| Since the end of last century,with the improvement of the number and quality of navigation satellites,aircraft approach and landing(or carrier landing)guidance technology based on global navigation satellite system(GNSS)has attracted much attention,and integrity is one of the difficulties.At present,China has built Bei Dou navigation satellite system(BDS)with excellent performance.Taking the Beidou based precision approach and landing(or carrier landing)guidance as the background,combined with the inertial navigation system(INS),and taking the accuracy and integrity of position increment information as the research object,this thesis studies the tightly coupled BDS/INS integrated navigation,BDS measurement error of dynamic receiver and position increment integrity monitoring.Firstly,aiming at the problem that the measurement update time of multi-system and multi-frequency GNSS/INS integrated navigation equipment with high update rate is too long,a GNSS/INS compact combination method using information filtering is proposed,and the advantages of information filtering in calculation are obtained theoretically.Experiments show that when pseudo-range,Doppler and carrier-phase time difference(TDCP)are used to enhance the effect of tight integrated navigation,the measurement update time after information filtering is greatly reduced,less than 1/10 of that of sequential Kalman filtering.Based on the time reduction,the navigation and positioning accuracy is maintained.Then,according to the requirements of accurate dynamic receiver reference position for accurate modeling of measurement error and cycle slip,the method of obtaining measurement error and cycle slip based on multi-antenna rotating platform is used.On this basis,two methods to improve the success rate of post precise relative positioning by using trajectory constraints are proposed.After processing the long-term(25 days)dynamic data collected by the equipment,the epoch with accurate reference position accounts for 99.944%,which meets the needs of establishing reliable model.Then the measurement error and cycle slip model are statistically analyzed.The main conclusions are as follows: the accidental error of inter satellite pseudo-range measurement error of dynamic antenna follows the normal distribution of 0 mean,the standard deviation decreases with the increase of signal-to-noise ratio(SNR),the standard deviation of pseudo-range error of different orbit types is different,and GEO satellite is slightly worse;The double difference carrier phase between epochs has the characteristics of peak and fat tails,which can be conservatively described by the bi-normal model.The standard deviation of error also decreases with the increase of SNR,but the error standard deviation of satellites in MEO orbit is larger than that of GEO and IGSO;The cycle slip probability also decreases with the increase of SNR.The cycle slip probability of MEO satellite is slightly higher,and the occurrence probability of cycle slips of different sizes is significantly different.It is a kind of peak skew distribution,which can be described by the mixture of Gaussian model.Finally,the integrity monitoring method of location increment is studied,including fault monitoring method and integrity risk analysis.Aiming at the problem that it is difficult to detect multiple faults of GNSS in the initial alignment stage,a cyclic prediction residual method is proposed.Aiming at the stage after the convergence of integrated navigation filter,the missing alarm rate and a posteriori variance in measurement domain of inertial navigation assisted GNSS monitoring are analyzed by using the expected space method.After assigning the accuracy and integrity risk index according to the application background,the integrity risk calculation method of location increment is deduced.In the vehicle and fligt tests,multiple faults are completely detected,and there is no integrity event of error overrun without alarm,which verifies the effectiveness of the proposed method. |
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