Background+on+the+ALMA+Phasing+Project · 2016. 5. 4. · Maser VLBI Phasing Correlator: Control Central Electronics Central Variable Reference Photonic LO 2 bits/sample Each Quadrant:

•  Background on the ALMA Phasing Project – Delivers an ALMA Phasing System to allow – All the antenna signals to be combined to allow – ALMA to join in 3mm & 1mm VLBI networks

•  Current Status & Near Future •  Cycle 5/6 Development •  OpKons to move beyond that

Overview of the talk

May 3, 2016 G. Crew, the ALMA Phasing System

General Acknowledgement to the great many people who have brought us to this point

2

Project Timeline and Milestones

•  Fall 2011: Project incepKon •  November 2012: Preliminary Design Review & ALMA Board Approval •  May 2013: CriKcal Design Review •  January 2014: IniKal phasing system (R10.6) and first VLBI recordings •  June 2014: InstallaKon of Hydrogen Maser •  July 2014: Switchover of ALMA to Maser •  October 2014: CompleKon of Hardware installaKon; So\ware verificaKon of all major

features completed (R2014.4) •  November 2014: Hydrogen Maser Acceptance Review •  December 2014: Hardware Acceptance Review (CondiKonal Pass) •  January 2015: Start of Commissioning and Science VerificaKon (R2014.6) •  March 2015: First InterconKnental Fringes with Phased System •  July/August 2015: Band 3/Band 6 VLBI Commissioning •  October 2015: “Incremental S/W Acceptance” (Cycle 3) •  December 2015: DemonstraKon of SB operaKon •  April 2016: Band 6 SB-‐driven VLBI ObservaKon (R2015.8) •  Sept 2016: Cycle 4 Acceptance •  Oct 2016 – Sep 2017: Cycle 4

May 3, 2016 G. Crew, the ALMA Phasing System 3

Maser

VLBI

Phasing

Correlator: Control

Central Electronics

Central Variable Reference

Photonic LO

2 bits/sample

Each Quadrant:

2Pol x 32ch x 62.5MHz

Data Rate: 16 Gb/s

128 LVDS Pairs

Correlator: Baseline

H Maser

EPC

CDP Computer Cluster

Fast Phase Solver

TelCal Computer

Slow Phase Solver and Monitor

Fiber DEMUX

Fiber MUX

Correlator: Station

Front End

Samplers, WVR

Optical Fiber Tx

Antenna

Phasing Interface Card

GPS

Alma Observing Blocks

Connects to all sub−systemsALMA Control System

Correlator Hardware Protocols

TFB Commanding

Correlator Card (CC)

Cross Correlation

Form VLBI Sum

Delay to align VLBI sum

VLBI sum antenna mask

Scaling of VLBI Sum

Route data to corr cards

VLBI sum input

Correlator Interface Card (CIC)

Long Term Accum/Final Add

∆φ Phase Corrections (Fast)

Monitors phasing efficiency by

correlating sum with reference

to calculate phase corrections

Uses source model parameters

∆φ Phase Corrections (Slow)

Scaling of VLBI sum

Delay control for CIC input

Interface with Phasing Calculators

Synchronization command

Time setting

Monitor GPS−Maser Drift

VLBI Scheduler

Control of VLBI Recorders

Control of CIC VLBI sum input

Control of CC:

VLBI antenna sum mask

Control of TFB:

VLBI Observing Block

Sends Parameters to TelCal Computer

Control of Phasing Interace Cards:

Control of Source Model Monitor

Phase offsets

Station Card

Geometric Delay

Optical Fiber Rx/Demux

Form 32 x 62.5 MHz slices

Tunable Filterbank Card (TFB)

Phase shift each slice 2 Cards per Quadrant

8 x 10 GbE

Phased Sum Data

10 GbE Packetization

Synchronization

PPS/Clock Monitor

VDIF Formatting

Baseline Visibilities

Generate Channel Averages

AOS (high site)

OSF (low site)

OSF (low site)

