摘要 :
Owing to the decametric wavelength, large aperture antenna array is needed for high frequency (HF) ground radar to obtain high angular resolution with conventional beam forming (CBF); for the case of compact antenna or small apert...
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Owing to the decametric wavelength, large aperture antenna array is needed for high frequency (HF) ground radar to obtain high angular resolution with conventional beam forming (CBF); for the case of compact antenna or small aperture array, spatial super-resolution algorithms are used to get satisfactory angular resolution. Wuhan University's ocean state measuring and analyzing radar (OSMAR2000) is expected to real time extract ocean surface current, wave and surface wind at medium- and long-range. To obtain long-range (i.e. 200km) current mapping, radar frequency must be selected in the lower region of the HF band, e.g. 7.5MHz. Digital beam forming (DBF) is applied with the 120m-long phased array to determine the bearings of sea echo with 150 resolution for wave and wind extraction. The angular resolution is, however, too coarse for current mapping, especially when the ocean current detection range is as far as 200km. Consequently, a super-resolution ocean surface current algorithm based on multiple signal classification (MUSIC) is developed for OSMAR2000. The relative theory basis, processing procedure and preprocessing and post-processing associated with the algorithm are given in this paper. The comparison of OSMAR2000 measurements with the measurements from current meter and the Seasonde system shows the ocean surface current algorithm based on MUSIC for OSMAR2000 can meet the requirements of the project contract successfully.
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摘要 :
Owing to the decametric wavelength, a large aperture antenna array is needed for high frequency (HF) ground radar to obtain high angular resolution with conventional beam forming (CBF); for the case of a compact antenna or small a...
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Owing to the decametric wavelength, a large aperture antenna array is needed for high frequency (HF) ground radar to obtain high angular resolution with conventional beam forming (CBF); for the case of a compact antenna or small aperture array, spatial super-resolution algorithms are used to get satisfactory angular resolution. Wuhan University's ocean state measuring and analyzing radar (OSMAR2000) is expected to real-time extract ocean surface current, wave and surface wind information at medium-range and long-range. To obtain long-range (i.e. 200 km) current mapping, the radar frequency must be selected in the lower region of the HF band, e.g. 7.5 MHz. Digital beam forming (DBF) is applied with the 120 m-long phased array to determine the bearings of the sea echo with 15/spl deg/ resolution for wave and wind extraction. The angular resolution is, however, too coarse for current mapping, especially when the ocean current detection range is as far as 200 km. Consequently, a super-resolution ocean surface current algorithm based on multiple signal classification (MUSIC) is developed for OSMAR2000. The relative theory basis, processing procedure and preprocessing and postprocessing associated with the algorithm are given. The comparison of OSMAR2000 measurements with the measurements from a current meter and the Seasonde system shows the ocean surface current algorithm based on MUSIC for OSMAR2000 can meet the requirements of the project contract successfully.
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摘要 :
A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar(HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal co...
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A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar(HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal combined sequence of waveform parameters, the radar system should be designed based on software radio principle. In this paper we discuss a software defined HF radar system-OSMAR2003, and focus on design and implementation of waveform generate unit for it .The proposed waveform generation unit integrates a frequency synthesizer with low phase noise and high signal to noise rate and a re-configurable synchronization control unit. The design is started with examination of requirements of the waveform and then optimize architecture of the combination of the synthesizer technology to satisfy the system requirements. Followed is the FPGA(Field Programmable Logic Array) based synchro unit controlled by VXI-bus. The measurement shows that the transmitted signal can be synthesized quickly with phase noise less than -109 dBc/Hz at 1-kHz off carrier and spur suppression greater than 65 dBc,While the waveform parameters can be set by VXI-bus .The signal generate unit becomes an important part of the software defined HFSWR and field experiments provide the validity.
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摘要 :
A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar (HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal c...
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A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar (HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal combined sequence of waveform parameters, the radar system should be designed based on software radio principle. In this paper we discuss a software defined HF radar system-OSMAR2003, and focus on design and implementation of waveform generate unit for it. The proposed waveform generation unit integrates a frequency synthesizer with low phase noise and high signal to noise rate and a re-configurable synchronization control unit. The design is started with examination of requirements of the waveform and then optimize architecture of the combination of the synthesizer technology to satisfy the system requirements. Followed is the FPGA (field programmable logic array) based synchro unit controlled by VXI-bus. The measurement shows that the transmitted signal can be synthesized quickly with phase noise less than -109 dBc/Hz at 1-kHz off carrier and spur suppression greater than 65 dBc, While the waveform parameters can be set by VXI-bus. The signal generate unit becomes an important part of the software defined HFSWR and field experiments provide the validity.
