Research On Influence Of GNSS Signal Distortion On Precision Point Positioning

The non-ideal property of GNSS load will lead to signal distortion,and then deviate the distance measurement observation.These biases are related to both signal distortion characteristics and receiver parameter settings,and cannot be eliminated by the unified correction provided by the system.With the wide application of GNSS in the world and the improvement of its strategic position,users' demands for accuracy and reliability gradually increase.Precise point positioning is an important high-precision positioning method.The positioning accuracy can reach cm level.The distortion caused by signal distortion cannot be ignored.This paper analyzes the influence of GNSS signal distortion on PPP,and It has important guiding significance for the future GNSS system construction with higher accuracy and reliability.First,the influence of GNSS signal distortion on distance observation is analyzed by simulation,mainly based on filter and high power amplifier(HPA).The situation of memoryless HPA and memory HPA under different signal bandwidth is studied.Then,the effect of pseudorange biases on the PPP based on ambiguity resolution(PPP-AR)is studied through theories,and it is divided into two cases,based on FCBs and integer clock.Finally,analysis the influence of pseudorange biases on PPP based on real-valued solution by using actual observed data.This paper makes the following conclusions:(1)The non-ideal property of filter and HPA both will cause signal distortion,but the influence of HPA is far less than filter.(2)The linear distortion of the filter mainly results in the pseudorange biases,which has little effect on the carrier phase measurement.(3)The pseudorange biases is not only related to the filter characteristics,but also related to the front-end bandwidth and correlator design of receiver.(4)The pseudorange biases will worsen PPP-AR and lead to error of the FCBs providing by a network of stations,thus the ambiguity of user station cannot return to a integer.The success rate of PPP-AR will decline.(5)The performance of PPP-AR without considering pseudorange biases effect is similar to the algorithms based on real-valued solution.(6)The pseudorange biases will prolong the convergence time and increase the positioning error of the PPP based on real-valued solution,especially in horizontal.