Inertial navigation system synthesis approach and gravity-inducederror sensitivity

A design criterion for improving the performance of the speed-damped inertial navigation system is presented. The single-axis speed-damped system is approached by optimizing the response of the system to a step-function disturbing signal. Butterworth, integral of time-multiplied absolute-value of error (ITAE), and solution-time standard forms are assumed to be the figures of merit for optimizing the system performance. The steady-state RMS (root-mean-square) gravity-induced navigation errors that are excited in the speed-damped system are determined for two gravity uncertainty models. The proposed figures of merit are compared. These comparisons reveal the sensitivity of predicted navigation errors to uncertainties in the gravity statistics, and simplify the choice of a suitable figure of merit for use in the design and error analysis of inertial navigation systems     

陀螺RRW在惯导系统中的误差传播特性

角速率随机游走是高精度光纤陀螺的一项主要随机误差源,对惯性导航系统的误差有着较大影响。分析了角速率随机游走的统计特性,推导了角速率随机游走引起的惯性导航系统姿态、位置误差的解析表达式,研究了静基座环境下的惯性导航系统在长时间导航环境下的随机误差传播规律,对角速率随机游走作用下的惯性导航系统误差进行了仿真与实验,验证了所推导公式的正确性,对惯性导航系统的设计与误差分析具有一定的参考意义。     

一种基于实测飞行轨迹的惯导误差分析方法研究

针对传统蒙特卡罗仿真方法用于惯导误差分析时计算量大且参数调整不便的问题,提出了采用Kalman滤波的状态均方误差预测公式结合惯导误差传播方程进行误差协方差分析的新方法。该方法将惯导总误差分解为各种不同误差因素的线性组合,且各误差因素之间是相互独立的,误差计算和参数调整都非常简单方便。以一组实测飞行轨迹数据为例,利用所提协方差分析方法进行误差分解,并将结果以多种形式直观展示,显示了新方法在误差分配和精度评估中的优越性。     

纯惯导中制导误差分析

针对洲际弹道导弹,在分析加速度计测量误差和陀螺漂移误差对导弹视加速度影响的基础上,给出了中制导段惯性系统对速度和位置的误差传递模型,对给定的惯组误差系数偏差进行了纯惯性导航制导误差计算。仿真结果表明,纯惯导中制导对洲际导弹落点精度影响比较大。该算法可用于纯惯性中制导方案设计。     

一种长航时惯导定位误差评估的新方法

针对长航时惯导传统定位误差评估中存在的问题,提出了一种新的基于惯导误差传播函数拟合的定位误差评价新方法。基于长航时惯导系统定位误差传播模型的特点,采用三角函数建立了误差传播拟合函数,主要包含舒拉周期、地球周期和傅科周期,反映了惯导的长期误差特性。提出了惯导误差契合度的定义和计算方法,实现了对长航时惯导系统定位误差的量化评估。对两套精度大致相同的长航时惯导舰载实验数据进行了对比分析,结果表明新的评估方法能够给出更合理的定位性能优劣判断。最后,针对长航时自主导航需求提出了综合导航技术的改进建议。     

捷联惯性导航系统动静态误差特性分析研究

捷联惯性导航系统动静态误差特性是基于惯性的组合导航系统的主要误差来源。为此,根据捷联惯性导航系统的误差状态方程,本文分析了不同动静态情况下的捷联惯导系统的误差漂移特性。针对静基座和动基座的不同特点,分别采用了特征根和基于数值仿真分析的方法,并建立了相应的误差特性分析模型。重点研究了陀螺常值漂移、加速度计零位偏置和随机性误差对惯性导航系统误差漂移特性的影响;全面分析验证了惯性导航系统的动静态误差特性。本文的研究工作将为惯性组合导航系统误差分析建模提供了有益的参考。     

基于联邦滤波的惯导/北斗/里程计紧 组合导航算法研究

针对地面载体长时间复杂应用环境对导航系统精确性和可靠性的要求,提 出一种基于联邦滤波器的惯导/北斗/里程计紧组合导航算法。在分析惯导、北斗、里程 计导航系统特点的基础上,建立了组合导航系统的误差状态模型和量测模型,采用联邦 滤波器实现了三者的紧组合容错系统设计,分别对子系统无故障、北斗及里程计出现故 障情况下进行仿真验证。结果表明,将联邦滤波理论应用于惯导/北斗/里程计紧组合导 航系统可以提高导航性能和系统的容错能力。     

基于人体运动学辅助的可穿戴式行人导航系统

针对行人导航定位问题,研究了基于人体运动学辅助的可穿戴式行人导航系统实现的关键技术。首先基于人体运动学原理构建了零速检测模型,使用最优综合判断条件有效检测出对应的零速时刻,实时进行速度和姿态的更新修正。在检测到零速时刻时,将速度误差、位置误差作为观测量,经Kalman滤波估计惯导系统误差并进行反馈校正,抑制惯导系统的误差,提高导航定位精度。研制了集信息采集、数据传输、导航解算与监控显示于一体的可穿戴式行人导航系统,可对行人的运动状态进行实时监控。所设计的基于人体运动学辅助的可穿戴式行人导航系统,平均定位误差小于行走距离的1.1%,最大不超过1.7%,验证了本系统的可靠性和适用性。     

