Research And Realization On Theories And Methods Of Precise Positioning Base On BeiDou Navigation Satellite System

BeiDou Satellite Navigation System is the global satellite navigation system developed byChina independently. It follows the development roadmap of starting with regional services firstand expanding to global services later. A three-step development strategy has been taken. TheBeiDou Navigation Satellite System is officially announced in operation and the Signal inSpace Interface Control Document-Open Service Signal B1I (Version1.0) is released on thenews conference held at the Briefing Hall of the State Council Information Office on December27,2012. As the national strategic emerging industries, the BeiDou satellite navigation systemplays an important role in the protection of national economic and social security, the promotionof the national informatization construction, the transformation of the mode of economicdevelopment and the promotion of the construction of modernization of national defense and soon various aspects. The construction of the regional system of satellite navigation industry of ourcountry is facing a blowout phase. Abroad satellite navigation industry are in scale developmentnow, and the market is mainly monopolized by GPS, so the priority of BeiDou satellitenavigation application is enhancing user confidence and transforming system requirements tomarket and industrial strength. Static and relative dynamic positioning technology based oncarrier phase observation is the main mode of BeiDou application in future, is the preconditionof building and maintaining time and space benchmark, is one of the most important applicationsin basic research, such as precision of surveying and mapping, atmospheric sciences and earthsciences, etc, and is the main way of gathered BeiDou high precision applications. BeiDouRegional Satellite Navigation System is the first heterogeneous constellation(5GEO+5IGSO+4MEO) satellite navigation system in the world. Because of the BeiDouregional system differences with GPS, such as the distribution of the constellation and thecontent of the signal, orbit precision, observation data quality, etc. Research on realizing highprecision static and dynamic relative positioning, and demonstration on its feasibility andprecision plays an important role in enhancing the system application prospect. This papersystematically studied the theory and method of the BeiDou precise relative positioning andmade breakthroughs in the key technologies BeiDou high-precision measurement, such as thedata quality analysis, the data pre-processing, the solution of ambiguity, parameters estimatingand so on. The BeiDou high-precision static and dynamic relative dynamic positioning dataprocessing method was proposed; the validation of the BeiDou geodetic control networkpractice and its precision is researched. The BeiDou dynamic relative dynamic positioning, RTKand BeiDou compatible with GPS positioning have been implemented. The correctness of thetheory and method involved above is verified, and the avalibility and indicator of the application of Beidou in high-precise measurement is validated. At the same time, this paper activelydeveloped BeiDou application practice research and solved the aerospace measurement andcontrol equipment dynamic performance test and accuracy evaluation problem based on BeiDouhigh precision positioning technology. In this dissertation, the main work and innovation pointsare summarized as follows:1. The BeiDou relative positioning observation model, error model and stochastic model aregiven based on the characteristics of BeiDou observation data. In consideration of thesignificance of the linear combinations of original observations in the data preprocessing,calculating ambiguity, ionospheric delay correction and so on, the characteristics of thewide-lane linear combination, ionosphere-free linear combination, the ionosphere residualcombination and MW linear combination are analyzed in detail. Referring to the method ofeliminating error correction in GPS data processing, the definition, characteristics and thecommonly used method of correction of the satellite orbit error, satellite clock error, ionosphericdelay, tropospheric delay, multipath effect and observation noise are given.2. The accuracy of the BeiDou pseudorange and carrier phase observation is analysizedquantificationally. The method to analyze the pseudorange measurement noise and multipatheffect by using the combination of the pseudorange and carrier phase is proposed. The systematicanalysis of the BeiDou satellite (GEO/IGSO/MEO) multipath effect is made; A comprehensiveunderstanding of the current BeiDou relative positioning data quality is obtained by Beidouzero-baseline experiments on the carrier phase noise measurement and BeiDou the precision ofbroadcast ephemeris assessment based on the precise orbit determination. A BeiDou datapreprocessing scheme is proposed. The ionosphere-free combination is used to detect grosserror, The MW combination and the ionosphere residual combination is utilized to detectcycle-slip, and geometric-free combination is used to repair the cycle-slip. The effectiveness ofthe proposed scheme is validated with the measured data.3. Through the comparison and comprehensive analysis