GURT Subarray: Structure and Characteristics

Transcription

1 Institute of Radio Astronomy National Academy of Sciences of Ukraine Kharkiv, Ukraine Serge Yerin GURT Subarray: Structure and Characteristics Latvia, Jūrmala - Ventspils - Irbene December 5-6, 2018

2 Serge Yerin GURT Subarray: Structure and Characteristics Giant Ukrainian Radio Telescope (GURT) Frequency range: 8-80 MHz. Up to several hundreds of subarrays. 5 5 element subarrays. Subarray dimensions m. Interelement spacing 3.75 m. Subarray elements active dipoles. Total area up to 2 sq. km. 2 orthogonal polarizations of incoming waves. Analog beamforming at subarray stage. Digital beamforming at entire antenna array stage. Digital signal processing. Low cost of dipoles and subarrays. Easy radio telescope extension. Construction in UTR-2 territory.

3 Serge Yerin GURT Subarray: Structure and Characteristics GURT active antenna subarray

4 Serge Yerin GURT Subarray: Structure and Characteristics

5 Serge Yerin GURT Subarray: Structure and Characteristics GURT Real Subarray dx d y m h 1. 6 m ABC 1. 4 m 45

6 Serge Yerin GURT Subarray: Structure and Characteristics GURT equipment box

7 Serge Yerin GURT Subarray: Structure and Characteristics GURT Advanced Digital Receiver (ADR)

8 Serge Yerin GURT Subarray: Structure and Characteristics GURT Advanced Digital Receiver (ADR) Parameters ADR GURT Frequency band (MHz) 80 Number of freq. channels (tunable) Frequency resolution (khz) 4,8 Time resolution (ms) 2 ADC resolution (bits) 16 Dynamic range (db) 90 Input channels 2 On-line real-time possibilities Fast Fourier transform Yes Wave-form Yes Auto- and complex cross-spectra Yes Sum-Subtraction mode Yes Signals normalization yes Signals delay yes

9 Serge Yerin GURT Subarray: Structure and Characteristics GURT spectrum (day) RFI and galactic background of GURT subarray phased to zenith direction (December 11, 2014 at Local time)

10 Serge Yerin GURT Subarray: Structure and Characteristics GURT spectrum (night) RFI and galactic background of GURT subarray phased to zenith direction (December 11, 2014 at Local time)

11 Serge Yerin Galactic background diurnal change GURT Subarray: Structure and Characteristics Galactic background distribution map

12 Serge Yerin Galactic background diurnal change GURT Subarray: Structure and Characteristics Galactic background distribution map as seen by single GURT dipole

13 Serge Yerin Galactic background diurnal change GURT Subarray: Structure and Characteristics Galactic background distribution map as seen by single GURT dipole and by GURT subarray of 25 dipoles

14 Serge Yerin GURT Subarray: Structure and Characteristics GURT long term observations (zenith)

15 Serge Yerin GURT Subarray: Structure and Characteristics Phasing directions of GURT subarray U sin sin V sin cos

16 Serge Yerin GURT Subarray: Structure and Characteristics Phasing directions of GURT subarray U sin sin V sin cos

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18 Serge Yerin GURT Subarray: Structure and Characteristics GURT subarray mathematical model

19 Model of antenna array N n f n, 1, ),, ( x r r x r z j j d r d r A E AJ A J J J AJ J S S S S S * 1 1 t t t t 1 ) 2( E z A V J V V J J V J S S C ) ( ) ( ) (1 t t t k B T * 0 t t d BT k A Ar V k B partial radiation patterns of the antenna array normalized matrix of self and mutual impedances where and are normalized matrices of radiation and loss resistances, where Covariation matrix of spectral densities of noise waves, where is Boltzmann constant Scattering matrix Serge Yerin GURT Subarray: Structure and Characteristics

