【作者】 靳文瑞；

【导师】 战兴群；

【作者基本信息】 上海交通大学 ， 精密仪器及机械， 2009， 博士

【摘要】 低成本航向确定技术在民用船舶导航上的应用一直是国内外导航界的研究热点。利用GNSS实现航向指示的设备,称为卫星罗经(GNSS罗经),为船上其他设备(如AIS、VDR、ARPA)提供实时的航向信息,具有无累积误差、不受磁场分布影响、体积较小、价格低等特点,可作为中小型船只电/磁罗经的替代设备。利用载波相位差分测量实现多天线GNSS姿态/航向确定,关键在于初始整周模糊度解算和姿态/航向确定算法。在国家863项目“长航时高动态条件下高精度组合导航技术研究”(No. 2006AA705320)等课题的资助下,本文开展了基于GNSS姿态测量和其他姿态传感器的组合问题研究,重点放在单基线卫星罗经技术及组合的关键理论和实验技术研究,这将作为集成卫星罗经产品的理论和实验基础。本文主要研究思路及工作体现在五个方面:(1)调研、分析国内外GNSS组合姿态测量和卫星罗经技术,结合实验室现有研究基础,分析卫星罗经主要技术要求,提出GNSS单基线姿态测量与低成本磁传感器、INS组合方案。(2)基于当地水平坐标系下的差分姿态方程,研究了GNSS姿态测量误差,着重开展了多路径误差的理论和实验研究,提出了差分姿态方程的ADOP概念和表达式。(3)考虑可能出现的干扰情况,采用低成本三轴磁强计和单基线GNSS姿态测量进行组合。针对磁强计受到的外界干扰,寻求有效的误差补偿算法。搭建实验平台,开展组合航向测量的理论仿真和实验研究。(4)对于一些要求较高的场合,研究双天线测姿与低成本INS组合的方式和技术实现手段。在改善系统航向输出精度和可靠性的基础上,研究了INS与GNSS测姿的相互辅助技术,建立相应的量测方程。同时,搭建实验平台,开展相关的算法研究。(5)在上述研究基础上并结合已有工作,设计并改进了软、硬件试验应用系统,开展了大量静态、动态试验工作及数据分析处理,得到不同场景下实验具体结果。本文的关键技术研究和创新性有三方面:(1)研制了GNSS组合姿态测量系统。对多路径分析和单差姿态方程的姿态精度因子ADOP进行理论分析及实验研究,优化GNSS姿态测量的实现算法,提高了系统的可靠性和精度。(2)建立单基线GNSS与低成本磁强计的观测方程并优化滤波设计,改善载体组合姿态/航向的估算精度以及数据连续性。提出将磁强计给出的航向角粗估值约束模糊度函数搜索范围,减少搜索计算量。(3)研究双天线测姿与INS组合的结构形式采用同位于一条基线的深度融合方式。将INS和双天线测姿进行进一步分析,构造新的误差观测方程,并用Unscented卡尔曼滤波(UKF)进行处理。结合本文的单差姿态方程,利用INS初始测量的姿态角作为粗估量,可在整周全域搜索中,缩小整周模糊度函数的搜索范围,减少运算量,提高实时性。本文的研究结论主要有四点:(1)差分姿态方程和模糊度函数法的组合应用,提高了整周模糊度的实时性和可靠性。大量静态、车载动态实验表明这种组合改进方法较传统方法有效缩减了计算量,并且姿态/航向精度较高、数据稳定。(2)在开阔环境下,利用单差姿态算法和模糊度求解方法,分别计算引入多路径误差前后的姿态角,统计结果表明姿态角的标准差和均值变化不大,而在复杂环境下且同样的试验条件下,保持基线位置相同,多路径对姿态估算的影响几乎是相同,且通过作差可消除。通过对姿态ADOP的分析推导,在算法实现上需要注意一些特殊位置的处理。(3)低成本磁强计和GNSS组合测量航向可有效提高整个系统数据输出的连续和稳定性,而且两者组合结构和滤波易于实现、磁强计误差补偿易于工程实现。相比与单一GNSS测姿系统,组合后系统的成本增加有限。(4)低成本INS和GNSS组合姿态测量的数据精度高,而且能利用INS的初始信息提高GNSS的整周模糊度解算的效率,二者的相互辅助提供了系统的整体稳定性,通过Unscented卡尔曼滤波可得到较高的精度。与磁强计组合相比,其劣势在于成本增加较多,适用于更高需求的用户。利用本文的理论和技术手段,可针对不同的指标要求,实现不同的系统,满足实际需要。更多还原

