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Multiband passive synthetic aperture imaging system

A comprehensive aperture and imaging system technology, applied in the system field, can solve the problems of increasing system weight and complexity, a large number of antennas, etc.

Inactive Publication Date: 2011-04-06
BEIHANG UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

In practical applications, in order to obtain sufficient coverage of spatial frequency sampling to achieve the purpose of imaging, a large number of antennas is required, which will greatly increase the weight and complexity of the system

Method used

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  • Multiband passive synthetic aperture imaging system

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Embodiment Construction

[0022] In the implementation case of the present invention, adopt such as image 3 The optimized eight-unit circular array structure is shown as a multi-band antenna array 1 containing four operating frequency bands, and its position distribution is as follows image 3 shown in . The center frequencies of the four working frequency bands of the multi-band antenna array are 1.4GHz, 2.8GHz, 4.2GHz and 5.6GHz respectively. Figure 4 It shows the frequency sampling distribution of the field of view corresponding to the multi-band antenna array: the circle points on the way correspond to image 3 The spatial frequency sampling distribution of the field of view of the corresponding single-band antenna array, while the spatial frequency sampling of the four-band multi-band antenna array in this implementation case includes not only circle points, but also all solid points. It can be seen that the spatial frequency coverage effect is greatly improved It can also be seen that the cut...

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Abstract

The invention provides a new multiband passive synthetic aperture imaging system. Spatial frequency sampling coverage of the imaging system is greatly improved by a multiband technology, thereby realizing high-resolution and high-quality imaging in real time while working in a radio-frequency microwave band. In the invention, signals radiated and scattered by a target are received by a multiband antenna array, and enters an array receiver; the signals are mixed with local oscillation signals output by an ultra wideband tunable YIG (yttrium iron garnet) oscillator; the mixed output signals are filtered to acquire intermediate frequency signals; the intermediate frequency signals are output after intermediate frequency amplification; and finally, after passing through an analog-to-digital conversion acquisition card, the signals are input into a signal processor for carrying out pairwise correlation calculation to acquire spatial frequency sampling of a field of view. By tuning the YIG oscillator by using the multiband antenna array, visibility functions of different frequency bands can be acquired, thereby greatly improving the coverage effect of target spatial frequency sampling and the imaging quality.

Description

technical field [0001] The present invention relates to a multi-band passive synthetic aperture imaging system, mainly by making full use of signals of different frequency bands received by a multi-band antenna array to achieve more sufficient spatial frequency sampling coverage with a relatively small number of antennas, and finally achieve the purpose of imaging kind of system. Background technique [0002] Any object above absolute zero will radiate electromagnetic waves. Passive imaging detection uses the electromagnetic radiation of the detected object and uses a specific inversion algorithm to obtain the target's brightness temperature map. For passive imaging systems, synthetic aperture technology is an effective method to obtain high spatial imaging resolution. This technology uses several small-sized and light-weight small-aperture antennas to arrange them into a sparse aperture array according to the shape and size of the carrier, according to the minimum redundan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S13/90
Inventor 何云涛江月松张跃东刘丽
Owner BEIHANG UNIV
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