关键词: 无人飞行平台, 合成孔径雷达, Ka波段, 毫米波, 雷达成像, 线性调频变标算法

Abstract:

Unmanned Aerial Vechicle (UAV) is widely used in military investigation and attack, land and resources survey, disaster monitoring and other fields because of its advantages such as long stay time and easy maintenance. Synthetic aperture radar (SAR) is a kind of two-dimensional imaging radar, which can obtain radar images similar to optical images. It has the advantages of all-weather, high resolution, wide detection range and so on. It is one of the important loads of UAV. However, due to the relatively small space and load capacity of UAV, radar load must be small volume, light weight and low power consumption. Ka-band electromagnetic wave signal has the characteristics of short wavelength, wide bandwidth and small size of key microwave devices. It is suitable for high resolution miniature radar load. In 2015, the Institute of Electronics, Chinese Academy of Sciences, developed a kind of high resolution Ka-band synthetic aperture radar for small or medium UAV. The performance of the SAR was verified by flight test. In this paper, the key technologies of Ka-band SAR radar system are studied. The design scheme of radar system and key modules, the parameter of each working mode and real-time imaging algorithm are introduced. The radar weight is less than 10 Kg, and the peak power consumption is less than 100 W. It is suitable for small or light UAV. The high-resolution flight images obtained by the radar on light flight platform are displayed, and the performance of the images are analyzed. The experimental results show that the Ka-band SAR system can generate clear radar image and meets the design requirements. For example, the image resolution is better than 0.2 m and the detection distance is greater than 10 km..The rapid progress of microwave device technology represented by solid-state high power amplifier is the foundation of the success of this project. The project is a new attempt to develop Ka-band SAR and apply it to UAV. It also makes a useful exploration for the further development of Ka-band synthetic aperture radar and has important application value. The development of small Ka-band synthetic aperture radar in the future depends on the maturity of semiconductor technology and the improvement of the performance of Ka-band microwave devices. On the other hand, it also depends on the research of new style SAR which has high duty cycle and pulse agility, which can improve the average power of radar and solve the problem of ambiguity of detection range.

Key words: UAV, SAR, Ka-band, millimeter wave, radar Image, chirp-scaling algorithm