支持精密着舰的海基区域增强系统完好性监测方法研究

Since the pseudorange differential positioning based area augmentation system has limitation in satisfying the Required Navigation Performance (RNP) of Precision Shipboard Landing (PSL), this proposed project explores the integrity monitoring method of Sea-based Area Augmentation System (SAAS) based on carrier phase differential positioning to support PSL with high reliability. As diversity of integrity risk resources originate from shipboard landing environment, the Bayesian criterion is applied to establish the integrity risk allocation framework. In terms of multiple error resources with non-ideal distribution in the range domain, the inflation coefficients based sigma inflation approach is developed to address the issue of compensating the non-zero mean Gaussian error and the non-Gaussian error. Since the reliability of Integer Ambiguity Resolution (IAR) in the ambiguity domain is of significance to determine the positioning accuracy and the availability, according to the critical calculation process of IAR, the integrity monitoring is implemented to verify the reliability of IAR. In order to improve the reliability of the baseline solution, the position domain-based multiple reference consistency check is developed to monitor the reference receiver's fault, integrity monitoring approach based on the total least square theory can thereafter be explored to monitor the baseline flexure. Through the research project, the performance of SAAS could be ultimately enhanced so as to satisfy the high reliability of PSL, and be the theoretical foundation for the integrity monitoring of high precision positioning based on satellite navigation as well.

由于基于伪距差分定位技术的区域增强系统无法满足精密着舰所需导航性能的要求，在海基区域增强系统的架构下，本项目拟研究基于载波相位差分定位技术的完好性监测方法以支持高可靠性的精密着舰。考虑到着舰环境下完好性风险源的多样性，运用贝叶斯准则建立完好性风险分配体系。针对测距域内多种类型的非理想误差，采用基于膨胀系数集的sigma膨胀算法补偿非零均值高斯误差和非高斯误差。鉴于模糊度域内整周模糊度的可靠性是决定定位精度和可用性的重要因素，依据整周模糊度解算的关键步骤，探索检验整周模糊度可靠性的完好性监测方法。为提高基线解的可靠性，研究定位域的多参考一致性检测算法监测参考接收机故障，在此基础上利用基于总体最小二乘理论的完好性监测方法实现基线形变量的监测。通过本项目的研究，使得海基区域增强系统能够支持高可靠性的精密着舰，并为基于卫星导航精密定位的完好性监测奠定理论基础。

海基区域增强系统完好性监测技术是卫星导航应用于精密着舰关键之所在。以满足精密着舰所需的精度、完好性、连续性和可用性等指标为目标，开展了以下研究工作：（1）基于电离层无关和几何无关相结合的观测量组合方案，分析了各类风险源的传播规律。由于修正误差包含非零均值高斯误差和非高斯误差时，在满足误差覆盖的约束条件下，将sigma膨胀、均值膨胀和非高斯膨胀相结合，通过选取最优膨胀系数集提高系统的可用性水平。仿真实验证明即使在关键卫星发生故障的情况下，基于膨胀系数集的Sigma膨胀算法能够将系统可用性至少提高至95%。（2）在差分定位方面，通过采用码观测量和载波相位观测量实现单历元在航定位以消除整周跳变对定位实时性的限制。针对北斗双频整周模糊度解算可靠性，基于完好性监测的思想设计双重检测统计量，实现对模糊度检验所存在的I类和II类错误的同步控制。实验证明，与传统基于固定门限和固定失败率的模糊度检验方法相比，所提出的方法可将定位精度和连续性分别提高约8cm和11%，从而验证所提出模糊度检验方法在控制模糊度固定I类和II类错误的有效性。（3）针对传统观测量域基于极大使然准则的B值在多参考一致性检测应用时完好性监测性能较低的缺点，设计基于Kalman滤波的位置域特征检测值取代传统B值以提高多参考一致性检测与识别性能。构建基于多考接收机故障假设的系统完好性风险模型，在Kalman滤波中引入自适应衰减调节因子实现对各类基线形变的检测，并维持滤波稳定性和完好性风险之间的平衡。实验证明在输入各类型故障时，在可用性损失可接受的范围内，基于Kalman滤波的多参考一致性检测算法可有效提升基线形变检测与识别性能。.通过本项目的实施，完成了计划书规定的研究内容，并对关键技术进行攻关，除此以外还解决了研究过程中的其他相关的技术问题，为利用海基区域增强系统支持精密着舰提供理论和技术依据。