Research And Implementation Of RTK-GNSS Software IF Simulator

With the rapid development of GNSS systems,Real Time Kinematic(RTK)has been able to provide real-time centimeter-level positioning accuracy in the work area,and has been used in autonomous driving,drones,precision agriculture and industrial robots.A wide range of applications.The satellite navigation signal simulator is the core equipment for the development and testing of the receiver.It can provide a reproducible and controllable simulation environment for the development and testing of the receiver in an indoor environment,which can reduce the number of initial field tests and shorten the algorithm.Verification cycle.At present,there is less research and implementation on software IF signal simulator with RTK positioning function.To this end,this paper implements the RTK-GNSS software IF signal simulator of the whole system full-frequency point,and based on the software IF signal simulator,the loop tracking accuracy is theoretically perfected and quantitatively analyzed,and the multi-system multi-frequency point is single.Point positioning and RTK positioning performance were tested.The main contributions and innovations of this paper include:(1)The typical code tracking error model is analyzed in detail.It is found that the deviation between the theoretical value and the actual value of the code tracking error model is large under partial loop parameters.A coherent code tracking error model based on discrete time signal is proposed.Based on the accuracy evaluation of the software simulator,the error model proposed in this paper greatly improves the accuracy of the code tracking error.(2)An integer-degree ambiguity reliability model based on pseudo-carrier phase difference is proposed,and the accuracy of the model is verified based on the software simulator.At the same time,the cause of the carrier phase ambiguity is analyzed in detail.It is proved that the basic unit of the local initial time of the receiver directly affects the integer characteristics of the ambiguity,and the basic initial time of the receiver at each frequency is given.Value unit(3)The implementation of the full-system full-frequency RTK-GNSS software simulator was carried out,and the implementation architecture of the software simulator was elaborated.At the same time,a software receiver test platform was built to verify and analyze the single-point positioning performance and RTK positioning performance of the IF signal.