基于铱星机会信号的定位技术

全球导航卫星系统（GNSS）到达地球表面的信号弱，易受干扰，并且需要投入大量的基础设施，而机会信号可有效弥补这方面的不足。针对目前陆基机会信号（广播、数字电视和移动基站等）存在的覆盖性、可用性限制，提出了利用铱星系统实现天基机会信号定位。通过对铱星信号的通信体制进行深入研究，建立了瞬时多普勒定位数学模型，提出了利用铱星信号的单音信号获取多普勒频率信息，并结合轨道预测模型计算的卫星轨道信息实现铱星定位的方法。实测数据验证结果表明，利用实际铱星信号能够实现精度优于200 m的定位。研究成果对基于机会信号的定位技术的理论研究及应用具有参考意义。 

Positioning technology based on IRIDIUM signals of opportunity

The global navigation satellite system (GNSS) has a number of disadvantages such as weak signal strength on the ground, high infrastructure requirement and easy to be interfered, while signals of opportunity can make up these shortages. Space-based signals of opportunity positioning based on IRIDIUM is implemented for insufficiency of the coverage and availability of ground-based signals of opportunity such as FM, DTV and mobile base station. This paper realizes the function of positioning based on IRIDUM through combining Doppler shift information which is acquired with the tone signal of IRIDIUM signal and orbital information of satellite calculated from orbit prediction model after establishing mathematical model of instantaneous Doppler positioning by analyzing the communication system of IRIDIUM. The experimental results based on actual signal show that the positioning accuracy can reach better than 200 m. The research of this paper is significant in theoretical research and practice application of positioning technology based on signals of opportunity.