20 Serge Yerin GURT Subarray: Structure and Characteristics Model of the GURT subarray i 1 e j[ E ( E A) S y11] A S y21 N - current distribution A e 2 i e f( m, m ) 2 i e r i e - effective area F ( m m e e m m, ) i f(, ) i f(, ) - normalized antenna pattern i e r i e i e r i e - efficiency T C int k B - temperature of internal noise T ext T B i e r i e - temperature of external noise SND T ext T int - SND (Sky Noise Dominance) SEFD kbt A e B 1 1 SND SEFD (System Equivalent Flux Density) T B - sky brightness temperature

21 Serge Yerin GURT Subarray: Structure and Characteristics Noise tests 1) 2) 3)

22 Serge Yerin GURT Subarray: Structure and Characteristics Dipole noise tests and its SND One array element with open-circuited amplifier input, short-circuited amplifier input and connected to dipole arms Sky-noise dominance (in short circuited mode) for one dipole

23 Serge Yerin GURT Subarray: Structure and Characteristics GURT dipole noise calculations and measurements P. Tokarsky, A. Konovalenko, S. Yerin, Sensitivity of an Active Antenna Array Element for the Low-Frequency Radio Telescope GURT, IEEE Transactions on Antennas and Propagation, vol. 65, is. 9, p , DOI: /TAP

24 Serge Yerin GURT Subarray: Structure and Characteristics Subarray noise tests and its SND All array elements with open-circuited amplifiers inputs, short-circuited amplifiers inputs and connected to dipoles arms Sky-noise dominance (in short circuited mode) for the whole subarray

25 Serge Yerin GURT Subarray: Structure and Characteristics Subarray noise tests and its SND All array elements with open-circuited amplifiers inputs, short-circuited amplifiers inputs and connected to dipoles arms Sky-noise dominance (in short circuited mode) for the whole subarray

26 Serge Yerin GURT Subarray: Structure and Characteristics SND vs. SEFD S min K rec 2 k A e B T sys t f SEFD t f SND = T ext T int η efficiency of passive dipole; χ mismatch coefficient of passive dipole and antenna amplifier; G amplifier transmission coefficient (of the whole consequent signal path). T ext external noise temperature T int internal system noise temperature Section Dipole output Amplifier input Amplifier output A e ηa e χ ηa e Gχ ηa e T ext ηt bg χ ηt bg Gχ ηt bg T int 1 Gχ T amp 1 G T amp T amp ΔS min = ηa e 2 k B Δt Δf 1 Gχ T amp + ηt bg = ηa e 2 k B Δt Δf T int + T ext = ηa e 2 k B T ext Δt Δf 1 + T int T ext = 2 k B ηt bg ηa e Δt Δf SND = A e 2 k B T bg Δt Δf SND

27 Serge Yerin GURT Subarray: Structure and Characteristics GURT subarray noise calculations and measurements Close to zenith direction Close to horizon direction

28 Serge Yerin GURT Subarray: Structure and Characteristics GURT antenna subarray results E-plane H-plane Variation of subarray effective area vs. angle of wave coming

29 Serge Yerin GURT Subarray: Structure and Characteristics GURT Sky Noise Dominance (SND) P. Tokarsky, A. Konovalenko, S. Yerin, Sensitivity of an Active Antenna Array Element for the Low-Frequency Radio Telescope GURT, IEEE Transactions on Antennas and Propagation, vol. 65, is. 9, p , DOI: /TAP

30 Serge Yerin GURT Subarray: Structure and Characteristics GURT system equivalent flux density (SEFD)

31 North-South arm (1440 dipoles) Single subarray single linear polarization (25 dipoles)

32 North-South arm (1440 dipoles) Single subarray single linear polarization (25 dipoles)

33 North-South arm (1440 dipoles) Single subarray single linear polarization (25 dipoles)

34 North-South arm (1440 dipoles) Single subarray single linear polarization (25 dipoles)

35 NDA GURT

36 Serge Yerin GURT Subarray: Structure and Characteristics Advantages of cosmic radio sources observations with high sensitivity GURT subarray of 25 active elements Nançay Decametric array 72 antennas