【Abstract】 Low-cost direction determination for civil ship has long been an issue of great interest in navigation. Satellite compass, or GNSS compass, an equipment to indicate direction using GNSS technologies and provide realtime heading information for other devices (AIS, VDR and ARPA), becomes a major alternative for the traditional electronic-/magnetic-gyrocompass because of its non-accumulation error, little influence of earth magnetic and low cost.The key to the direction determination by GNSS carrier phase measurements lies in the algorithms of solving integer ambiguity and attitude/heading. What is described in this thesis is based on the results collected during the extended research of which is a 863 project named‘High precision integrated navigation technology under long endurance and high dynamic conditions’(No. 2006AA705320) and other related projects. The major topic is integration of GNSS and various sensors for attitude determination and special emphasis has been put on the theoretical analysis and experimental verifications of single-baseline satellite compass, which is prepared for preliminary report before production.The major contributions and roadmap of the thesis are summarized as follows:(1) Collection and summary of all the related literature and previous work. With this information, and taking into account the hardware limits, I specify the specifications of the GNSS compass to be researched and propose how to implement a low-cost attitude determination system.(2) The attitude determination is done using differential attitude equations developed in a local level frame. A detailed derivation and analysis of ADOP formula is given. The multipath is considered the primary error source and simulation and experiments show the feasibility of mitigating multipath using piecewise difference.(3) Considering the jam cases, the low-cost three-axis magnetometer and sigle-baseline GNSS attitude determination were ingerated. For the influence of earth magnetic field, error compensation algorithms were investigated deep. The test platform was built and theory simulations and experiments were carried out.(4) For the strict situation, double-antenna GNSS attitude determination and low-cost INS integated technology were investigated. The mutually supporting of the two systems is important for the whole system and the measurement equation and unscented kalman filter (UKF) were built up.(5) Based on all the above mentioned, a hardware and software prototype is worked out for improving the performance through diverse experiments, static or dynamic. Results have been given and grouped by different scenarios and conditions.The key technology and innovativeness of the thesis are summarized as follows:(1) The GNSS integrated attitude determination system has been developed. Based on the research of differenc attitude equation of local level fram (LLF), the error problems of GNSS attitude determination were investigated deep. The attitude dilution of precision (ADOP) of sigle-difference attitude equation was analysed and derived and some useful deduction could be used in the algorithm implementation. The multipath error is the main error source of carrier phase attitude determination. The theory model of multipath was given and the tests in simple and complicated enviroments have been carrier out.(2) The GNSS attitude determination equations and magnetmeter linearization equation have been built up and filted by EKF. The attitude/heading precision and continuity become better. The heading output of magnetmeter could be used for constraint condition of integer searching range and the calculation load was reduced greatly.(3) Based on single baseline, the deep integration structure of GNSS attitude determination and INS have been built up and filted by unscented kalman filter (UKF). The attitude output of INS could be used for constraint condition of integer searching range and the calculation load was reduced greatly. The mutually supporting of the two systems is important for the whole system.The research conclusions of the thesis are summarized as follows:(1) The integation of difference attitude equation and ambiguity function method (AFM) has improved the real-time and reliability of integer ambiguity resolution. A number of experiments demonstrate that this improved approach significantly outperforms the traditional ones in terms of the computation load. Compared with the traditional approach, the efficiency of the improved one is faster than the traditional one on average, with equivalent performance in reliability and accuracy.(2) In open environment, the standard deviations and means of multipath error have little change. And in complicated environment, the influence of multipath has the same result and could be removed easily under the same test conditon. Considering the ADOP, some processes should be taken into accout in some special positons.(3) Low-cost three-axis magnetometer and GNSS integation improves the continuity, reliability and precision and could be implemented in simple way. The cost of the whole system is not more expensive than only GNSS attitude determination.(4) The initial attitude output of INS could be used for constraint condition of integer searching range and the calculation load was reduced greatly. The mutually supporting of the two systems provides the better performance. The cost of the whole system increases great and the high precision and good reliability coule be obtained, especially in some advanced application. Finally, different costs have different performance figures depended upon the user’s requirements and choice.更多还原