Research On Baseband Signal Processing Algorithm Of Base Station Receiver Of Ground-based Radio Navigation

The terrestrial wireless navigation base station receiver system belongs to a new quasi satellite navigation system,and has the advantage of high positioning accuracy,high flexibility and extensibility compared with traditional GNSS navigation receivers,and is widely applied to systems such as topography and mine exploration.The important research direction of tunnel positioning,urban navigation,military union navigation,and the development of national positioning infrastructure is now focused on the development of the signal transceiver system and the realization of traditional receiver performance.Among them,the system baseband signal processing algorithm is mainly based on theoretical research and modeling,and hardware circuits lacking the aboveground navigation reception system perform tests and tests in combination with the acquisition and tracking algorithm in baseband signal processing.It combines the hardware circuit of the ground wireless navigation base station with the FPGA device development platform,and performs the algorithm verification and the joint test.The main work and contributions of this thesis are as follows:1.This thesis analyzes the limitations of the traditional satellite radio navigation receiver system,analyzes the current development of the ground radio navigation system receiver,and studies in detail the carrier acquisition and pseudo code tracking technology mainly used in the ground radio navigation station receiver system.2.The thesis studies the working principle of baseband signal processing algorithms such as carrier receiver of ground radio navigation base station and PN code acquisition and tracking,and obtains the mathematical model developed and implemented by parallel acquisition and tracking algorithms of multiple base stations.We also studied and analyzed the characteristics of the algorithm,such as capture time and tracking accuracy.3.The thesis has developed a signal acquisition algorithm based on frequency band parallel code phase and a signal tracking algorithm based on Cordic,completing baseband signal processing components such as data preprocessing,skip reception,correlation calculation,tracking loop recognition,and filtering.For example,Verilog&IP design and FPGA download testing.4.The hardware platform of the base station radio navigation receiver was established,the carrier acquisition and pseudo code tracking algorithms were loaded and verified,the performance indicators of the design algorithm were analyzed,the synchronization test of baseband signal processing algorithm was completed,and the acquisition and tracking were conducted in the transmission and reception systems,When the maximum frequency difference between the local frequency and the received data frequency is 10 KHz,the system can measure and track the navigation message sent by the base station while capturing it.The carrier frequency of the transmitted signal can be locked at 100 ms,and the pseudo code frequency can be locked at 60 ms,ultimately enabling successful detection of the reception of the signal sent by the base station.