Second Italy-Ukraine meeting in Astronomy MULTIWAVELENGTH ASTROPHYSICS FROM RADIO TO GAMMA-RAYS Institute of Astronomy and Department of Astronomy and Space Informatics of V.N. Karazin Kharkiv National University September 25-27, 2018
CALIBRATION OF LARGE PHASED ANTENNA ARRAYS O.M. Ulyanov, V.V. Zakharenko, S.N. Yerin, A.I. Shevtsova, I.N. Bubnov, A.O. Skoryk, P.L. Tokarsky, M.A. Sidorchuk, V.M. Lisachenko Institute of Radio Astronomy NAS of Ukraine, Mystetstv str. 4, Kharkov 61002, Ukraine,
[email protected],
[email protected],
[email protected] 25 – 27 September, 2018, Kharkov, Ukraine
PhMI NASU, Lviv
PGO NASU, Poltava
RT-32
IRA NASU, Kharkiv
NASU, Kyiv
RT-70 RT-22
Positions of the Ukrainian Radio Telescopes UTR-2, URAN 1-4, GURT into Ukraine 2
Geometry and Design of the UTR-2 “T” Shape; Frequency Range 8-33 MHz Total amount of elements - 2040 dipoles Resolution at frequency 25 MHz 30’ x 30’ Effective area at central frequency 150 000 m2
3
S
N
W 4
North arm of UTR-2 Radio Telescope collective area
W
E
S
Collective area of URAN-2 is 28 000 m2 (512 broadband cross dipoles).
Frequency range were Radio Astronomy was born
RFI superimposed with to the Galactic background spectrum as measured by UTR-2 during a) a day and b) a night on December 11, 2015. Integration time is ~ 100 sec and frequency resolution is 4 kHz.
Modernization of Amplification System of UTR-2
ФВ64
ФВ 6-4 К П С
К П С
К П Р ФВ
5-5
АУ 1
●
ФВ 3-7
ФВ 5-7
Calibration
Щ И Т
К К К
К М К
ФВ28
А У 2
А У 3
●
АУ 4 ФВ210 Б Р Space Л Beams (l)
А У3
К М К
ФВ811
1
2
Б Р 3Л
Spac e Bea ms
- Pulsar Portable Receiver (WF 2 x 1.5 MHz; 2 bits),
АУ 2
Щ И Т
Г Т Ш Д
- 60-channal receiver,
С К
ФВ410
А У А 4 Т
3. Digital Receivers (2000 …):
АУ 1
С К
Щ И Т
2. Commutators (1997-2004)
К П Р ФВ
5-5
Calibration
1. Array Amplification System (1988-1994)
АУ 4 4
●
WF Receiver (WF 2 x 7.5 MHz; 8 bits), 4 DSPZ (Sp; Corr; WF 16 bits) (2x8192; 4x8192; 15ns )
5
6
Block-Diagram of the UTR-2 Radio Telescope
9
Cable system of UTR-2
10
Huge Phase Shifters (left side)
11
Underground Calibration Office of UTR-2
12
13
Principles of the Analog Phasing of the Large Phasing Arrays Using Time Delay Lines and Compensating Attenuate
14
Principles of Pointing of LPA by Hypothetical Phase Shifter A - 2. (where A is the number of inputs; 22 is the number of positions in the sky)
m−2
m−1
m0
m1
15
Projection of the Celestial Coordinates to the (l, m) Plane
16
Phase Shifter 3-7 (left figure) and Two Phase Shifters 6-4 (right figure)
17
A Simple Model of the NS UTR-2 Array
18
Efficiency of the Hybrid Coupler 1 err err Pd = [ P1 + P 2 − 2 √ P 1⋅P2⋅cos( ϕ1 −ϕ2 ) ] 2
P2 (f ) ← |U˙ 2 ( f )|e i ϕ
2
|U˙ 1 (f )|e i ϕ → P1 (f )
1 err err Ps = [ P1 + P 2 + 2 √ P 1⋅P2⋅cos( ϕ1 −ϕ2 ) ] 2
