An approach of DVL-aided SDINS alignment for in-motion vessel

An in-motion alignment algorithm of strapdown inertial navigation system (SDINS) aided by Doppler velocity log (DVL) is described. As the bias and scale factor errors of DVL cannot be estimated by using conventional algorithm, error model of DVL along axes on local level navigation frame is developed while the ship is sailing at a constant speed. Analysis shows that by using this error model in Kalman filter, the observability of state variable can be improved by the angular motion of the ship. Simulation results show that the DVL measurement error can be estimated precisely and the accuracy of the DVL-aided in-sail alignment can be enhanced greatly by using the proposed approach.     

A Kalman filter algorithm based on exact modeling for FOG GPS/SINS integration

The Kalman filter is widely applied in fiber optic gyro (FOG) inertial integrated navigation system. To solve the problem of hard acquirement of Kalman filter parameters, a novel algorithm for FOG GPS/SINS integration navigation based on exact modeling is proposed in this paper. The models of inertial sensors using Allan variance analysis are established in proposed algorithm and the precise Kalman filter model is obtained based on the correspondence between Allan variance coefficients and inertial sensors parameters. The simulation and experimental results show that Kalman filter parameters can be obtained for GPS/SINS integrated navigation system precisely and efficiently based on Allan variance modeling method, and the algorithm has reference value for theoretical perfection and engineering applications.     

AR模型辅助SINS／GPS组合导航的实验研究

激光陀螺的随机漂移噪声类似于白噪声,可以采用AR（2）模型进行数字滤波来减小其对激光陀螺精度的影响。首先介绍了AR模型,然后利用IMU单元三组陀螺信号的AR（2）模型给出了车载SINS／GPS组合导航系统误差模型,并在GPS的辅助下,对SINS／GPS组合导航进行了实验研究。最后利用Kalman滤波器对车载SINs／GPS组合导航实际测量数据进行了离线的半实物仿真。实验结果表明,采用AR（2）模型辅助的SINS／GPS组合导航系统能够得到较高的姿态精度,并能有效抑制速度误差的发散。     

捷联惯性导航系统误差工程化分析方法

针对设计捷联惯性导航系统时系统指标要求合理选择惯性传感器的问题,提出一种捷联惯性导航系统误差分析方法,建立了系统在不同工作条件下的误差模型,给出了在设计捷联惯性导航系统时,纯惯性导航时间小于2 min、位置误差小于100 m时选择陀螺和加速度计的方法。     

用单轴转台标定光纤陀螺捷联系统的方法

针对以六面体作为安装支架的三轴光纤陀螺捷联系统,提出了一种用单轴转台作为标定设备的低成本标定方法。六面体支架有3个面为未安装陀螺的平面,需用游标量角器量出这3个面的相互夹角,并根据这3个面建立机体坐标系,在该坐标系下给出了陀螺输出模型。标定时依次将六面体的3个平面贴于单轴转台的台面进行标定实验,推导了光纤陀螺标度因数和安装误差的求解公式。对标定的精度进行了分析,并与传统的方法对比做了实验验证,结果表明该方法可满足系统要求。     

光纤陀螺随机误差建模与滤波方法研究

提出了一种适用于高精度光纤陀螺的静态输出信号建模的时间序列模型,建立了光纤陀螺随机误差的卡尔曼滤波器。结果表明,该建模和滤波方法有效地减小了FOG的误差,明显地降低了陀螺的随机漂移,提高了导航精度,具有较好的实用价值。     

基于激光测速仪的高精度定位定向技术

基于激光测速仪的工作原理、测量特性,结合惯性导航系统的工作特点,提出一种实现车体自主高精度定位定向的组合方法。推导了用于车载组合定位定向的三波束激光测速仪误差模型,结合捷联惯导误差模型,选取了组合卡尔曼滤波器状态量,并推导了组合导航量测模型。最后针对这种基于激光测速仪的组合定位定向方法进行了仿真计算,列出了相关计算结果,仿真结果验证了这种方法的正确性。     

基于激光多普勒测速仪的车载组合导航

 针对车载纯捷联惯性导航系统(SINS)导航精度随时间增长而降低的不足,提出了基于激光多普勒测速仪（LDV）这一新型速度传感器的组合导航方案。通过建立SINS/LDV组合导航系统的状态方程和量测方程,设计了系统的卡尔曼滤波器,并对组合导航系统进行了仿真模拟。结果表明：SINS/LDV组合方案能够有效减小SINS导航参数随时间的累积误差,可以实现全自主、高精度导航;当LDV测速精度为0.1%时,组合导航系统的位置精度提高了2个数量级,速度精度提高了1个数量级。     

