Zeng Zhangfan, Shi Zhiming, Xing Sainan, Pan Yongcai
School of Computer Science and Information Engineering, Hubei University, Wuhan 430062, China.
Sensors (Basel). 2019 Apr 26;19(9):1965. doi: 10.3390/s19091965.
A Geo-Stationary GNSS-based Bistatic Forward-Looking Synthetic Aperture Radar (GeoSta-GNSS-BFLSAR) system is a particular kind of passive bistatic SAR system. In this system, a geo-stationary GNSS is used as the transmitter, while the receiver is deployed on a moving aircraft, which travels towards a target in a straight line. It is expected that such a radar system has potential for self-landing, self-navigation and battlefield information acquisition applications, etc. Up to now, little information from a research perspective can be found about GeoSta-GNSS-BFLSAR systems. To address this information gap, this paper proposes a preliminary image formation algorithm for GeoSta-GNSS-BFLSAR. The full details of the mathematical derivation are given. It is highlighted that, to overcome the long dwell time and spatial variance of GeoSta-GNSS-BFLSAR, a modified migration correction factor must be designed. In addition, the system performances and technical limitations of GeoSta-GNSS-BFLSAR such as focusing depth and spatial resolution are analytically discussed. In the end, a set of simulations including the image formation algorithm, focusing depth and spatial resolution were conducted for verification. It is demonstrated that the focusing performances of the proposed algorithm have a high level of similarity with the theoretical counterparts. This article thus proves the feasibility of GeoSta-GNSS-BFLSAR systems from a simulation level and establishes a foundation for the real applications of such a radar scheme in the future.
基于地球静止全球导航卫星系统的双基地前视合成孔径雷达(GeoSta-GNSS-BFLSAR)系统是一种特殊的无源双基地合成孔径雷达系统。在该系统中,地球静止全球导航卫星系统用作发射机,而接收机部署在一架直线飞向目标的移动飞机上。预计这样的雷达系统在自动着陆、自主导航和战场信息获取等应用方面具有潜力。到目前为止,从研究角度来看,关于GeoSta-GNSS-BFLSAR系统的信息很少。为了填补这一信息空白,本文提出了一种针对GeoSta-GNSS-BFLSAR的初步成像算法。给出了数学推导的全部细节。需要强调的是,为了克服GeoSta-GNSS-BFLSAR的长驻留时间和空间变化,必须设计一个修正的偏移校正因子。此外,还对GeoSta-GNSS-BFLSAR的系统性能和技术局限性,如聚焦深度和空间分辨率进行了分析讨论。最后,进行了一组包括成像算法、聚焦深度和空间分辨率的仿真以进行验证。结果表明,所提算法的聚焦性能与理论结果具有高度相似性。本文从而从仿真层面证明了GeoSta-GNSS-BFLSAR系统的可行性,并为该雷达方案未来的实际应用奠定了基础。