Research On Fast Acquisition Techniques Of Beidou B3I Signal In High Dynamic Scene

Beidou system can provide global satellite position,velocity and time(PVT)service and has broad application prospects in both military and civilian fields.Beidou B3 I signal is a global open service signal that broadcasts on all Beidou satellites.Satellite navigation receivers in the military field work in high dynamic scene,which are installed on high-speed vehicles such as aircraft,missiles and rockets.Fast signal acquisition technique is one of the key techniques in baseband signal processing of high-dynamic receivers and is a determinant of the dynamic range of receivers.Therefore,the research on fast acquisition techniques of Beidou B3 I signal in high dynamic scene has important value in practice.Based on an overview of the research status of satellite navigation signal acquisition technologies at home and abroad and considering characteristics of high dynamic Beidou B3 I signal,the fast acquisition algorithm of Beidou B3 I signal in high dynamic scene is designed and implemented.The main contributions are listed as follows:1.Architecture of satellite navigation receivers and the theory of direct sequence spread spectrum(DSSS)signal acquisition are illustrated,various satellite navigation signal acquisition algorithms are studied,and the acquisition ability of acquisition algorithms of Beidou B3 I signal is verified by simulation;2.According to the characteristics of high dynamic Beidou B3 I signal,the fast acquisition algorithm of high dynamic Beidou B3 I signal is proposed,and the algorithm architecture of master search unit and slave search unit is designed.The master search unit adopt large step in frequency domain to acquire precise code-phase and coarse doppler frequency,using two sub-correlators;slave search unit acquires fine estimation of doppler frequency under the condition that the code-phase is known,and uses zero padding to compensate scalloping loss Theoretical analysis shows that compared with PCS algorithm,the computation of the proposed algorithm is reduced by about 20%,and the acquisition time of the proposed algorithm is shorter than PCS algorithm and PMF-FFT algorithm.The detection probability and frequency response of the proposed algorithm are obtained by Monte Carlo simulation.The sensitivity of the proposed algorithm is-134 d Bm and the dynamic range is-20 k Hz to 20 k Hz;3.On the hardware platform of satellite navigation receiver based on ZYNQ chip,the ranging code generation module,carrier NCO module,main correlator module,partial matched filter module and detection and control module of high dynamic Beidou B3 I signal fast acquisition algorithm are designed.Based on Vivado development environment and using C language and VHDL language,the fast acquisition algorithm of Beidou B3 I signal in high dynamic scene is implemented;4.The test environment of the fast acquisition algorithm of Beidou B3 I signal is built,and tests for the proposed algorithm were carried out by using high dynamic signal simulator.The test content includes the basic function of acquisition,acquisition time and acquisition dynamic range.The test results show that the proposed acquisition algorithm can meet the design requirements.