8 x 10 GbE

VLBI 16 Gbps Recorders

Tu

nab

le F

ilte

rban

k C

om

man

ds

10 MHz

1 PPS

5 MHz

CRG: 125 MHz, &c

MASER_V_GPS_COUNTER

APP System Block Diagram

FuncKonal area

Exists New

Timing

Back End

Phase sum

Phase soluKon

Observing block


APP So\ware Block Diagram

PI

Control Device

Hardware Side

Control Device

Correlator

Scheduler

Operator

Correlator

TelCal

ALMA Operator Display

VOM Schedule Block

Maser−GPS Monitor

Maser

AOSTiming

VLBI Recorder

VLBI OFLS

LTA Protocol

PIC Control

VLBI Observing Mode (VOM)

Phase Solver

Efficiency Monitor

Source Modeler

VEX2VOM Translator

VLBI Observation Status

VLBI Hardware Status

TelCal Results Display

CCC Phase Updates

VOM Observing ScriptVOM Configuration Data

VEX file

Configures ALMA for VLBIRuns the experiment

Phase Update (TFB)

Data Pathways

Prepares ALMA Sched BlockIngests VEX & PI intents

Maser

VLBIController

InterferometryController

PhasingController

Phasing

VLBI

Data

ChannelAverage

PhasingCorrections

FuncKonal area

Exists New


VLBI Observing Mode, new in Cycle 4


Standard Interferometry

Standard VLBI

Standard Single Dish

Standard Solar (is also new in Cycle 4)

6

The VLBI inherits from Interferometry to pull in antenna control, &c....

Some APS Nomenclature

•  Scan Hierarchy –  VLBI Scans refer to the recordings –  Correlator Sub Scans –  “Slow” Scan phase correcKons from TelCal –  “Fast” phase correcKons made by CORR

•  DisKnguished Antennas –  Reference Antenna –  Phased Antennas (N of these) –  The “Analog” Sum Antenna –  Comparison Antennas

•  (<Sum . Comp>) / (<Ref . Comp>) ~ Sqrt(N)


Scan Strategy

Phased Phased PhasedUnphased ∆ ∆ ∆

TFB Commands

. . .

WVR Data

. . .

. . .

TelCal Solving

Correlator Scan Sequence

. . .

. . .

VLBI Scan Record On

Time

Slow Loop

Fast Loop


TelCal Phasing Engine

Active!

Source'2'VLBI scan

ALMA scan (= subscan)

TelCal activity

Phasing solution validity

flagged data interval

Time

Active! Active!Active! Active! Active! Active! Active!

Source'1'

G. Crew, the ALMA Phasing System

TelCalResults*

Engines*

Libraries*

TelCalPublisher*

GetTelCalResult*

Control*

DataCapture*

Correlator*

Bulk*

TelCalDataManager*

ParameterTuning*

ReceivingDataManager*ReceivingDataManager*

ReceivingDataManager*

use

Bulk data

Meta data

•  TelCal driven by scan intents •  Least-‐squares-‐fijer exists in a

TelCal library •  On each scan the engine solves

for slow phase (and delay) errors which remain a\er fast WVR correcKons

•  Publishes (new) ASDM table •  Provides feedback on quality

(phasing efficiency, opKmal antenna choices, &c.)

Data are flagged relaKve to phase adjustments for the

benefit of fimng engine

May 3, 2016 9

Phase CorrecKons from TelCal


This scan had CM, DA, DV and PM antennas

INPUT OUTPUT

General Phasing Sequence

«CORBAInterface»:SingleFieldInterferometryObservingMode

«CORBAInterface»:ObservationControl

Operator

Scheduling «CORBAInterface»:AutomaticArray2

«CORBAInterfa...:ParameterTuning

«CORBAInterfa...:GetTelCalResults

«CORBAInterface»:ReceivingDataManager

«CORBAInterfa...:ScriptExecutor

«CORBAInterfa...:DataCapturer

«CORBAInterfa...:ExecutionState

callback

«CORBAInte...:SkyDelayServer

corrSubscanSeqCalback

createArray()

startSB()

observeNow(sbId, sessionId)

runObservationScriptAsync(script, callback)

beginExecution()

startSB(arrayName, startTime)

ExecBlockStarted()

«event»

getSFIOffshoot() :SingleFieldInterferometryObservingMode

setAppSumAntenna(location, cableDelay)

setAppParameters(sourceModel, algorithm)

setSubArray(subarrayId, antennaList, bdStreamInfo)

setAppParameters(subarrayId, mask, refAntenna, algorithmMode)

doScanSequence(ScanSpecSeq, SimpleCallback) :Time

wait()

beginScan(ScanIntentDataSeq)