单轴旋转惯导系统误差特性分析

旋转调制技术能够抑制陀螺和加速度计的误差,提高惯性导航系统的导航精度。从捷联惯导系统的误差方程出发,推到出了单轴旋转惯导系统的误差传播方程,在此基础上分析了旋转调制的基本原理。分别对陀螺和加速度计常值偏差、标度因数误差、安装误差和转台安装误差等在旋转调制下的影响进行了研究,仿真分析了旋转调制提高系统导航精度的作用,最后在实验室条件下做静止导航实验进行了验证。研究的结果能为单轴旋转惯导系统的研究和开发提供一定的理论参考。     

Drag derived altitude aided navigation method

The navigation problem of the lifting reentry vehicles has attracted much research interest in the past decade.This paper researches the navigation in the blackout zone during the reentry phase of the aircraft,when the communication signals are attenuated and even interrupted by the blackout zone.However,when calculating altitude,a pure classic inertial navigation algorithm appears imprecise and divergent.In order to obtain a more precise aircraft altitude,this paper applies an integrated navigation method based on inertial navigation algorithms,which uses drag derived altitude to aid the inertial navigation during the blackout zone.This method can overcome the shortcomings of the inertial navigation system and improve the navigation accuracy.To further improve the navigation accuracy,the applicable condition and the main error factors,such as the atmospheric coefficient error and drag coefficient error are analyzed in detail.Then the damping circuit design of the navigation control system and the damping coefficients determination is introduced.The feasibility of the method is verified by the typical reentry trajectory simulation,and the influence of the iterative times on the accuracy is analyzed.Simulation results show that iterative three times achieves the best effect.     

Kalman Filter Design Considerations for Space-Stable Inertial Navigation Systems

Terrestrial inertial navigation is typically performed using an instrumented platform stabilized in a ?local-level? configuration for convenient generation of geographic navigation information. The local-level geographic reference must be maintained by torquing the system gyros, a requirement which may be incompatible with high-precision inertial sensors currently under development. Gyro torquing in a gimballed navigation system can be avoided by employing a ?space-stable? mechanization of the platform where an inertial, rather than geographic, reference is used for navigation calculations. The software design problems associated with this concept, especially those related to the application of Kalman filtering, are the principle focus of this paper. Although the space-stable configuration has been used extensively for spacecraft navigation and guidance, it has not been widely applied to terrestrial navigation, either for air or marine applications. The chief problem in this application is to perform navigation in local-level coordinates, using system outputs generated in an inertial reference frame. It can be demonstrated that, although the navigation system error dynamics are identical for the local-level and space-stable configurations, the dynamics of the sensor errors which drive these systems are quite different. These differences in sensor error propagation characteristics impose new requirements for the design of procedures to accomplish system calibration, alignment, and reset. This paper outlines a Kalman filtering approach which is applicable to all of the above procedures, and presents numerical results to demonstrate its effectiveness.     

The Psi-Angle Error Equation in Strapdown Inertial Navigation Systems

A detailed development is presented of the psi-angle vector differential equation as applied to the error analysis of strapdown inertial navigation systems. The coordinate systems involved and the psi misalignment vector are clearly defined. It is proven that apart from a sign change the psi-angle differential equation in the error analysis of strapdown inertial navigation systems is identical to the one used in conventional gimbaled inertial navigation systems.     

旋转惯导中加速度计尺寸效应误差分析及补偿

 对旋转调制惯导转位过程中系统精度受加速度计尺寸效应影响的问题进行了研究。通过分析尺寸效应引起惯导系统(INS)导航误差的机理,推导了尺寸效应作用下加速度测量误差与速度误差的解析表达式。根据理论分析结果,分别给出了以速度误差和加速度误差作为观测量进行尺寸参数辨识的方法,并进行了必要讨论。结合旋转惯导转位过程中的速度误差特征,选取加速度测量误差为观测量对尺寸参数进行试验标定,尺寸参数辨识精度优于1.29 mm(1σ)。在此基础上给出了尺寸效应误差补偿方法,并在不同初始方位下对补偿效果进行试验验证,结果表明,通过尺寸效应补偿可以有效提高旋转惯导转位过程中的速度精度。     

SINS/DVL水下组合导航系统的误差分析与改进技术

探讨了一种适用于SINS/DVL组合导航系统的滤波原理,通过分别建立捷联惯导系统误差模型和多普勒误差模型,利用间接卡尔曼滤波原理和反馈校正法,对系统进行仿真与分析,由惯性器件的误差方差通过导航系统的误差模型得出导航参数的误差方差,结果表明,该组合导航系统的定位精度要远远高于单纯捷联惯导系统。同时,针对SINS/DVL组合导航系统工作特点及特定情况下AUV的定位精度要求,提出了一种GPS辅助SINS/DVL组合导航系统导航定位的方案。     

Propagation and System Accuracy Impact of Major Sensor Errors on a Strapdown Aircraft Navigator

