MIMU/CSAC/BDS/GPS Integrated Navigation Micro System Technology Research

Positioning,Navigation and Timing(PNT)is an important technique for expressing spatial information and time information.At present,PNT users are increasing,especially in the fields of UAV,autonomous driving,communications and so on.The technology of PNT not only promotes the national economy,but also plays a decisive role in the construction of national security and military fields.It is the embodiment of China’s comprehensive national strength and international standing.In order to solve the vulnerability of the Global Navigation Satellite System(GNSS)and enhance the service performance of PNT,the use of inertial measurement devices,high-precision clocks as the core device and integrate with GNSS has become the main route for the development of the technology of PNT.Under the background of the technological development of MEMS Inertial Measurement Unit(MIMU)and Chip Scale Atomic Clock(CSAC),the technology of Micro-PNT has developed rapidly and has become a new idea for the development of the technology of PNT.At present,there is no mature of positioning navigation and timing micro system installed high-precision clock as time-based system in the market.Therefore it is more meaningful to develop the prototype of positioning navigation and timing micro system.This paper uses MIMU,CSAC and BDS/GPS dual-constellation navigation receiver for fusion.And this scheme is a reasonable choice.Combining with the development trend of Micro-PNT,this paper designs MIMU/CSAC/BDS/GPS integrated navigation micro system.The main contents are as follows:(1)Introduction of MIMU/CSAC/BDS/GPS integrated navigation micro system.It mainly introduces inertial navigation system,chip atomic clock,BDS/GPS satellite navigation system,and the development status of positioning navigation and timing micro system in domestic and overseas.(2)Combined with MIMU/CSAC/BDS/GPS integrated navigation micro system performance requirements and technical theory analysis,this paper gives the software design and hardware design of the system.(3)MIMU/CSAC/BDS/GPS integrated navigation micro system hardware design: including the selection of the core components of the system,the design of the interface between the system modules and schematic diagram,the implementation of PCB and the installation of the system,and the design of the DSP driver.(4)In this paper,the integrated positioning of BDS/GPS dual-constellation is studied,and the carrier phase smoothing pseudorange algorithm for ionospheric delay compensation is designed.In addition,the influence of receiver clock error on positioning accuracy is also analyzed,and CSAC is used to assist BDS/GPS receiver in positioning calculation.In the high dynamic and weak signal environment,the satellite signal is easy to lose lock.The disadvantages of pure receiver relocation are analyzed.A relocation algorithm using MIMU/CSAC to assist BDS/GPS receiver is designed,which can shorten the relocation time of the system.(5)From the practical engineering application,the core modules of MIMU/CSAC/BDS/GPS integrated navigation micro system are tested.The performance and accuracy of the principled sample machine are verified by the field test and flight test.