基于平方根信息滤波的GNSS导航卫星实时精密定轨理论与方法

发布时间：2018-05-18 12:12

本文选题：多系统实时精密定轨 + 平方根信息滤波　；参考：《武汉大学》2016年博士论文

【摘要】：GNSS技术发展至今,一直致力于为用户提供实时、高精度、高可靠性的导航定位授时服务。GNSS高精度实时定位服务系统作为导航定位系统的有力支撑,通过提供高精度的实时轨道、钟差、电离层产品等信息,使得任何时间全球任何地点的用户可以实现高精度的定位。随着实时产品质量和可靠性的逐步提高,基于全球或区域跟踪网的实时精密定位服务将广泛应用于低轨卫星精密定轨、空间气象监测、地震监测与海啸预警、地球板块运动与动力学研究等多个领域,是目前GNSS应用技术研究的热点之一。稳定可靠的高精度轨道是实现卫星导航高精度定位服务的前提条件。导航定位中卫星位置作为动态基准,其轨道精度将直接影响到用户的定位精度。随着广域范围内实现实时精密厘米级服务的PPP-RTK技术的提出,对卫星轨道位置的实时性和精度提出了更高的要求。由于严重依赖于动力学模型的精度,目前常用的基于轨道预报获得实时轨道的方法存在不足与限制,尤其对于我国目前的区域北斗卫星导航系统,存在轨道力模型精度不高、不同姿态模式切换、轨道机动等因素,预报轨道的精度和可靠性难以保证,迫切需要发展新的实时定轨理论方法、算法模型与软件系统,以提升北斗系统的高精度实时定位服务能力。本文围绕GNSS实时高精度轨道滤波处理中的关键问题展开系统深入的研究。重点解决北斗卫星姿态控制模型建立、地影期间实时轨道确定、轨道机动处理等难点问题,在此基础上提出了采用自适应平方根信息滤波的实时轨道确定方法与策略,研制了基于滤波解算的多系统导航卫星实时精密定轨软件系统,通过实测数据验证了滤波定轨算法模型的正确性以及软件产品的性能。论文的主要研究工作和贡献如下：1)从卫星运动学模型、观测模型和参数估计三个方面,系统研究了导航卫星实时精密定轨的理论方法,主要包括卫星运动方程离散化及摄动力模型、观测误差改正及线性化、批处理解算采用的最小二乘估计方法和实时解算采用的平方根信息滤波方法。对本文实时定轨中采用的平方根信息滤波算法进行了重点研究,给出滤波解算定轨处理流程后,推导了滤波定轨中非线性误差和过程噪声随机函数模型。2)归纳分析了当前各导航卫星的偏航姿态模型以及用于姿态角估计的反向PPP算法,深入研究了北斗IGSO和MEO卫星偏航姿态切换机制。针对北斗IGSO和MEO卫星动偏零偏姿态切换期间初始姿态模型偏差会严重影响精密定轨参数估值,使得反向PPP估计的姿态角偏离实际值的问题,提出了一种改进的反向动态PPP估计方法,成功估计出了北斗IGSO和MEO卫星姿态模式切换期间姿态角的变化。基于估计的卫星姿态角,建立了北斗IGSO和MEO卫星的偏航姿态经验模型,并通过精密定轨结果验证分析了模型的准确性。并在本文北斗卫星实时精密定轨的研究中,均采用该偏航姿态模型对各相关误差项进行改正。3)研究了实时精密定轨观测模型精化与质量控制方法,实现了多系统实时定轨滤波处理中模糊糊度参数的固定。通过实测数据进行验证分析,结果表明：相比于浮点解,模糊度固定后GPS和北斗卫星三维轨道精度平均提高了2cm左右。4)针对机动卫星实时精密定轨的难题,深入研究了卫星机动的实时探测、机动期间卫星精密轨道的确定以及机动后精密轨道的快速恢复等关键问题。提出基于预测残差对卫星机动进行实时探测,探测到卫星机动后,采用自适应平方根信息滤波的方法确定机动期间卫星的实时轨道。通过北斗C05和C08卫星机动期间的实测数据对该方法的有效性进行了验证,结果表明：该方法可以有效探测出卫星机动,能有效避免因轨道机动造成的滤波发散,机动期间卫星对应测站的最大残差在0.3m以内,由于自适应滤波可以保持解算参数的连续性,大大缩短了机动后精密轨道恢复时间,机动结束后的3-6h定轨精度即可恢复至机动前的正常水平。5)分析验证了实时精密定轨滤波算法对GPS卫星地影期间的适用性。结果表明：地影卫星的实时滤波轨道显著优于IGU超快速产品的实时轨道,在滤波解算时增大地影期间轨道参数的过程噪声可进一步提高GPS BLOCK IIA地影卫星的三维轨道精度。6)基于武汉大学导航数据综合处理软件(PANDA)平台,开发了基于平方根信息滤波的多系统导航卫星实时精密定轨系统。通过一个月实测数据对本文提出的方法与研制的软件系统进行了验证分析,结果表明：GPS和GLONASS实时轨道与IGS事后精密轨道相比,三维精度分别为6.7cm和9.3cm.北斗IGSO和MEO卫星SLR检核残差平均偏差在10cm以内；GEO卫星SLR检核平均偏差为20.7cm,相比于事后轨道,与SLR的系统性偏差减小了20cm左右。通过采用实时滤波轨道和预报轨道两种方案对实时卫星钟差估计,证实了滤波轨道可以有效避免因为预报轨道不连续引起的钟差跳变问题。最后基于动态精密单点定位算例对软件解算的实时产品进行了验证,定位结果表明：相比于基于预报轨道的实时产品,采用本文滤波定轨软件解算的实时产品可以显著提高北斗单系统的动态定位精度,多系统精密定位用户可以实现水平3cm,高程5cm的定位精度。
[Abstract]:GNSS technology has been developing to provide users with real-time, high precision, high reliability navigation and positioning service.GNSS high precision real-time positioning service system as a powerful support for navigation and positioning system, by providing high precision real-time orbit, clock difference, ionospheric products and other information, any time in any place of the world to use With the gradual improvement of real-time product quality and reliability, real-time precision positioning service based on global or regional tracking network will be widely used in many fields, such as low orbit satellite precision orbit determination, spatial meteorological monitoring, earthquake monitoring and tsunami early warning, earth plate motion and dynamics research, and so on, is GNSS One of the hotspots in the research of application technology. Stable and reliable high precision orbit is the prerequisite for high precision positioning service for satellite navigation. The orbit accuracy of the satellite position in the navigation and positioning will directly affect the positioning accuracy of the user. With the implementation of the PPP-RTK technology in the wide area real reality, the precision centimeter level service is proposed. There