37 Serge Yerin GURT Subarray: Structure and Characteristics Advantages of cosmic radio sources observations with high sensitivity GURT subarray of 25 active elements Nançay Decametric array 72 antennas

38 Serge Yerin GURT Subarray: Structure and Characteristics Advantages of cosmic radio sources observations with high sensitivity GURT subarray of 25 active elements Nançay Decametric array 72 antennas

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40 Serge Yerin GURT Subarray: Structure and Characteristics

41 Serge Yerin GURT Subarray: Structure and Characteristics

42 Serge Yerin GURT Subarray: Structure and Characteristics

43 Serge Yerin GURT Subarray: Structure and Characteristics Scintillations of 3С405 (Cyg A) source

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45 Serge Yerin GURT Subarray: Structure and Characteristics Pulsar observations with single GURT subarray Pulsar name DM, SNR Period, s Flux density, Jy pc /см 3 GURT Stovall / Izvekova B (160) 6370 (3190) B (150) 220 (110) 230 (120)* [61 MHz] B (600) 4160 (2080) B (640) 1870 (350)* [61 MHz] B (180) 450 (230) B (780) 4680 (2340) B (410) 770 (160)* [85 MHz] B (240) 1290 (350)* [61 MHz] B (740) 2330 (620)*[102.5 MHz] B (3000) 4710 (2360) B (90) 510 (250) B (1000) 2130 (1060) B (1550) 2220 (1110) B (1500) 2100 (430)* [61 MHz] B (140) 590 (290) B (380) (5050)

46 UTR-2 GURT subarray Serge Yerin GURT Subarray: Structure and Characteristics Averaged (4 hours) pulsar pulses В В В Results of observations of pulsars with GURT subarray and UTR-2 radio telescope in the mode of arms signal combining

47 Serge Yerin GURT Subarray: Structure and Characteristics Objects that can be studied with GURT subarray

48 Thank you for attention! Q & A

49 Serge Yerin GURT Subarray: Structure and Characteristics Our main publications on the topic Tokarsky P., Konovalenko, A., Yerin. S Sensitivity of an active antenna array element for the low-frequency radio telescope GURT. IEEE Transactions on Antenna and Propagation, 65(9), pp DOI: /TAP Konovalenko, A., Sodin, L., Zakharenko, V., Zarka, P., Ulyanov, O., Sidorchuk, M., Stepkin, S., Tokarsky, P., Melnik, V., Kalinichenko, N., Stanislavsky, A., et al The modern radio astronomy network in Ukraine: UTR-2, URAN and GURT. Experimental Astronomy, 42(1), pp DOI: /s x Zakharenko, V., Konovalenko, A., Zarka, P., Ulyanov, O., Sidorchuk, M., Stepkin, S., Koliadin, V., Kalinichenko, N., Stanislavsky, A., Dorovskyy, V., Shepelev, V., et al Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT. Journal of Astronomical Instrumentation, 5(04), p DOI: /S

50 Serge Yerin GURT Subarray: Structure and Characteristics

51 Serge Yerin GURT Subarray: Structure and Characteristics 51

52 GURT Subarray 10 MHz 40 MHz 70 MHz

53 53 53

54 LOFAR LBA 96 dipoles sparse array GURT 25 dipoles dense array 54

55 Раздел 2 Сравнение результатов моделирования и измерений шумовых характеристик антенного элемента ГУРТ 55

56 Раздел 2 Сравнение результатов моделирования и измерений шумовых характеристик субрешетки ГУРТ 56

57

58

59 Нормирование спектра (повышение контраста) до после 59

60 60

61 Нормирование спектра (до) 61

62 Нормирование спектра (после)

63 25 dipoles GURT subarray vs. GURT dipole in 0-80 MHz range 1 dipole

64 25 dipoles GURT subarray vs. GURT dipole in 0-80 MHz range 1 dipole

65 25 dipoles GURT subarray vs. GURT dipole in 8-33 MHz range 1 dipole

66 25 dipoles GURT subarray vs. UTR-2 North Arm in 8-33 MHz range 720 dipoles

67 512 dipoles (16 x 32) Rectangular configuration URAN-2 Full telescope vs. UTR-2 North Arm in 8-33 MHz range 720 dipoles (6 x 120) Almost linear array