ScanStarted()

«event»parseIntents()

sendAppParametersData(mask, refAntenna)

getReconfigurationTimes(subarrayId, calibrations, durations) :SubscanTimingSeq

compute timings()

startSubscanSequence(subarrayId, startTime, executeBlockID, executeBlockNumber, subscanInfos, callback)

startSubscanSequence(arrayName, subscanIntents)

binary data()

report(status)

sendSubScanCorrelatorData(arrayId, subscanNumber, data)

ScanProcessedEvent()

«event»

getFinalMetaDataQL(scanNum) :ASDMDataSetIDL

publishAppResults()

isAppPhaseResultAvailable()

AppPhaseReducedEvent()

«event»

getAppPhaseResult()


«event»getAppPhaseResult()

setAppSlow(subarrayId, mask, refAntenna, phaseSeq)

sendAppParametersData(mask, refAntenna)

binary data()

report(status)

report()


Too much detail to present—see the Design Document

Time

Different So\ware Components

Correlator Phasing Sequence

Corr HW «CORBAInte...:Node

«CORBAInte...:Master

PhasingCallback

«CORBAInterf...:ObservationControl


consider one ALMA subscan

loop for each ALMA scan

loop fast phase corrections


setSubArray(array, bddStreamInfo)

setArray(array)

setAppParameters(subarrayId, mask, refAntenna)

configureLTA(mask, scalingData)

setupPIC(VDIFchannels)

setPICcontrol()

setPICheader()

doAppScanSequence(...)

setAppScanParameters(algorithmMode)setAppMode(algorithmMode)

setAppMode(algorithmMode)

beginScan(intents)

getReconfigurationTimes(subarrayId, calibrations,durations) :SubscanTimingSeq

computeTimings()

startSubscanSequence(subarrayId, startTime, executeBlockID,executeBlockNumber, subscanInfos, callback)

startSubscanSequence(arrayId, startTime, executeBlockID,executeBlockNumber, subscanInfos, callback)

startSubscanSequence(arrayId, startTime, subscanInfos)configureLTA(sumSwitch=on)

flagDataInvalid()subscanStarted()

slowPhaseLoop()

setAppSlow(subarrayId, mask, refAntenna, phaseSeq, interval) :timestamp

configureLTA(mask, scalingData)

applyTFBPhases(phaseSeq)

setAppSlow(arrayId, phaseSeq, timestamp, cb)

setAppSlow(arrayId, phaseSeq, timestamp)

flagDataValid()

calculatePhases()updatePhases(phaseSeq)

updatePhases(phaseSeq)

applyTFBPases(phaseSeq)

report(status)


TelCal Phasing Sequence

«CORBAInter...:GetTelCalResults

«CORBAInterface»:ReceivingDataManager

«CORBAInterf...:ParameterTuning

«CORBAInte...:DataCapturer


«CORBAInte...:ExecutionState

«CORBAInterf...:ObservationControl

consider first ALMA scan

loop for each ALMA scan

consider asynchronos processing

Phase processing done.


setAppParameters(subarrayId, mask, refAntenna)

sendAppParametersData(mask, refAntenna, timestamp)

doAppScanSequence(...)

setAppScanParameter(sourceModel, algorithmMode)

setAppScanParameters(sourceModel, algorithmMode)

beginScan(intents)ScanStarted()

«event»

parseIntents()

startSubscanSequence(arrayName, subscanIntents)


report(status)



«event»

getFinalMetaDataQL(scanNum) :ASDMDataSetIDL

calculatePhaseResults()

beginScan(intents)

ScanStarted()

«event»startSubscanSequence(arrayName, subscanIntents)


publishAppResults()

isAppPhaseResultAvailable()

AppPhasedReducedEvent()

«event»


«event»

getAppPhaseResult()

getAppPhaseResult() :AppPhaseResultgetAppPhaseResult() :AppPhaseResult

analyzePhaseResults()

setAppSlow(subarrayId, mask, refAntenna, phaseSeq, interval) :timestamp

sendAppParametersData(mask, refAntenna, timestamp)

*fastPhaseLoop()

report(status)