A strapdown system is considered as an unaided inertial navigator aboard an aircraft. Presented here are simulation results detailing the propagation of navigation errors (in nautical miles) due to strapdown sensor errors for four trajectories. They indicate the type of performance that can be expected from a strapdown system utilizing good ?off the shelf? gyros and accelerometers, and dramatically illustrate the improvements necessary in these components to obtain navigation performance comparable to that available from a good gimballed inertial system. The total navigation error for each trajectory is broken down to show the contribution from each of the various error sources. This breakdown quickly reveals which are the critical error sources for a given trajectory class, and also points up the relationship that exists between each individual error source, aircraft maneuvers, and the resulting navigation error. Several of the error mechanisms are discussed at length and a set of linearized differential equations which can be used to analyze error propagations is presented. These results should be of particular interest to the system designer who is faced with the problem of specifying the sensor error parameters necessary to meet mission performance requirements. With an analysis similar to the one presented here, but structured around his own expected mission trajectories, the designer should be able to confidently predict system accuracies and intelligently perform tradeoffs on the critical system parameters.     

Strapdown inertial navigation using dual quaternion algebra: error analysis

In a strapdown inertial navigation system (INS), the general displacement of a rigid body is traditionally separately modeled and analyzed, i.e., direction cosine matrix or quaternion for rotation analysis and vector for translation analysis. As a subsequent work of a companion paper (Wu et al., 2005), this paper adopts dual quaternion algebra, a most concise and unified mathematical tool for representing the general displacement of a rigid body, to analyze error characteristics of the strapdown INS. Two new error models in terms of quaternion algebra are developed: the additive dual quaternion error (ADQE) model and multiplicative dual quaternion error (MDQE) model. Both are expected to facilitate the future inertial navigation-based integrated navigation filter.     

惯性+星光折射定位组合导航技术研究

由于现有惯性器件精度水平有限,纯惯性导航误差较大,因此需要采用组合导航的方式来提高导航精度。目前,全自主组合导航方式中传统的惯性+星光定姿组合导航方法只能实现定姿,不能实现定位,无法修正加速度表测量误差引起的惯性导航误差,故在精度上可提升空间有限。为此,提出了一种惯性+星光折射定位组合导航方法,重点从星光折射定位原理、大气折射模型、非线性滤波和选星策略几个方面进行论证及分析。通过理论分析与数学仿真相结合的手段,验证了星光折射定位原理的正确性及工程可行性,可将自主导航精度提升至100m,从而为进一步提高自主导航精度提供了一种技术途径。     

Navigation message designing with high accuracy for NAV

Navigation message designing with high accuracy guarantee is the key to efficient navigation message distribution in the global navigation satellite system（GNSS）. Developing high accuracy-aware navigation message designing algorithms is an important topic. This paper investigates the high-accuracy navigation message designing problem with the message structure unchanged.The contributions made in this paper include a heuristic that employs the concept of the estimated range deviation（ERD） to improve the existing well-known navigation message on L1 frequency（NAV） of global positioning system（GPS） for good accuracy service; a numerical analysis approximation method（NAAM） to evaluate the range error due to truncation（RET） of different navigation messages; and a basic positioning parameters designing algorithm in the limited space allocation. Based on the predicted ultra-rapid data from the ultra-rapid data from the international GPS service for geodynamic（IGU）, ERDs are generated in real time for error correction.Simulations show that the algorithms developed in this paper are general and flexible, and thus are applicable to NAV improvement and other navigation message designs.     

车载捷联惯导与里程计组合导航技术研究

惯导的误差随着时间增长是积累的,可采用里程计辅助捷联惯导构成纯自主的车载组合导航系统.利用捷联惯导的速度和里程计测量的速度之差作为观测量,通过卡尔曼滤波技术校正惯导的导航参数,可以有效地抑制惯导误差的积累,提高导航参数的精度.本文推导了组合导航系统的模型,从理论上用特征值方法分析了系统的可观测度,进而设计轨迹进行了仿真...     

利用TERCOM与ICCP进行联合重力匹配导航

重力匹配导航算法对提高匹配效率和精度具有重要意义,是水下匹配导航技术的热点问题。对已有的重力辅助惯性匹配导航算法开展了研究,在此基础上提出了一种新的基于ICCP与TERCOM相结合的重力匹配导航算法。该算法在已有改进算法的基础上,对惯性导航提供的采样间隔航距以及ICCP匹配航距,和改进TERCOM匹配航距进行了联合对比分析。通过设置限差,搜索出TERCOM匹配误差较大点,并用ICCP对应匹配点进行替换,反复搜索和替换,最终生成由两种算法结合的新匹配轨迹。在TERCOM匹配初始误差较小的情况下,该方法对TERCOM算法匹配精度的提升依赖于ICCP匹配结果。仿真结果表明:对于TERCOM出现明显误匹配且ICCP匹配结果较好时,该算法可大大提高重力匹配精度,距离误差由2000m降至870m,X轴方向由TERCOM匹配平均误差的1370m降至530m,Y轴方向由TERCOM匹配平均误差的1900m降至640m,从而更好地满足了水下导航的需求。