of the existing ambiguity fixedmethod of GNSS in application of BeiDou, the method of quasi ionosphere ambiguityfixed,whose performance is reliable,is selected, and applied to BeiDou geodetic control networkdata processing. The suitability of the LAMBDA method for resolving the Beidou ambiguity isstudied, and the validity of fixing the ambiguity in fewer epochs by using the LAMBDA methodis researched based on the ambiguity of covariance matrix of decorrelating processing. Thisprovides the basis for fast ambiguity fixing in the BeiDou relative dynamic measurement.4. The BeiDou relative positioning theory and method by using the un-differenced data isproposed, and the ambiguity fixed method by using un-difference data is described in detail, andthe consistency of this method with the traditional relative positioning based on the double difference data is proved. Comparing to the double difference data, the un-differenced data areindependent of each other, containing more information (e.g., clock error). Besides, the dataprocessing is more flexible and convenient. Based on two BeiDou baselines, the single baselinestatic relative positioning, relative dynamic positioning and dynamic for dynamic relativepositioning were conducted. The results show that the static relative positioning accuracy canreach the mm level, the dynanic relative positioning and dynamic for dynamic positioningaccuracy is superior to2cm in horizontal direction and4cm in elevation direction.5. Based on the accuracy and feasibility problem that the BeiDou high precision user isurgently care for, the BeiDou geodetic control network practice and precision validation study isperformed. The long, medium and short baseline BeiDou geodetic control network using BeiDouexperiment assessment system and BeiDou experiment network dual-model receiver is built.The processing method of the BeiDou control network is systematically studied; and the dataquality control strategy based on the various carrier phase combination observations and theinternal and external accuracy validation scheme is designed, and the millimeter level relativepositioning is realized. Through the indexes of the station coordinates and the repeat precision ofthe baseline, the rate of the ambiguity fixed, positioning residual and so on, A comprehensivecomparative study is compared with that of GPS. The feasibility that implementing thegeodetic control network by BeiDou and the accuracy can be reached is demonstrated.6. The relative dynamic positioning based on BeiDou is thoroughly researched. Theparameter estimation method of BeiDou dynamic relative positioning based on the forwardKalman filter and combination Kalman filter is implemented. The solution mathod of theestimated parameter vector dimension change owing to the increase or decrease of ambiguityparameters along with satellite up and down is studied; and the BeiDou relative dynamicpositioning software is developed. The cm-level accuracy BeiDou relative dynamic positioningis realized by using real data. The influence of factors such as the baseline length and parameterestimating method on the positioning accuracy is researched. The results show that the accuracyof the BeiDou relative dynamic positioning can reach the cm-level. But for the availability, as aresult of BeiDou receiver signal failure occurs frequently, satellite observation geometry is toreduce and convergence accuracy of the satellites to capture are poorer, so the point positioningresults have a large number of outliers and the availability is relatively low.7. In order to improve the availability of dynamic positioning when the BeiDou observationgeometry is not ideal, the key technology such as the difference coordinate and time benchmarkin Beidou/GPS combined positioning is reaserched. The time difference eliminating method bythe independent conbination difference in system is proposed. It simplified the operation stepsand overcomed current compatible positioning difficulty without the time difference between BeiDou and GPS. The results show that the accuracy of BeiDou compatible with GPSpositioning is superior to BeiDou, and the superiority mainly owes to the availabilityimprovement, which is about20.6%.8. The implementation method of BeiDou RTK is discussed. Firstly the RTCM2.3cabletype is introduced in detail, and the characteristics of differential positioning by using cable18/19(pseudorange/carrier phase observation value) and the message20/21(pseudorange/carrierphase correction value) is thoroughly analyzed. On the basis of that, the BeiDou RTK differentialcables supporting the RTCM formats is predefined; Static and dynamic baseline experimentswere used respectively for BeiDou RTK, and the positioning result was analyzed.9. The theory and method research of the measurement and control device accuracyidentification based on the BeiDou relative dynamic positioning is performed. Based on theaccuracy index, the BeiDou accuracy identification system is built. The accuracy identificationdata processing method is studied. The radar accuracy identification experiment is performedbased on that system. This played an important role in understanding the equipment, trackingperformance and accuracy of measurement, and finding and analyzing the equipment problem asearly as possible.