«event»May 3, 2016 G. Crew, the ALMA Phasing System 13

Project Timeline and Milestones

•  Fall 2011: Project incepKon •  November 2012: Preliminary Design Review & ALMA Board Approval •  May 2013: CriKcal Design Review •  January 2014: IniKal phasing system (R10.6) and first VLBI recordings •  June 2014: InstallaKon of Hydrogen Maser •  July 2014: Switchover of ALMA to Maser •  October 2014: CompleKon of Hardware installaKon; So\ware verificaKon of all major

features completed (R2014.4) •  November 2014: Hydrogen Maser Acceptance Review •  December 2014: Hardware Acceptance Review (CondiKonal Pass) •  January 2015: Start of Commissioning and Science VerificaKon (R2014.6) •  March 2015: First InterconKnental Fringes with Phased System •  July/August 2015: Band 3/Band 6 VLBI Commissioning •  October 2015: “Incremental S/W Acceptance” (Cycle 3) •  December 2015: DemonstraKon of SB operaKon •  April 2016: Band 6 SB-‐driven VLBI ObservaKon (R2015.8) •  Sept 2016: Cycle 4 Acceptance •  Oct 2016 – Sep 2017: Cycle 4


We are here

Immediate Next Steps

•  Correlate and analyze April 1mm session – “Sample” Cycle4 1mm observaKon – Bring PolConvert to OperaKonal Readiness

•  SKll need to capture 3mm session (June/July?) – DemonstraKng that VEX2VOM’d phase2 schedule blocks play nicely with the Archive

– Need to finalize VLBI operaKonal details (reconciling VLBI scheduling with ALMA)

•  Ready for Cycle 4, except for – Final details for operaKng the VLBI arrays, and…


ICT-‐5401: Aug 27th phasing (25 ant. phased)


March 23, 2016 (VLBI Regression Test)


Appear to have resolved some things


ICT-‐7128 remains

18

Amp v Time for <Sum . Comp> for 9 comparison antennas

Working on ICT-‐7218 (side discussion…)


CASA Plots of Real v Imag visibiliKes for 6 phased antennas during one scan, colors by integraKon

DGCK fine delays as logged at several of these antennas, integrated, linear fit subtracted

Colors bars correspond to sub-‐scans reported by Controller or CCC

Things which follow the sine qua non for Cycle 4

•  Le\-‐over from APP – GUI (Python version) – Source Modeler (could appear as needed)

•  ADF Cycle 3 Study (Majhews): – Turn Baseband Delay back on in CDP – Mismatched Channel OpKons – Band 7 (see next slide) – Analysis Support for Observers

•  ADF Cycle 3 Study (Cordes): – Using the APS for pulsar work


Second Band7 Session (Aug 2015) Amplitude of small array on (3 sources)

1337-‐129, 3c279, 1337-‐129


Example DA58 (reference antenna) & DV11

We used 8 channel averages; We can use 16 or 32 on bright sources (phased in most scans; un-‐phased for some)

Delay when un-‐phased

Delay when phased

15

Bejer Baseband Delay Fix


Frequency

CDP Residual Delay CorrecKon normally also includes the much larger Baseband delay

Cycle 5/6 under Discussion (at OBSMODE)

•  Implement the Delay Fix –  TelCal looks up Baseband Delays the same way that the CDP does and undoes the CDP work prior to calculaKng phases

–  Requires some changes to the phase pack/unpack library •  Remove the current 500 mJy restricKon •  Add a Spectral Line mode for VLBI – Mostly a data-‐rate, OT limitaKon –  Spectral averaging puts line details into oblivion –  Spectral Setup is currently aimed at conKnuum – We should be using the FDM Frequency agility [or MulK-‐resoluKon modes (see Ray/Rich talks)].


Beyond Cycle 6: Sub-‐arrays

VLBI does not play well with sub-‐arrays. •  OperaKonal: required “start” Kme •  There is only one “sum” antenna •  There is only one LTA “sum” antenna switch •  PICs are not owned by any sub-‐array •  Slow phasing adjustments assume no other CAN bus traffic

•  WVR correcKons assumes a single array •  hjps://ictwiki.alma.cl/twiki/bin/view/Control/AppMulKSubarrays •  hjps://ictwiki.alma.cl/twiki/bin/view/Control/AppPhase2TaskIdeas


Documents

Background+on+the+ALMA+Phasing+Project · 2016. 5. 4. · Maser VLBI Phasing Correlator: Control Central Electronics Central Variable Reference Photonic LO 2 bits/sample Each Quadrant: