Research And Implementation Of Fast Acquisition Algorithm For Bedidou B3C Signal

Positioning receivers in China dependence on GPS for a long period,in performance and security by foreign restrictions,unable to meet the requirements of military and other fields.The Beidou second generation satellite navigation system based on passive positioning technology,with radio shielding.Researching the Beidou B3C(B3 frequency point short period ranging code)signal rapid capture methods can accelerate the development of China's navigation technology and have great practical significance and practical value to improve China's national defense power.According to the characteristics,modulation method and structure of the Beidou signal,the architecture and the capture method of the Beidou second generation navigation receiver are studied based on the research of the development of capturing technology in China and abroad.1.The acquisition performance of time-domain serial capture algorithm,FFT acquisition algorithm,matched filter acquisition algorithm and parallel maximum likelihood acquisition method are compared.This paper proposes a PMF-FFT acquisition algorithm which can realize two-dimensional searching in time domain and frequency domain based on the combination of the matched filter acquisition algorithm and the FFT acquisition algorithm.The acquisition architecture of PMF-FFT acquisition algorithm is designed and the simulation platform of PMF-FFT acquisition algorithm is built under the guidance of theoretical analysis.2.Combining with Matlab simulation results of PMF-FFT acquisition algorithm,the circuit and the system structure are designed on FPGA hardware platform by VHDL language,and the circuit system is discussed in detail.A decoder with binary complement operation instead of multiplier is designed.The experimental results show that the receiver based on the PMF-FFT acquisition algorithm is not only stable,but also has higher speed than the existing Beidou B3 receiver.