Abstract:
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.