Design Of Low-power Space-borne BDS Receiver And Its Application In Real-time Orbit Determination

Bei Dou Navigation System is a global navigation system,which is independently developed by China.As of December 2019,the number of Bei Dou-3 satellites has reached 28.It is expected to have global high-precision positioning navigation service capability in 2020.Compared with other navigation systems,Bei Dou system has a multi-frequency signal structure,contains GEO,IGSO and MEO multi orbit constellation,and uses hydrogen atom clocks with better long term stability.It will gradually become a hotspot in the field of space-borne receiver research.Under the historical opportunity of the completion of the Bei Dou Global Navigation System,developing low power and high precision Bei Dou navigation receivers is of vital importance for space missions.The main contents and contributions of this thesis include:(1)This thesis aims to solve the problems of Zhejiang University's self developed GNSS navigation receiver carried in the ZDPS-2 mission.We designed and implemented the signal acquistion,tracking and other functions of the Bei Dou receiver with B1 I,B3I frequencies.(2)Due to the low power consumption and high resource requirements of the space-borne receiver,a Xilinx Kintex 7 series FPGA chip is used to reduce the power consumption of the receiver and increase the number of tracking channels.While receiving the self-location results,the receiver achieves high-precision measurements of the original observations such as pseudorange and carrier phase.The performance of the receiver was evaluated through simulators and outdoor tests.(3)Hardware-in-the-loop simulations of the low orbit satellite scene were conducted with navigation signal simulators.The real-time orbit determination performance of low orbit satellites under the BDS-3 scene was evaluated.The pseudo code rate of the B3 I signal is 10.23 Mcps,which is significantly higher than the B1 I signal and GPS civilian navigation signals.The results show that the accuracy of the B1/B3 dual-frequency pseudorange combination is comparable to that of GPS orbit determination under the same conditions.In GRAPHIC combination,the orbit determination accuracy of the B3 I signal is significantly better than that of the B1 I signal,and is comparable to the orbit determination results of L1 C /A and L2 C.The low power GNSS receiver designed and implemented in this thesis is compatible with GPS(L1 C/A,L2C)and Bei Dou(B1I,B3I)navigation signals.The actual test shows that the acquisition sensitivity is-131 dBm,the tracking sensitivity is-133 dBm,and the power consumption is 6.88 W.The three-axis position accuracy using the B1 I and B3 I dual-frequency pseudo-code combination reaches 4.60 m,5.66 m,and 5.59 m.The GRAPHIC combination of the B1 I signal reaches 2.15 m and 1.80 m,2.46 m,and the B3 I signal reaches 1.31 m,1.12 m,and 1.85 m,which can meet the application requirements of micro satellite's real time orbit determination.