Key Technology Research On GNSS With SINS Assisted

With the rapidly improvement of satellite navigation technology,GNSS has already been widely applied in both military and civilian field of navigation and positioning.However,GNSS is always vulnerable to external interference as a means of radiolocation.The vulnerability of GNSS is mainly reflected in:(1)Within the harsh working environments,the availability of useful signal is vulnerability,including signal processing operation under weak signal,signal processing operation under high dynamic and multi-path signal processing under interference environment.(2)There are limitations of information fusion in poor condition,including positioning technology with non-ideal geometry of visible satellites,fault information processing with redundancy,as well as different levels information fusion technology for meeting different requirements of users.Comprehensively comparing space-based,ground-based augmentation system for GNSS,GNSS system with SINS assisted and software radio positioning system,GNSS/SINS integration has been an effective means for application of high accuracy,high dynamic and high sensitivity requirements.In GNSS/SINS integration,the advantage of SINS could be taken,including working without interference of the external environment and high positioning accuracy in a short time,and the inherent defects of GNSS could be avoided.SINS is introduced to aid GNSS for resolving its vulnerability in limited environments.Different integrated architectures and several impact factors including sensitivity of GNSS receiver,capability of anti-interference,positioning accuracy,and capability of fast acquisition are analyzed.The research mainly focus on utilizing GNSS with SINS assisted to solve multi-path problem,autonomous integrity monitoring problem and nonlinear data fusion problem.According to the in-depth analysis of existing multipath mitigation technologies of receiver in signal processing and the principle of narrow correlation technology,cross Teager-Kaiser(TK)energy operator is introduced to realize multipath error estimation in DLL with SINS assisted based on TK operator correlation peak detection.The code delay between reference signal and measurement signal is obtained through cross TK operator consistency checking,and the detection of small chip multipath time delay is realized.Accurate separation of direct signal and multipath signal is realized through the multivariate attenuation of time delay and the energy of the signal.An estimation method using differential adaptive controller is proposed to track multipath time delay.Combined with the cross TK operator,a DLL architecture with multipath delay parameter estimation is designed.The architecture seeks extreme and estimates minimum variance by tracking differentiator controller.Based on the proposed architecture,a new DLL architecture with multipath delay parameter estimation and SINS assisted is designed.Basic theory of fault detection and identify is derived.The performance improvement in integrity control with redundant information of visible satellite is verified.An autonomous integrity control method utilizing innovation residual statistics is proposed and verified in the framework of GNSS receiver with SINS assisted.Virtual visible satellite signal is constructed by using inertial information and satellite ephemeris.HDOP and VDOP are optimized.Fault detection in conditions of no more than four visible satellites and fast time-varying is realized.In view of the defect of new residual error statistical method in slow slope fault detection,a comprehensive integrity control scheme is designed.Rapidly fast time-varying fault detection,effectively slow slope fault detection,and multi-satellites fault detection are achieved by the scheme.Physical principle of distributed and centralized schemes of ultra-tightly integrated navigation system is derived.Non-coherent combination system equations are established.According to analysis of the existing nonlinear filtering algorithm,unscented particle filter(UPF)algorithm is selected,and the flow of UPF in integrated navigation system is established.UPF is applied to the design of combined system.Performance improvement of signal tracking and the effectiveness of ultra-tightly integration are validated.Comparing with EKF and UKF in three-dimensional positioning precision and velocity accuracy,the superiority of UPF is validated.