68 Comparison of solar bursts received with GURT subarray, UTR-2 radio telescope and Nançay Decametric Array (France)

69 Studies of double pairs under the ionosphere cutoff Y. G. Shkuratov, et al., A twofold mission to the moon: Objectives and payloads, Acta Astronautica, In press, Available online. 69

70 Юпитер - Джуно, УТР-2, ГУРТ

71 You should analyze events in various time scales 6,5 hours / picture scale III II IV 71

72 You should analyze events in various time scales 22 minutes / picture scale III II 72

73 You should analyze events in various time scales 4 minutes / picture scale II 73

74 Секции УТР-2 ( 1 и 9) Радиотелескоп УТР-2 ( + / - ) Субрешетка ГУРТ Раздел 4 Совместные наблюдения пульсаров на ГУРТ и УТР-2 В В В

75 Раздел 4 Определение меры дисперсии усредненных импульсов пульсаров с помощью УТР-2 В В В

76 L i 0 m Control code: i 76

77 L i 0, 3 m Control code : i 77

78 L i 0, 6 m Control code : i

79 L i 0, 9 m Control code : , 3 0i 79 79

80 L i 1, 2 m Control code : i

81 L i 1, 5 m Control code : , 4 0i

82 L i 1, 8 m Control code : , 7 0i 82

83 L i 2, 1 m Control code : , 2 0i 83

84 L i 2, 4 m Control code : , 1 0i

85 Углы фазирования секции ГУРТ L22 0, 3 м min 1,518 нс Всего направлений фазирования в области реальных углов:

86 GURT control system

87 GURT New control system

88 GURT control system

89 GURT receiving equipment

90 GURT Advanced Digital Receiver (ADR) Low noise level and low spurious signals level providing the high linear dynamic range (~120dB) Maximal ADC sampling frequency 160MHz Maximal input signal frequency 180 MHz Permanent Absolute Time Synchronization of the output data with the ADC synchro pulse accuracy. Two modes of operation: waveform and spectrometer Storing of the waveform data from both channels (650Mb/s at sampling rate 160MHz) on the local data storing system during 4 hours. Controlled signal digitizing relative delay in the range of 0 to 0.8μs (with 8 picoseconds step) between two input channels. Calculation of spectrograms in both channels and cross-spectrograms between channels Averaging of the spectra and cross-spectra up to realizations (~7 s at sampling rate 160MHz) Network Client-Server architecture of the high level software which allows the remote full control of the ADR and on-the-fly monitoring of the received signal.

91 GURT Advanced Digital Receiver (ADR) Number of channels 2 Analog input bandwidth 180 MHz Input impedance 50 Ohm Input voltage ±1V ADC sampling frequency МHz ADC resolution 16 bits ADC intrinsic dynamic range 75 db SFDR (spurious free dynamic range) (16384 samples per FFT) 112 db Intrinsic noise level (16384 samples per FFT) -117 db FFT size 2048, 4096, 8192, 16384, and Output FFT samples resolution 32 bit Speed of processing 4800 complex FFT per second Count of averaged spectrums Selectable frequency band output Maximal data rate ( Waveform mode) Maximal data rate ( Spectrometer mode) with step of 1024 samples 650 MB/sec 85 MB/sec

92 GURT Advanced Digital Receiver (ADR) Parameters DSPZ UTR-2 ADR GURT Frequency band (MHz) Number of freq. channels (tunable) Frequency resolution (khz) 4 4,8 Time resolution (ms) 0,5 2 ADC resolution (bits) Dynamic range (db) Input channels 2 2 On-line real-time possibilities Fast Fourier transform yes Yes Wave-form (non limited resolutions) yes Yes Auto- and complex cross-spectra yes Yes Sum-Subtraction mode no Yes Signals normalization no yes Signals delay no yes 92