Research On Evaluation Methods Of Satellite Navigation System Performance

With the development of global satellite navigation system,for example,GPS and so on,some regional navigation systems and augmentation systems are developing rapidly.The continuous development of satellite navigation system has attracted the users' attention to satellite navigation performance,which makes the navigation system performance become the key of satellite navigation system competition in the field of GNSS application.The SIS performances of GPS and BDS are evaluated in this paper.Aiming at the shortcomings of the current accuracy evaluation model,such as the large computation cost and the limited evaluation conditions,the segmented SIS user range error(URE)evaluation model and the SIS user range rate error(URRE),user range acceleration error(URAE)evaluation model based on Allan variance are proposed firstly.Then the SIS accuracy of GPS and BDS are evaluated by using the broadcast ephemeris and precise ephemeris.On this basis,the normal distribution feature of GPS SIS URE is fitted by using the Q-Q figure,which verified the premise of GPS SIS integrity evaluation.And then the GPS SIS URE integrity is evaluated based on the measured results of the stantaneous SIS URE accuracy.Furthermore,the SIS continuity evaluation model based on the reliability is established,and the mean time between failures(MTBF)is used to characterize the probability that there is no continuity loss in unit time.Aiming at the incompleteness of the current availability model,a per-satellite availability evaluation model based on Markov process is established.Moreover,the constellation availability evaluation model are proposed by combining the satellite failure rate,repair rate and backup situation.By analyzing the measured data,the probability of the continuity and availability of GPS and BDS are calculated respectively.Based on the measured data and the proposed evaluation model,this paper evaluates the accuracy,integrity,continuity and availability of GPS and BDS,respectively.The evaluating results verify the validity of the evaluation models proposed in this paper and the conformity between the performance of the two systems and their own performance indicators.Moreover,the research on evaluation methods of satellite navigation system performance in this paper has a great significance to the globalization and the following development of the BDS.