is a higher requirement for the real-time and precision of the satellite orbit position. Because of the serious dependence on the accuracy of the dynamic model, the current methods of obtaining the real-time orbit based on the orbit prediction are insufficient and limited. Especially for the current regional Beidou satellite navigation system, the accuracy of the orbit force model is not high and different. Such factors as attitude mode switching and orbit maneuver are difficult to ensure the accuracy and reliability of the forecast orbit. It is urgent to develop a new theory and method of real-time orbit determination, algorithm model and software system to improve the high precision real-time positioning service ability of the Beidou system. This paper focuses on the key problems in the GNSS real-time high precision track filtering process. In order to solve some difficult problems, such as the establishment of the attitude control model of the Beidou satellite, the real time orbit determination and the trajectory maneuver during the earth shadow, a real-time orbit determination method and strategy using adaptive square root information filtering is proposed, and the real-time precise orbit determination of the multi system navigation satellite based on the filtering is developed. The software system validates the correctness of the filtering and orbit determination algorithm and the performance of the software products through the measured data. The main research work and contribution of this paper are as follows: 1) from the three aspects of the satellite kinematics model, the observation model and the parameter estimation, the theoretical method of the precise orbit determination of the navigation satellite is systematically studied, including the satellite transportation. The dynamic equation discretization and perturbation model, the correction and linearization of observation error, the least squares estimation method used in batch processing and the square root information filtering method used in real time calculation. The paper focuses on the square root information filtering algorithm used in the real-time orbit determination, and gives the derivation of the filtering solution for the orbit determination process. The nonlinear error and the random function model.2 for the process noise are filtered and analyzed. The attitude model of the current navigation satellites and the inverse PPP algorithm for attitude angle estimation are analyzed. The attitude switching mechanism of the Beidou IGSO and the MEO satellite is deeply studied. The state model deviation will seriously affect the estimation of the precise orbit determination parameters, making the attitude angle of the reverse PPP estimation deviating from the actual value. An improved reverse dynamic PPP estimation method is proposed. The attitude angle changes during the attitude mode switching of the Beidou IGSO and the MEO satellite are estimated successfully. Based on the estimated satellite attitude angle, the Beidou IGSO is established. The empirical model of the yaw attitude of the MEO satellite and the accuracy of the model are verified by the precision orbit determination. In this paper, in the study of the real-time precision orbit determination of the Beidou satellite, all the related error terms are corrected by the yaw model.3), and the precision and quality control method of the real-time precision