GPS弱信号的高灵敏度捕获算法

摘要

为提高弱信号环境下全球定位系统(global positioning system,GPS)捕获的灵敏度,需进行累积提高增益.在分析传统相干累积和非相干累积算法的基础上,研究了一种基于快速傅里叶变换(fast fourier transformation,FFT)的差分相干累积方法.并采用蒙特卡罗仿真,分析了载噪比(carrier to noise ratio,C/N0)、累加次数、相干累积时间的选择对非相干算法和差分相干算法性能的影响.仿真结果表明,较传统非相干法,研究的差分相干法用于检测弱信号时具有明显的性能优势,信号检测增益最多可增加约1.8 dB,充分说明了差分相干在高灵敏度捕获中的优势.%To enhance the sensitivity of global positioning system (GPS) signal acquisition in weak signal environment,a long integration time is needed to improve the gain. Two conventional high-sensitivity acquisition methods which are coherent integration and non-coherent integration are studied in this paper. Based on the fast Fourier transform (FFT) ,differential coherent integration is adopted after the coherent integration for the acquisition of GPS weak signal. Finally the influence of the carrier to noise ratio(C/N0 ) ,accumulation times and coherent integration time on the performance of the non-coherent integration method and the differential coherent integration method is compared by using the Monter Carlo simulation. The simulation results show that the algorithm researched in this paper provides a detection gain improvement over the noncoherent integration method approximately 1.8 dB,which means the differential coherent integration method has better performance than the traditional non-coherent integration method.