Research On Zero Value Measurement And Integrity Monitoring Of High Precision Receiver

With the development of satellite navigation technology,satellite navigation system is becoming more and more demanding on precision.The user receiver channel non-ideal characteristics will affect the positioning accuracy of ordinary users,and the monitoring receiver channel non-ideal characteristics will affect the accuracy of the entire system.The affection above is partly reflect on the impact on the zero value,thus it is very important to study the influence of the non-ideal characteristics of the channel on the zero value measurement.Besides,the positioning accuracy of the centimeter level can be obtained by using the carrier phase.However,the carrier phase has the problem of ambiguity fixed and cycle slip compared with the pseudorange,and the detection of ambiguity fixation error and cycle slip can be realized by means of integrity monitoring.In this paper,based on the above background,the main research contents include the following parts:In the first part,the superposition relation between the zero value of the cascade channel and the zero value of each subchannel is not clear.The superposition characteristic of the zero value of the cascade channel is analyzed when the different group delay channel is cascaded,And the software receiver is used for simulation verification.The results show that when the zero order group delay channel is cascaded with other channels,the zero value satisfies the superposition characteristic.The zero value of the odd-order group delay channel is zero,so the odd value of the odd-order group delay channel is satisfied when the zero value satisfies the superposition characteristic.In the case of the first order group delay channel and the second order group delay channel,the second order group delay channel,the quadratic polynomial group delay channel is cascaded with each other,the zero value does not satisfy the superposition characteristic.At this time,the group delay coefficient constraints can be used to satisfy the superposition characteristics.The second part aims at the difference of the zero value existing between a variety of tracking methods for the BOC signal when the channel is not ideal.Firstly,the basic principle of BOC signal modulation and four tracking methods is introduced,and the analysis model of zero value is established.The influence of different tracking modes on zero value under nonunion of phase-frequency characteristics and non-ideal amplitude-frequency characteristics is analyzed and compared.The results show that the maximum difference between the zero value of the receiving mode is 8ns for a particular scene with non-ideal frequency.When the phase frequency characteristics are ideal and the amplitude-frequency characteristic is not ideal,the zero value is not influenced.When the phase frequency characteristic is not ideal,the non-ideal amplitude-frequency characteristic will increase or decrease the influence of the phase frequency characteristic on the zero value,which is relative with both the specific phase frequency characteristic and amplitude-frequency characteristic.In the third part,the method of integrity monitoring algorithm for detecting ambiguity fixed error and cycle jump is studied.In this paper,the mechanism of the wrong ambiguity fixation is analyzed,and its influence mechanism is studied.It is pointed out that it is difficult to distinguish the correctness of the ambiguity from the integrity of the current epoch,while in the fixed and hold mode,the changes of satellite geometry can be used to detect wrong fixation of ambiguity.Besides,based on the coherence between carrier phases in the same epoch,the CRAIM technique is used to detect the carrier phase cycle slip,and a method of searching and repairing the cycle slip based on the size of the statistics is proposed.