Research And Realization Of Key Technology For Indoor And Outdoor Positioning Receiver

Due to the expansion of city scales, It is difficult to find a place in a big building. With the development of our society, it becomes people’s urgent demand to positioning accurately and arrival quickly. The National 863 theme project "The key technology and service demonstration of City indoor and outdoor high-precision positioning the navigation", construction of urban indoor outside the high-precision positioning service system, realize indoor and outdoor seamless positioning. This paper mainly studies the positioning receiver in the acquisition and Snapshot key technology.First of all, this paper proposes an acquisition algorithm based on parallel correlator. Compared with the time domain serial acquisition algorithm and fast parallel acquisition algorithm based on FFT, the algorithm can keep acquisition performance, furthermore greatly enhance the trapping efficiency, and reduces the implementation complexity. Parallel correlator, code phase acquisition, carrier frequency acquisition module of the algorithm, has been implemented by FPGA, can successfully acquisition the signal.At the same time, through the simulation of quantization bits using Matlab, the acquisition performance can be optimized. The simulation results show that, acquisition performance is best in the 8bit quantization. Acquisition performance and system resources occupied are considered. In addition, this paper analyzed acquisition performance using cross-correlation mitigation algorithm, IPDL (Idle Period Down Link) mechanism. Results show that these two algorithms can significantly improve the ability to acquisition.Finally, in the weak signal environment, this paper presents a method combining a tracking loop and Snapshot mode. It realizes positioning through combining Pseudo-code phase by snapshot and pseudo-range by tracking module. Among them, Pseudo-code phase by Snapshot, provide auxiliary reference for positioning and help to reduce multipath interference.Method and the proposed methods in this paper effectively improve the system positioning precision, low implementation complexity. They have very high practical value.