KVN
Recent Status of KJCC
for EAVN
Se-Jin Oh, Duk-Gyoo Roh, Jae-Hwan
Yeom, Dong-Kyu Jung, Chungsik Oh,Hyo-Ryoung Kim, Ju-Yeon Hwang
and NAOJ Corr. Team2018 VERA UM @ Mitaka, Sept. 25~26, 2018

Contents
vKJCC correlation status
vDevelopment status for wideband
vFuture works

Korea-Japan Correlation Center(KJCC)

Executive Board

Daejeon HW Correlator

DiFX SW Correlator on HPC

Correlation ModeaC1Bandwidth
[MHz]
256

C2128

22102432

C364

42102432

C432821024

32

C516162102432bW1

512 x 4band

42819264W2512 x 4band

1IFcx2Pd
2IFx1P

28192

64

W3

512 x 4band

2IFx2P

28192

64

Corr.
mode

Outputstreams#bits

12Outputdata rate[Mbps]
1024

a, Narrow band, b. Wideband, c. IF, d. Polarization

Clock rate
[MHz]
32

Correlation Status
SeasonObservation

Corr
Finished

Remain Corr

FITS
release2018A

88(w/6 geo)

71

1168

• Data copy for 2018A geodesy data was finished and diskpack wasalready delivered to MIZ.
• Data transportation for EAVN of SHAO (TIA) is currently conducted via
Internet vice versa.
• Each statistics correlation processing period is summarized in next page.

http://kjcc.kasi.re.kr

Correlation Status(KaVA overall)v Goal of Correlation Period§ 45days after obs.(which depends on media delivery)v KaVA Overall statistics Corr. periodv Obs : 62(8.28)
FITS release
after Obs

FITS release
after media
arrivalCorr.
Processing
after Obs

Corr.
Processing
after media
arrival

Average
Period(days)

54.4

24.1

49.6

19.3

Within45days afterObs

28/62(45.2%)

Within30days aftermedia arrival

40/62(64.5%)

47/62(75.8%)

54/62(87.1%)

Correlation Status(AGN WG
including EAVN)
v AGN WG statistics Corr. periodv Obs : 45(KaVA)/51(EAVN)(8.28)
FITS release
after Obs

FITS release
after media
arrivalCorr.
Processing
after Obs

Corr.
Processing
after media
arrival

Average
Period(days)

53.0/60.9

26.1/27.5

48.2/55.4

21.3/22

Within45days afterObs

18/45(40%)
18/51(35%)

Within30days after
media arrival

29/45(64.4%)
29/51(57.0%)
31/45(68.9%)
34/51(67%)

37/45(82.2%)
42/51(82%)

Correlation Status(Evolved Star WG)
v ES WG statistics Corr. periodv Obs : 9(8.28)
FITS release
after Obs

FITS release
after media
arrivalCorr.
Processing
after Obs

Corr.
Processing
after media
arrival

Average
Period(days)

46.0

17.6

40.6

12.1

Within45days afterObs

6/9(67%)

Within30days after
media arrival

8/9(89%)

9/9(100%)

9/9(100%)

Correlation Status(SFR WG)
v SFR WG statistics Corr. periodv Obs : 6(8.28)
FITS release
after Obs

FITS release
after media
arrivalCorr.
Processing
after Obs

Corr.
Processing
after media
arrival

Average
Period(days)

55.7

19.7

51.8

15.7

Within45days afterObs

3/6(50%)Within30days aftermedia arrival

3/6(50%)6/6(100%)

6/6(100%)

Correlation Status(Galactic
Astrometry WG)
v GA WG statistics Corr. periodv Obs : 2(8.28)
FITS release
after Obs

FITS release
after media
arrivalCorr.
Processing
after Obs

Corr.
Processing
after media
arrival

Average
Period(days)

119.0

22.5

115

18.5

Within45days afterObs

1/2(50%)Within30days after
media arrival

1/2(50%)2/2(100%)

2/2(100%)

KVN KREONET Status

100G

Data Transmissionv Data transmission from each Obs.
§ 4set STARDOM(RAIDBOX) server were prepared§ KaVA, EAVN observation data is transmitted• KVN only observation data(not KaVA, EAVN) is delivered via KREONET• From SHAO to KJCC, the EAVN data was transmitted, but speed is veryslow < 1Gbps.
• From MIZ to KJCC, the maximum 1.6Gbps speed is evaluated, which is
not connected to KREONET§ Mark5B/Mark6 data for KaVA will be transmitted soon.

EAVN(a17107a) EHT campaign
è EATING VLBI (Italy)

Bit-assign problem? àa18100a

POSSM
Before FRING
Auto-Corr Result

IRK-TAK

IRK-NOB

Bit-assign problem? àa18100a

POSSM
After FRING
Cross-Cor Result

IRK-TAK

IRK-NOB

Daejeon Correlator
Field Maintenance workv Close Maintenance work
§ In every year, manufacturer
visited KJCC.
§ This year : 8/27~8/31§ Field maintenance work wasdone without any problem.

OCTAD verification test
S.D

KYS

KUS

KTN

v 32 Gbps (8GHz BW) New Digital Backend
v 2017.08 : installed at KVN 3 stationsv A18118a : NRAO530(ref), SgrA*, M87 (by Byun-san, Yoon-san)v C4 mode (32MHz BW x 8IFs) by OCTAD was simultaneously
conducted and verified by comparing with current KVN DAS forcompatibility.
v The obtained delay rate and phase trend rate is mostly consistent
with current KVN DAS.
v In case of SNR, OCTAD obtained 20% higher than current KVN
DAS (due to difference sampling bit, OCTAD 3bit, ADS1K 2bit)

SNR (NRAO530)

KVN DAS

OCTAD

DelayKVN DASOCTAD

KVN Halcyon Recorder(KHR)(Specification)□ Target processor : Intel Xeon
□ Target board▪ Asrock X99 extreme11▪ DDR4 RAM 32GBytes▪ Broadcom BCM57711 NIC 10GbE PCIe
□ Operating System : FirmOS(like DOS)
10GbE NIC
▪ include schedulerPCIe▪ support multi-core▪ no filesystem▪ DRAM/NIC/SATA control directly(without device driver)□ Build environment: gcc, nasm(boot code)□ can make full resources and performance▪ recording speed 8.224Gbps(VDIF UDP)
▪ recordable capacity 90% of SATA HDD□ very cheap(Mainboard/CPU/RAM/NIC/Chassis)▪ around $5,000 without HDDs
Ø Upgraded to support MVMe (SSD) DDR4 RAM 32GBytes
installed(Support Maximum
128GBytes)

Intel Xeon multi-coreProcessor

SATA 10ports(OS disk 1ea & Recorddisks)

8Gbps recording test
v 8hrs, no data packet loss

OCTADàKHR recording

4set ADS1K+FILA10GàKHR recordingSW DFB development
v To speed up and support EAVN
v We are now developing and optimizing SW DFB basedon GPUSW DFB (r17289c 2Gbpsà1Gbps)
R17289c(1Gbps)

Preliminary result

Future works
v Data format alignment§ VERA : VDIF(octa)§ KVN : VSI, VDIF(general)§ KJCC : current all support è general VDIF
v Support binning-factor for CODA/FITSgen§ Reduce FITS file size for spectral-line
v SW Digital Filter Development§ Detail comparison work is expected§ Using Full data with SW DFB, the correlation will be scheduled