基于GNSS(全球导航卫星系统)机会式信号发射源的成像探测方法，被称之为GNSS雷达，可全天候无盲区进行遥感探测，具有无需信号发射装置、隐蔽性强、成本低等优点，因而得到国内外广泛关注。但是在现阶段的研究中，还存在着伪随机码码元内多目标回波信号混叠、远距离小目标遥感成像效果不佳以及长时间合成孔径成像观测计算复杂度高等主要问题，导致了该技术在遥感中的应用受限。本项目从以下几方面开展研究：1.为提升多目标可区分度，拟提出区分码元内混叠距离向压缩信号的成像方法；2.为提升远距离小目标场景的成像增益，拟提出多卫星信号相干积分的成像方法；3.为减小合成孔径成像计算复杂度，拟研究合并冗余方位向采样点的成像方法；4.为验证所提出方法的有效性以及可靠性，拟通过基于地表反射物、船只以及飞机探测场景下的实测数据，分析比较提出方法在实地遥感中的效果。本项目的研究将促进GNSS技术在环境遥感领域的应用。

Passive Global Navigation Satellite System (GNSS)-based radar, known as GNSS-radar, can perform remote sensing surveillance with no blind area all day all weather. Since no radar transmitter is needed, the system has low cost budget and the receiver can be safely concealed. Thus it has been attracted by numbers of research interests in recent decade. However, based on the current relevant research, it still has the main problems as multi objects echo signal aliasing within one pseudorandom noise (PRN) code chip, low image signal-to-noise ratio (SNR) for long distance small objects surveillance and high computational complexity for long term synthetic aperture imaging. This project focuses on the following aspects: 1. To improve separability of multiple objects , the project plans to propose an imaging method that can distinguish aliased multiple range compressed signals within one PRN code chip；2. To improve imaging gain for small target surveillance at long distance, the project plans to propose an imaging method based on coherently integrating multiple GNSS satellites signals；3. To reduce computational complexity under synthetic aperture monitoring imaging scenario, the project plans to study the imaging method based on combining the redundant azimuth sampling point；4. This project plans to carry out experimental research to verify feasibility of the proposed methods under typical experimental remote sensing scenarios such as earth surface objects surveillance scenario, ferry surveillance scenario and aircraft surveillance scenario. This project can promote the implementations of GNSS signal in the field of remote sensing mechanism and the healthy development of GNSS technique.