Real-time imaging processing system based on light and small unmanned aerial vehicle-mounted SAR

Abstract

The invention provides a real-time imaging processing system based on a light and small unmanned aerial vehicle-mounted SAR. Secondary up-conversion is carried out on an intermediate frequency excitation signal by adopting a first local oscillation signal and a second local oscillation signal group. The second local oscillation signals have a plurality of center frequencies, so that radio frequency excitation signals with different center frequencies can be obtained. Because the center frequencies are different, but the distance between a target and an SAR load is the same, the received radiofrequency signals are subjected to frequency conversion to obtain intermediate frequency echo signal groups with different phases, and each echo signal corresponds to one sub-band frequency spectrum,therefore, a plurality of sub-band frequency spectrums can be obtained through an intermediate frequency signal group, and then broadband signals with required bandwidths are obtained, so that high-resolution radar images are obtained. In addition, under the condition of electronic reactance, the center frequencies of the second local oscillation signals can be randomly valued, and the frequency hopping sequence can be flexibly adjusted, so that the radio frequency excitation signal hops within the required bandwidth range, the difficulty of detecting the signal sent by the equipment by interference equipment is increased, and the SAR anti-interference capability is improved.

Description

technical field [0001] The invention belongs to the field of UAV airborne SAR imaging technology, in particular to a real-time imaging processing system based on light and small unmanned aerial vehicle SAR. Background technique [0002] The small UAV platform has the characteristics of small size, low flying height and slow flying speed, and is easily affected by airflow disturbance. The stability of small UAVs is worse than that of large UAVs. At the same time, due to the slow flight speed of the UAV and the long synthetic aperture time in the azimuth direction, the error in the synthetic aperture time increases sharply, resulting in serious defocusing of the SAR imaging results. [0003] Traditional SAR motion error estimation methods all assume that the motion error frequency is low, the amplitude is small, and the synthetic aperture time is not long. In this case, the range migration error caused by the motion error can be basically ignored, and the motion error mainly ...

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This solution puts huge pressure on the image transmission equipment. In order to ensure the transmission rate and bit error rate requirements, the weight, volume and power consumpti

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