联合惯导的GPS周跳探测与修复算法研究

发布时间：2018-07-03 19:48

本文选题：MEMS惯导 + 姿态更新　；参考：《西南交通大学》2017年硕士论文

【摘要】：正确的探测与修复周跳是保证GNSS(Global Navigation Satellite System)高精度导航定位服务的前提。在一些特殊环境(城市街道、高边坡路、隧道等)动态测量时,周跳的频繁发生导致无法定位或定位结果错误。常用周跳探测的方法都依赖于GNSS观测值,在GNSS失锁以后,仅靠自身的观测值很难可靠的探测出周跳发生的位置及大小。GNSS接收机的采样率一般为1Hz,数据采样频率低,很难满足高动态应用环境。惯性导航系统不受外界干扰,数据采样率高,短期内精度较高。本文引入惯导观测值,提出了一种联合惯导的GPS周跳探测与修复算法。本论文旨在GPS联合惯导解决在复杂环境下大量卫星失锁时对GPS周跳的探测与修复,实现GPS高精度实时动态定位。围绕这一核心目标,本文主要从算法设计和数据处理的角度出发,深入研究,建立了 MEMS(Microelectromechanical System)惯导空间轨迹跟踪的数学模型,提出了联合惯导约束GPS观测方程,建立星间单差的历元差分模型,完成对周跳的探测与修复。本文主要研究内容和成果有以下几个方面:(1)、完成MEMS惯导姿态更新与空间轨迹跟踪的算法。在姿态解算方面,利用四元数法解算得到对应时刻的航向角、俯仰角、横滚角。在空间轨迹跟踪方面,完成载体坐标系下加速度到地理坐标系下的转换,利用时域二次积分的方法,确定MEMS空间运动轨迹。针对该算法,通过仿真平面与斜坡运动的理论数据计算,结果偏差在10-3m内,表明MEMS惯导空间轨迹跟踪算法在理论上准确可靠。(2)、完成MEMS惯导实测数据的处理。完成对三轴加速计、陀螺仪的零偏标定,对实测数据的信号采用中值滤波降噪,加入随时间变化的动偏改正项。经修正后,MEMS实测数据在10s内计算结果,与RTK数据比较,在N、E方向误差小于3m。(3)、提出联合惯导的GPS周跳探测与修复的算法。采用了 GPS星间单差历元差分的观测模型,引入实测MEMS惯导观测数据,建立联合惯导GPS周跳探测数学模型,根据最小二乘原理,结合LAMBDA整周模糊度搜索法,实现周跳的探测与修复。采用车载实测数据进行实验,通过对比有无惯导约束的情况,实验结果表明:在惯导约束下,可以成功的探测修复大量卫星发生的周跳,并可以探测修复发生的小周跳。
[Abstract]:Correct detection and repair of cycle slips is a prerequisite for GNSS (Global Navigation Satellite system) high precision navigation and positioning service. In some special environment (city streets, high slope roads, tunnels, etc.) dynamic measurement, the frequent occurrence of cycle slips lead to unable to locate or locate the results wrong. The commonly used methods of cycle slip detection depend on GNSS observations. After GNSS has lost its lock, it is difficult to reliably detect the position and size of cycle slips. The sampling rate of GNSS receiver is generally 1 Hz, and the data sampling frequency is low. It is difficult to meet the high dynamic application environment. Inertial navigation system is free from external interference, data sampling rate is high, short-term accuracy is high. In this paper, a GPS cycle slip detection and repair algorithm for combined inertial navigation is proposed by introducing the observed values of inertial navigation. The purpose of this paper is to solve the problem of GPS cycle slip detection and repair when a large number of satellites lose lock in complex environment, and to realize GPS high precision real-time dynamic positioning. Focusing on this core goal, this paper, from the point of view of algorithm design and data processing, establishes the mathematical model of MEMS (Microelectromechanical system) inertial navigation space trajectory tracking, and puts forward the GPS observation equation of joint inertial navigation constraint. The epoch difference model of single difference between stars is established to detect and repair the cycle slip. The main contents and achievements of this paper are as follows: (1) the algorithms of attitude updating and tracking of MEMS inertial navigation system are completed. In the aspect of attitude solution, the heading angle, pitch angle and roll angle are calculated by quaternion method. In the aspect of space trajectory tracking, the acceleration transformation from carrier coordinate system to geographical coordinate system is completed, and the track of MEMS space motion is determined by the method of quadratic integration in time domain. According to the theoretical data of simulation plane and slope motion, the deviation of the result is within 10-3m, which shows that the tracking algorithm of MEMS inertial navigation space is accurate and reliable in theory. (2) the processing of the measured data of MEMS inertial navigation is completed. The zero bias calibration of triaxial accelerometer and gyroscope is completed. The median filter is used to reduce the noise of the measured data and the dynamic deviation correction term with time is added. Compared with RTK data, the calculated results of modified MEMS measured data are less than 3 m. (3) A GPS cycle slip detection and repair algorithm based on combined inertial navigation is proposed. Based on the observation model of single difference epoch difference between GPS satellites and the observed data of MEMS inertial navigation system, the mathematical model of GPS cycle slip detection for joint inertial navigation system is established. According to the principle of least square, the integral cycle ambiguity search method of Lambda is used. The cycle slip detection and repair are realized. The experimental results show that under inertial navigation constraints, the cycle slips of a large number of satellites can be successfully detected and the small cycle slips can be detected.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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