Research On Squint Imaging Algorithm Of Airborne SAR

Synthetic aperture radar (SAR) is a kind of microwave imaging system. It has significant status in microwave remote sensing field. SAR has whole day characteristics in imaging process and microwave is an electromagnetic wave, it has a strong transmission capacity. No matter what the weather is, it has little effect on the microwave. So the SAR also has all-weather imaging characteristics. Synthetic aperture radar image shows the advantages of two-dimensional high-resolution, it is now widely used in civilian areas and military areas.This article puts squint imaging algorithm of airborne SAR as the main research, in the imaging process the author mainly simulation research is RD algorithm and CS algorithm.The main part of the work carried out as following:First of all, the author introduces the value of squint imaging studies and theoretical signficance. The research reason mainly performance two aspects. On the one hand, the squint SAR beam steering is very flexible, it can improve the safety and hidden of carrier aircraft flying platform. On the other hand, squint SAR can be repeated imaging, the one imaging in front of target and re-imaging behind the target. It can be flexible to choice the imaging area.Secondly, the author discusses airborne SAR pulse compression techniques in detail. Basic on the theoretical and experimental, Linear Frequency Modulation signal and pulse compression signal is simulated respectively. Analysis the simulation graphs we know that the sidelobe will impact on image quality.Therefore eliminate the sidelobe is necessary. The author also from the resolution, sidelobe ratio, the doppler center frequency, doppler frequency, range migration these aspects talk about their impact on image quality.Thirdly, the author establish airborne squint SAR geometry model and echo signal model, then analysis the origin of the echo signal in detail, and the point target echo signal in different squint angle is simulated. The simulation graphics also were analyzed from the influence of squint angle and different shapes echo signal.Lastly, the author research airborne squint range doppler algorithm and CS algorithm.For the shortcomings of the original RD algorithm, the author proposes an improved RDalgorithm for meeting the requirement of high-resolution airborne squint SAR. This improved algorithm can effectively eliminate the sidelobe interference. This improved algorithm compared with the original RD algorithm and CS algorithm through different point target and flight data. The simulation can prove the feasibility and effectiveness of the improved algorithm, it image can achieve satisfactory results.