小波网络辅助卡尔曼滤波的捷联惯导传递对准

初始对准精度是捷联惯导系统的主要误差来源之一。针对舰载机捷联惯导的传递对准模型准确建模困难,且测量噪声和过程噪声随舰船动态而变化,这样就会降低滤波的精度,卡尔曼滤波有一定的局限性,提出了将小波神经网络辅助卡尔曼滤波器用于惯导系统的传递对准。把能直接影响卡尔曼滤波估计误差的参数作为网络的输入,进过样本训练后,把网络的输出与经过卡尔曼滤波得到的结果相加,实现了捷联惯导的传递对准的滤波功能。这种新算法在实际应用中的非线性情况下优于传统卡尔曼滤波方法。仿真结果表明了其实用性和有效性。     

Rapid transfer alignment of laser SINS using quaternion based angular measurement

A novel rapid transfer alignment algorithm for laser strapdown inertial navigation system (SINS) is studied. Transfer alignment have typically relied on velocity measurements from the master SINS as the source of alignment information, but lever arm error must be compensated accurately while velocity information is utilized, all most every quaternion based error model is nonlinear, so nonlinear filtering algorithms are need, suffering from computational complex and large error. Aim at these problems, a novel improved rapid transfer alignment algorithm formulation is presented, applying quaternion to built the process and measurement models, the improvement employs a special manipulation of the measurement equation results in a linear pseudo-measurement equation, thus the classical linear Kalman filter is employed to estimate the state, need not lever arm error compensation, results in the reduce of computational burden. Observability analysis of this new transfer alignment algorithm has been done based on the piece-wise constant system (PWCS) method, results show that the presented algorithm can accomplish the initial alignment task perfectly. A transfer alignment simulation system is also developed for the evaluation and analysis of the presented algorithm, simulation results are confirmed with the theoretical conclusion, which can achieve the transfer alignment accuracy about 1 mrad within 10 s.     

多普勒计程仪作用距离估计

多普勒计程仪已成功应用于多种载体的导航,而其最大作用距离对于设计和使用都具有重要的意义。根据声纳方程各项的定义并根据多普勒计程仪工作时的特点,推导出不同条件下声纳方程中各项的计算公式,从而对多普勒计程仪的最大作用距离进行估计,最后将某型多普勒计程仪的相关参数代入推导的公式中,并进行计算得到理论计算值。同时还计算了多普勒计程仪在不同条件下的作用距离。     

基于Kalman滤波算法的陀螺仪动态漂移补偿研究

应用MEMS陀螺仪测量人体手臂运动姿态时,针对陀螺仪受线加速度干扰导致测量姿态发散的问题,提出基于Kalman滤波算法的姿态误差补偿方法;该方法首先将陀螺仪采集到的角速度通过方向余弦算法解算得到姿态角,并将陀螺仪动态漂移造成的姿态角误差视为时变信号,通过建立姿态角漂移误差的状态方程及观测方程,应用卡尔曼滤波算法,实现对姿态角漂移误差的估计,最终达到对陀螺仪动态漂移误差的补偿;实验与仿真结果表明,应用该算法能够有效的抑制线加速度干扰导致的陀螺仪测量的姿态发散,适用于陀螺仪对人体手臂运动姿态的测量。     

一种新的惯性／天文组合导航方法研究

针对传统的惯性／天文组合定位定向法不能有效修正惯性导航系统传感器误差所造成的导航误差，研究了一种新的惯性／天文组合导航方法。利用天文导航系统的量测，在初始对准后估计并补偿加速度计偏置误差，在组合导航过程中闭环修正陀螺漂移误差，进而提高组合导航的姿态、速度及定位精度。仿真结果表明了该方法的有效性，并通过与传统组合方法仿真结果的比较，证明了此方法的优越性。     

Coarse alignment for Fiber Optic Gyro SINS with external velocity aid

Random movements including angular and linear movements by sway action, together with deliberate velocities of ship maneuvers, are big challenges for coarse alignment of Fiber Optic Gyro (FOG) Ship Inertial Navigation System (SINS) on sailing ship. It is impossible to solve the problem mentioned above with traditional methods. So a new analytic alignment method is proposed in this paper, in which the gyro measurements can track body angular movements, an aiding velocity sensor can describe deliberate velocities of ship maneuvers, and the integral of the equation of the time rate of change of the maneuver velocity is used in computing a strapdown attitude matrix. The experiment results confirm the efficiency of the proposed method.     