orbit determination model is studied. The fuzzy paste parameters are fixed in the multi system real-time orbit determination and filtering processing. The results show that, compared with the floating point, the accuracy of the GPS and the Beidou satellite's three-dimensional orbit accuracy is increased by about 2cm.4 after the fuzzy degree is fixed. The key problems of the detection, the determination of the precise orbit of the satellite during the maneuver and the rapid recovery of the precision orbit after maneuvering are discussed. The real-time detection of the satellite based on the prediction residual is proposed. After the detection of the satellite maneuver, the adaptive square root information filter is used to determine the real time orbit of the mobile satellite. Through the Beidou C05 and the C08 satellite The validity of the method is verified by the measured data during the maneuver. The result shows that the method can effectively detect the satellite maneuver, and can effectively avoid the filtering divergence caused by the orbit maneuver. The maximum residual error of the satellite corresponding to the station is within 0.3m during the maneuver, and the self adaptive filtering can maintain the continuity of the calculated parameters. The precision track recovery time after maneuver is greatly shortened, and the accuracy of the 3-6h orbit determination after the maneuver is restored to the normal level.5 before the maneuver. The analysis verifies the applicability of the real-time precision orbit determination filter algorithm for the GPS satellite in the shadow period. The results show that the real-time filter track of the earth shadow satellite is significantly better than the real-time orbit of the IGU super fast product. The process noise of the orbit parameters during the filtering calculation during the increase of ground shadow can further improve the three-dimensional orbit accuracy of the GPS BLOCK IIA earth shadow satellite. Based on the integrated navigation data processing software (PANDA) platform of the Wuhan University, the real-time precision orbit determination system of the multi system navigation satellite based on the square root information filtering is developed. The data is verified and analyzed by the method proposed in this paper and the developed software system. The results show that, compared with the IGS post precision orbit, the GPS and GLONASS real-time tracks are less than 10cm, respectively, for 6.7cm and 9.3cm. Beidou IGSO and MEO SLR, and GEO satellites SLR check the average deviation is 20.7cm, compared to the events. The systematic deviation from the SLR is reduced by about 20cm. By using two schemes of real-time filtering orbit and forecast orbit, it is proved that the filter track can effectively avoid the clock difference jump problem caused by the prediction of the discontinuous orbit. Finally, the software is solved in real time based on the dynamic precision single point location calculation example. The product has been verified. The results show that the real-time product can significantly improve the dynamic positioning accuracy of the Beidou single system compared to the real-time product based on the forecast orbit. The positioning accuracy of the horizontal 3cm and the elevation 5cm can be realized by the multi system precision positioning user.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P228.4

【相似文献】