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Wide area observation method of sector scanning

A fan-scan, wide-area technology, applied in the radar field, can solve the problem of inability to realize fast wide-area observation, improve time resolution and observation efficiency, efficient two-dimensional wide-area observation, and reduce the difference in image azimuth resolution Effect

Inactive Publication Date: 2009-01-14
BEIHANG UNIV
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AI Technical Summary

Problems solved by technology

SARs equipped with these three conventional scanning modes on slow platforms cannot achieve fast wide-area observations, and a scanning mode is needed to achieve efficient wide-area observations by slow platform SARs

Method used

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  • Wide area observation method of sector scanning
  • Wide area observation method of sector scanning
  • Wide area observation method of sector scanning

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Embodiment 1

[0062] Azimuth resolution δ is achieved on a platform with a height H of 15km and a flight speed v of 30m / s a max is 5m, the central viewing angle θ L Imaged in a 60° sector scan mode. Other parameters are shown in Table 1. The implementation method of sector scan mode SAR is specifically through the following steps:

[0063] Table 1 Main analysis parameters

[0064]

[0065] The implementation method of sector scan mode SAR is specifically through the following steps:

[0066] Step 1: According to the layout of the actual antenna TR components and the phased array antenna theory, the azimuth pattern of the antenna can be obtained when the azimuth is different, as shown in Figure 9a As shown, when the sweep angle is 25 degrees, a strong grating lobe of -17dB appears at the pointing angle of -80 degrees, and the strong grating lobe will make the ambiguity index worse; the main lobe offset is reduced to - 16.85 degrees, such as Figure 9b The intensity of the grating l...

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Abstract

The invention provides a sector scanning SAR wide observation method which leads a phased array antenna to regulate the orientation of an azimuth beam according to a sector angle and an angular velocity parameter and along impulses so as to lead the azimuth beam to rotate with a constant velocity according to the impulse emission direction in the scope of the sector angle and form a scanning beam to obtain an imaging zone resembling a sector annulus, and then emits a linear frequency-modulated signal and receives an echo signal so as to obtain a full image through a two-dimensional focusing process and a revising-splicing process. A visual angle is preserved hereabout a right side angle of the azimuth to form the imaging zone resembling the sector annulus so as to realize the azimuth high-effective wide observation; the azimuth beam is adopted to scan along the azimuth sector in the signal accessing process so as to enhance the azimuth observation efficiency of a classic strip mode in a low-velocity platform SAR load while guaranteeing a wide switch. The method can carry out the two-dimensional observation for a large area in a short time to enhance the time resolution and observation efficiency of azimuth, thus realizing the high effective two-dimensional wide observation.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a wide-area observation method for sector-scan SAR. Background technique [0002] For synthetic aperture radar sensors, quickly and effectively finding the target of interest can greatly enhance its application value. Having wide-area observation and surveillance capabilities is an important content in the design of platforms and SAR payloads. Since the azimuth resolution is equal to the ratio of the platform velocity to the Doppler bandwidth, for a slow platform, the movement velocity of the platform is low, and the same Doppler bandwidth can make the resolution value smaller, thereby obtaining a higher resolution; Usually the pulse repetition frequency is slightly larger than the Doppler bandwidth, so the slow platform SAR can still obtain high-resolution images with a lower pulse repetition frequency. The smaller the pulse repetition frequency, the longer the transmission puls...

Claims

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Application Information

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IPC IPC(8): G01S13/90
Inventor 陈杰孙兵周荫清李春升
Owner BEIHANG UNIV
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