激光陀螺捷联惯性导航系统误差分析及仿真计算

激光陀螺随机游走现象的存在，严重影响了捷联惯性导航系统的导航性能。本文用数学分析的方法推导出激光陀螺随机游走造成的系统导航误差标准偏差的解析表达式，以便定量地研究激光陀螺随机游走对系统精度的影响，并提出改进措施。同时按照给定的飞行轨迹和随机游走系数，进行了系统数学仿真计算，对仿真计算结果进行了分析。     

基于9DOF IMU的AUV惯性导航技术研究

水下机器人（underwater vehicle）惯性导航技术是目前机器人控制技术的难点,通过加装不同类型的IMU组件,可以实现水下机器人姿态、方位等参数的测量,并将这些参数作为反馈输入来实现水下机器人的精确控制。针对低成本微惯性传感器的应用特性,采用Sparkfun、Arduino Mega和Raspberry Pi,设计了基于Raspberry Pi集中处理、Arduino控制板分布式控制的微小型捷联惯导系统,实现了水下机器人惯性导航系统的全部导航和制导参数读取,包含位置坐标、线速度、角速度、姿态角、方位角等信息,通过水池试验表明应用表明本系统满足Eco-dolphin的水下定航控制要求。     

机载北斗/GPS/SINS组合导航系统软硬件设计

针对单一导航导航系统在导航精度、稳定性、设备成本以及导航信息完备性等方面的局限性,设计了卫星导航/惯性导航组合导航系统。针对GPS导航系统受制于人及北斗导航系统发展尚不完善的特点,提出了基于北斗/GPS/SINS的军用机载组合导航系统软硬件设计。搭建了北斗/GPS/SINS组合导航系统硬件平台,采用基于不确定度的加权平均数据融合算法提高组合导航系统的导航可靠性和准确性。仿真结果表明,该组合导航系统稳定性好,可靠性高,定位准确。     

体积速度匹配分布源边界点法的特解源位置优化方法研究

在分布源边界点法中,选择特解源及特解源位置对声场计算的精度具有很大的影响。为减小声场计算的误差,提出了一种确定特解源位置的优化方法。在该方法中,采用三极子作为特解源,以1%体积速度相对误差对结构声辐射计算的上限频率进行预测,然后在计算上限频率范围内通过体积速度匹配搜索,得到体积速度相对误差最小意义下的特解源优化位置,在该优化位置处构造声压与表面体积速度之间的传递矩阵来计算声场,以减小计算误差。数值仿真结果表明:在求取的计算上限频率范围内,特解源处于优化位置时,计算误差得以显著减小。当振速测量存在一定误差时,采用该方法仍可将计算误差控制在5%以内。      

光纤陀螺仪零漂信号的Allan方差分析

介绍了光纤陀螺零漂实验的设备环境,硬件和软件的构成及数据采集过程。在测得光纤陀螺零漂信号的基础上,运用Allan方差理论对陀螺信号进行定量的分析,得到了光纤陀螺5个误差源系数的大小,并根据误差源的产生机理,找到了光纤陀螺硬件存在误差的部分,提出了光纤陀螺的改进方案。     

Position optimization of particular solution sources for distributed source boundary point method by volume velocity-matching

Choosing particular solution source and its position have great influence on accuracy of sound field prediction in distributed source boundary point method.An optimization method for determining the position of particular solution sources is proposed to get high accuracy prediction result.In this method,tripole is chosen as the particular solution.The upper limit frequency of calculation is predicted by setting 1%volume velocity relative error limit using vibration velocity of structure surface.Then,the optimal position of particular solution sources,in which the relative error of volume velocity is minimum,is determined within the range of upper limit frequency by searching algorithm using volume velocity matching.The transfer matrix between pressure and surface volume velocity is constructed in the optimal position.After that,the sound radiation of structure is calculated by the matrix.The results of numerical simulation show that the calculation error is significantly reduced by the proposed method.When there are vibration velocity measurement errors,the calculation errors can be controlled within 5% by the method.