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摘要 :
A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar(HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal co...
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A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar(HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal combined sequence of waveform parameters, the radar system should be designed based on software radio principle. In this paper we discuss a software defined HF radar system-OSMAR2003, and focus on design and implementation of waveform generate unit for it .The proposed waveform generation unit integrates a frequency synthesizer with low phase noise and high signal to noise rate and a re-configurable synchronization control unit. The design is started with examination of requirements of the waveform and then optimize architecture of the combination of the synthesizer technology to satisfy the system requirements. Followed is the FPGA(Field Programmable Logic Array) based synchro unit controlled by VXI-bus. The measurement shows that the transmitted signal can be synthesized quickly with phase noise less than -109 dBc/Hz at 1-kHz off carrier and spur suppression greater than 65 dBc,While the waveform parameters can be set by VXI-bus .The signal generate unit becomes an important part of the software defined HFSWR and field experiments provide the validity.
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摘要 :
A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar (HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal c...
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A new radio frequency waveform generate unit is presented for software-defined high frequency surface wave radar (HFSWR). Since HFSWR operates in congested band, to suppress interference and clutters, together obtain the optimal combined sequence of waveform parameters, the radar system should be designed based on software radio principle. In this paper we discuss a software defined HF radar system-OSMAR2003, and focus on design and implementation of waveform generate unit for it. The proposed waveform generation unit integrates a frequency synthesizer with low phase noise and high signal to noise rate and a re-configurable synchronization control unit. The design is started with examination of requirements of the waveform and then optimize architecture of the combination of the synthesizer technology to satisfy the system requirements. Followed is the FPGA (field programmable logic array) based synchro unit controlled by VXI-bus. The measurement shows that the transmitted signal can be synthesized quickly with phase noise less than -109 dBc/Hz at 1-kHz off carrier and spur suppression greater than 65 dBc, While the waveform parameters can be set by VXI-bus. The signal generate unit becomes an important part of the software defined HFSWR and field experiments provide the validity.
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摘要 :
The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency syn...
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The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency synthesizer architectures are presented, and their advantages and disadvantages are compared. The preferred synthesizer is based on an architecture supporting a flexible combination of direct synthesizer and DDS (direct digital synthesizer) techniques with a low frequency reference crystal oscillator. The benefit of this architecture is the generation of signals with low phase noise and low spurious level. The measured output spectrum and field experiments undertaken in Zhujiajian Island demonstrate successful frequency synthesis operation.
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摘要 :
The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency syn...
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The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency synthesizer architectures are presented, and their advantages and disadvantages are compared. The preferred synthesizer is based on an architecture supporting a flexible combination of direct synthesizer and DDS (direct digital synthesizer) techniques with a low frequency reference crystal oscillator. The benefit of this architecture is the generation of signals with low phase noise and low spurious level. The measured output spectrum and field experiments undertaken in Zhujiajian Island demonstrate successful frequency synthesis operation.
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摘要 :
In this paper the Design and realization of the synthesizer for high frequency radar--OSMAR2003 (Ocean State Measuring and Analyzing Radar) is proposed. To provide a 47.5MHz Local signal and 7MHz transmitting signal, two kinds of ...
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In this paper the Design and realization of the synthesizer for high frequency radar--OSMAR2003 (Ocean State Measuring and Analyzing Radar) is proposed. To provide a 47.5MHz Local signal and 7MHz transmitting signal, two kinds of frequency synthesizer architectures are presented, both the advantages and disadvantages of them are compared. The preference synthesizer is based on architecture supporting flexible combination of direct synthesizer and DDS (direct digital synthesizer) techniques with a low frequency reference crystal oscillator. The benefit of this architecture is generating signals with low phase noise and low spurious level. The measured output spectrum and the field experiments undertaken in Zhujiajian Island demonstrate successful frequency synthesis operation.
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摘要 :
The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency syn...
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The design and realization of a synthesizer for high frequency radar, OSMAR2003 (ocean state measuring and analyzing radar), is proposed. To provide a 47.5 MHz local signal and 7 MHz transmitting signal, two kinds of frequency synthesizer architectures are presented, and their advantages and disadvantages are compared. The preferred synthesizer is based on an architecture supporting a flexible combination of direct synthesizer and DDS (direct digital synthesizer) techniques with a low frequency reference crystal oscillator. The benefit of this architecture is the generation of signals with low phase noise and low spurious level. The measured output spectrum and field experiments undertaken in Zhujiajian Island demonstrate successful frequency synthesis operation.
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