBA components (TelCalDataManager, TelCalPublisher, TelCalMaster, and DCsimulator modules) : lines –Offline scripts (AsdmReader, Tasks and Standalone modules) : lines –ATM library : lines –Holography (Gildas) : lines (~ lines of fortran90 developed for ALMA holography and ASDM-PDB filler, rest is frozen code) –Shared Simulator (SharedSimulator and SharedSimLib) : lines –Others (TelCalScripts module) : 1300 lines Total : ~ lines

ALMA Software

TelCal and the other subsystems TELCAL CONTROL CORRELATOR EXECUTIVE ARCHIVE Results (ASDM) Start/stop Metadata (ASDM ) Correlator data Totalpower data CONTROL (DataCapturer) Interfaces of TELCAL with other subsystems

TELCAL architecture : containers and components Based on ACS (Alma Common Software) infrastructure and tools CORBA : enables software components written in several languages (C++, java, python) and running on different machines to work together Components are deployed in containers. This simplifies the management of components Interface of components described in IDL language Events used for asynchronous exchanges AudioVideo streams for binary data transfer (high rates). New implementation ( ) based on RTI DDS.

TELCAL MASTERCOMPONENT TELCAL PUBLISHER ARCHIVE TELCAL TOTALPOWER RECEIVER (n components) TELCAL DATAMANAGER (n components) CORBA components of TELCAL TOTALPOWER DISTRIBUTOR DATACAPTURER CORRELATOR DISTRIBUTOR EXECUTIVE DATACAPTURER scripts TELCAL PARAMETER_TUNING TELCAL ARRAY CONTROL

TelCal modules Architecture : 4 main packages : TelCalMaster : starting and stopping the subsytem TelCalDataManager : receiving, filtering and organizing all data streams TelCalResults : processing the calibration TelCalPublisher : publishing the results

ATM package Result of research by J. Cernicharo and J. Pardo in Madrid Agreement to use and extend this for ALMA (TelCal and Offline subsystems). Predicts atmospheric emission, absorption and path- length for all ALMA bands Water vapor retrieval algorithms available

Offline mode of TelCal Goal : Exeute the data reduction off-line using the science data produced (the asdm dataset) Python interface of the C++ modules of TelCal (Engines and AsdmReader) Provide tools (plots) to test the validity of the calibration Default mode for Holography, AntennaPositions and PointingModel Also available for the other calibrations: PhaseCal, PhaseCurve, Pointing, Focus, BandPass, Atmosphere, Skydip

Offline mode : user interface TelCal within Casa : Casa tasks –Use the Casa formalism (XML wrapper interface). – Offline tasks asdmplot : Plot the data from an ASDM dataset (visibilities,totalpower, WVR data…) asdmlist : List the content of an ASDM dataset tc_antpos : Process an antenna position calibration and plot the result –Online tasks tc_atmosphere, tc_wvr tc_delay, tc_bandpass, tc_sidebandratio tc_focus, tc_pointing tc_amplical, tc_phasecal, tc_phasecurve

Calibration examples Examples : –Atmosphere calibration –Pointing, Focus –Delay measurements, Antenna Positions –PhaseCal, Phase Curve –BandPass –Holography See: Telescope Calibration User Guide from Robert Lucas

TotalPower pointing (cross scan) Single-Dish pointing Cross-scan Totalpower data Source: Saturn Results : DV01 : (-0.73, -1.66) arcsec PM03: (1.15,-1.69) arcsec Red : measured points Green : fitted curve Blue : fitted points OSF: 06/07/2009