1
19
Efficiency of Calibration Cables with Imitator of the 1 Stage UTR-2 Amplifier. Comparison of the Old and New Data Average 4 section 5 section 9 section data of 1971 year data of 2001 year
−24 −26
DB
−28 −30 −32 −34 −36 −38 10
15
20 25 Frequency, MHz
30
35
20
Efficiency of the Sub-Sections № 1, 4-8 of the NS Array (from Dipole Inputs to PhS 2-8 Outputs)
−24 −25
dB
−26 −27 −28 −29 −30 10
15
20 Frequency, MHz
25
30
21
Calibration Matrix of the NS UTR-2 Arm
5 0
dB
−5 −10 −15 −20 −25 −30 −35
0
5
10
15 20 Frequency, MHz
25
30
22
Accounting the Contribution of the Large Phase Shifters (PhS 8-11) to the Total Efficiency of the 1st and 8th Section of the NS arm 4 3 2
dB
1 0 −1 −2 −3 −4 10
15
20 Frequency, MHz
25
30 23
Measured phase-frequency characteristics of PhS 5-5
24
Calculation of phase-frequency characteristics of PhS 4-10
25
Pase Errors PhS 6-4
26
Efficiency of the Hybrid Coupler 1 err err Pd = [ P1 + P 2 − 2 √ P 1⋅P2⋅cos( ϕ1 −ϕ2 ) ] 2
P2 (f ) ← |U˙ 2 ( f )|e i ϕ
2
|U˙ 1 (f )|e i ϕ → P1 (f )
1 err err Ps = [ P1 + P 2 + 2 √ P 1⋅P2⋅cos( ϕ1 −ϕ2 ) ] 2
1
27
Total Efficiency of One Section of the EW array for Coherent Signals (all losses included)
28
Solution for the Galaxy Brightness Background Temperature n NS
NS
B (l , m , f , ε˙ )⋅GNG (f ) K
T bg (l , m , f , ε˙ ) =
AT NS k
N NS
⟨ K (f )⟩[ ∑ K (i , m=0, f )] NS KK
i=1
N NS
с NS 2
k η (l , m , f , ε˙ ) K 1 (f )[∑ K 2 (i, m , f )] NS
n NS
nNS
i =1
Spectral Flux Density of Point Sources for One Polarization NS bg
k (T (l , m, f )+T NS viz
S (l, m , f , ε˙ ) =
inp NS sn
QNS
(l ,m , f , ε˙ )+ ∑ T (l , m , f ))
NS eff
A (l , m , f , ε˙ )
s=1
sNS br
, 29
Solution for Point Source Registered by NS Array c NS
B (l , m , f , ε˙ )⋅N NS⋅G NG (f ) K
NS VIZ
S (l , m , f , ε˙ ) ≈
AT NS k N NS
NS KK
⟨ K (f )⟩
A eff (l ,m , f , ε˙ ) η (l ,m , f , ε˙ ) K 1 (f )[ ∑ K 2 (i , m, f )] NS
NS
c NS
c NS
i=1
Solution for Calibration of the North-South and West-East Arms in the Correlation Mode S0 VIZ
S (l ,m ,f , ε˙ ) ≈
|B
√A
NS eff
cCCF
(l ,m ,f , ε˙ )|⋅G NG (f )K WE eff
AT CCF k
⟨K
NS p
NS;WE KK
(f )⟩ √ N NS⋅N WE WE p
(l ,m ,f , ε˙ ) A (l ,m, f , ε˙ ) K (l ,m ,f , ε˙ )K (l ,m, f , ε˙ ) 30
Galaxy Brightnes Temperature
31
Galactic Background Brightness Temperature Map at 20 MHz
Sidorchuk M.A. et al. Large-scale structure of the Northern sky at decametric waves // Scientific Workshop – Astrophysics with E-LOFAR. 2008. Konovalenko A. et al. The modern radio astronomy network in Ukraine: UTR-2, URAN and GURT // Experimental Astronomy. 2016. Vol. 42, № 1. P. 11–48.
The radio emission from the Galaxy at 22 MHz R.S. Roger et al., Astron. Astrophys. Suppl. Ser. 137, 7–19 (1999)
33
Thank You !
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