Research On The Key Technology Of Receiving And Processing The BDS B1C Signal Under Highly Dynamic Environment

The Beidou Global Positioning System(BDS)attracts worldwide attention,it will be fully serviced in 2020 and surely set off the climax of the related research and application.BDS adopts B1C modulation signal with independent intellectual property rights in B1 frequency band.The overall technology of the signal is advanced,the component structure is complex and the pseudo-code ranging accuracy is higher compared with B1I signal,meanwhile it is compatible with interoperability,good resistance to multipath performance.Many different optimized receiving schemes can be proposed for B1C signals.The thesis studies the key technologies of B1C signal at the beginning of the full use of B1C signals,including QMBOC signal reception processing under high dynamic conditions for some special application environments,such as precision guided weapons,satellite maneuvering,and adjacent space vehicles.It meets the needs of different users of missile and space platforms as well as has important research significance and application value.The reception of QMBOC signals under high dynamic conditions is bound to pose challenges in fast and stable acquisition,high dynamic carrier tracking and high reliability and high precision pseudo code tracking.The thesis is to carry out research work in five parts:signal characteristics,acquisition methods,carrier tracking,code tracking and GNSS L1 signal interoperability receiving model.The paper mainly completes in the following work:1.The structure,composition and power allocation of B1C signal are analyzed in detail,while the correlation function and power spectral density between B1C signal and its components are derived and simulated.The comparison and simulation analysis of the BOC(1,1)component of the pilot component for the non-matching reception and matching reception of the QMBOC signal,then the optimal interval of correlation of BOC(1,1)non-matching synchronous reception is 0.2 chips,showing that the mismatched receiving code tracking error better than the matched method at this interval,however with an Gabor bandwidth loss of 0.2MHz and a loss of output signal-to-noise ratio is nearly 1.6dB.The method of non-matching reception has the characteristics of simple local pseudo-code structure and is easy to implement a fast algorithm,and can be used for the acquisition of QMBOC signals under high dynamic conditions.2.The BPSK-Like combined with the PMF-FFT method(matching reception)of the QMBOC signal and the BOC(1,1)non-matching acquisition method are compared and analyzed.The simulation shows that the average peak-to-average ratio of the latter was higher than the former by more than 5dB and sensitivity performance is superior.For broadband receiving users,according to the characteristics of constant envelope multiplexing and multi-path time synchronization of B1 frequency point signal,under the background of the demand of high dynamic fast acquisition,a fast acquisition algorithm of B1C signal assisted by B1I with PMF-FFT operation is proposed,B1C signal acquisition can be achieved faster under high dynamics.3.A Kalman filter-based FLL+PLL carrier tracking method(KFFPLL)is proposed under high dynamic conditions.This method can complete the tracking of the general JPL high dynamic verification model.The mean value of KFFPLL phase estimation error is smaller than the FLL+PLL method 0.0286rad,the error mean square error is 0.48rad~2 less than the FLL+PLL method.Based on the idea of adaptive Kalman filter,an extended Kalman filter high dynamic carrier tracking method with FLL dynamic monitoring jerk is proposed to solve the problem of easy-lock-loss under high dynamic scene.4.The BOC(1,1)dual-loop tracking and ASPeCT method of QMBOC signal are analyzed.The results show that the ASPeCT method has tracking ambiguous residuals.The correlation interval of dual-loop tracking subcarrier satisfies the odd multiple of0.3 chips to obtain the maximum linear phase discrimination interval.The advantage of BOC(6,1)tracking accuracy is not obvious.The BOC(1,1)has better tracking accuracy for QMBOC signal by non-matching tracking.Based on the comprehensive analysis,a four-loop tracking method using carrier loop,code loop and BOC(1,1)subcarrier loop and BOC(6,1)subcarrier loop is proposed.The simulation results show that when the SNR is greater than-28dB,the tracking error tends to zero(less than 0.03 chips).5.B1C signal,GPS L1C and Galileo E1 signal have the same frequency and similar signal form.On the basis of reception of B1C signal,a modular and configurable universal MBOC signal receiving model is proposed to meet the GNSS interoperability requirements.The model includes a standardized tracking model,a related accumulator model,a PMF-FFT model,a software modular configuration model and so on,moreover the feasibility of the scheme is verified in actual engineering projects.After a lot of derivation and simulation work,the thesis makes innovative research in the following aspects:(1)According to the characteristics of B1 constant envelope multiplexing and multi-path time synchronization,it is proposed to use B1I with PMF-FFT operation to assist B1C signal acquisition;(2)Four-loop tracking method is proposed,including carrier loop,code loop and BOC(1,1)subcarrier loop and BOC(6,1)subcarrier loop for QMBOC signal tracking;(3)It is proposed a method based on extended Kalman filter with FLL dynamic monitoring jerk under high dynamic carrier tracking method,solving the problem of easy-lock-loss in high dynamic scene.